assimp/code/AssetLib/M3D/m3d.h

/*
 * m3d.h
 *
 * Copyright (C) 2019 bzt (bztsrc@gitlab)
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * @brief ANSI C89 / C++11 single header importer / exporter SDK for the Model 3D (.M3D) format
 * https://gitlab.com/bztsrc/model3d
 *
 * PNG decompressor included from (with minor modifications to make it C89 valid):
 *  stb_image - v2.13 - public domain image loader - http://nothings.org/stb_image.h
 *
 * @version: 1.0.0
 */

#ifndef _M3D_H_
#define _M3D_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>

/*** configuration ***/
#ifndef M3D_MALLOC
#define M3D_MALLOC(sz) malloc(sz)
#endif
#ifndef M3D_REALLOC
#define M3D_REALLOC(p, nsz) realloc(p, nsz)
#endif
#ifndef M3D_FREE
#define M3D_FREE(p) free(p)
#endif
#ifndef M3D_LOG
#define M3D_LOG(x)
#endif
#ifndef M3D_APIVERSION
#define M3D_APIVERSION 0x0100
#ifndef M3D_DOUBLE
typedef float M3D_FLOAT;
#ifndef M3D_EPSILON
/* carefully choosen for IEEE 754 don't change */
#define M3D_EPSILON ((M3D_FLOAT)1e-7)
#endif
#else
typedef double M3D_FLOAT;
#ifndef M3D_EPSILON
#define M3D_EPSILON ((M3D_FLOAT)1e-14)
#endif
#endif
#if !defined(M3D_SMALLINDEX)
typedef uint32_t M3D_INDEX;
#define M3D_UNDEF 0xffffffff
#define M3D_INDEXMAX 0xfffffffe
#else
typedef uint16_t M3D_INDEX;
#define M3D_UNDEF 0xffff
#define M3D_INDEXMAX 0xfffe
#endif
#define M3D_NOTDEFINED 0xffffffff
#ifndef M3D_NUMBONE
#define M3D_NUMBONE 4
#endif
#ifndef M3D_BONEMAXLEVEL
#define M3D_BONEMAXLEVEL 8
#endif
#ifndef _MSC_VER
#define _inline __inline__
#define _pack __attribute__((packed))
#define _unused __attribute__((unused))
#else
#define _inline
#define _pack
#define _unused __pragma(warning(suppress : 4100))
#endif
#ifndef __cplusplus
#define _register register
#else
#define _register
#endif

#ifdef _WIN32
#    pragma warning(push)
#    pragma warning(disable : 4100 4127 4189 4505 4244 4403  4701 4703)
#    if (_MSC_VER > 1800 )
#        pragma warning(disable : 5573 5744)
#    endif
#endif // _WIN32

/*** File format structures ***/

/**
 * M3D file format structure
 *  3DMO m3dchunk_t file header chunk, may followed by compressed data
 *  HEAD m3dhdr_t model header chunk
 *  n x m3dchunk_t more chunks follow
 *      PRVW preview chunk (optional)
 *      CMAP color map chunk (optional)
 *      TMAP texture map chunk (optional)
 *      VRTS vertex data chunk (optional if it's a material library)
 *      BONE bind-pose skeleton, bone hierarchy chunk (optional)
 *          n x m3db_t contains propably more, but at least one bone
 *          n x m3ds_t skin group records
 *      MTRL* material chunk(s), can be more (optional)
 *          n x m3dp_t each material contains propapbly more, but at least one property
 *                     the properties are configurable with a static array, see m3d_propertytypes
 *      n x m3dchunk_t at least one, but maybe more face chunks
 *          PROC* procedural face, or
 *          MESH* triangle mesh (vertex index list) or
 *          SHPE* mathematical shapes like parameterized surfaces
 *      LBLS* annotation label chunks, can be more (optional)
 *      ACTN* action chunk(s), animation-pose skeletons, can be more (optional)
 *          n x m3dfr_t each action contains probably more, but at least one frame
 *              n x m3dtr_t each frame contains probably more, but at least one transformation
 *      ASET* inlined asset chunk(s), can be more (optional)
 *  OMD3 end chunk
 *
 * Typical chunks for a game engine: 3DMO, HEAD, CMAP, TMAP, VRTS, BONE, MTRL, MESH, ACTN, OMD3
 * Typical chunks for CAD software:  3DMO, HEAD, PRVW, CMAP, TMAP, VRTS, MTRL, SHPE, LBLS, OMD3
 */
#ifdef _MSC_VER
#pragma pack(push)
#pragma pack(1)
#endif

typedef struct {
    char magic[4];
    uint32_t length;
    float scale; /* deliberately not M3D_FLOAT */
    uint32_t types;
} _pack m3dhdr_t;

typedef struct {
    char magic[4];
    uint32_t length;
} _pack m3dchunk_t;

#ifdef _MSC_VER
#pragma pack(pop)
#endif

/*** in-memory model structure ***/

/* textmap entry */
typedef struct {
    M3D_FLOAT u;
    M3D_FLOAT v;
} m3dti_t;
#define m3d_textureindex_t m3dti_t

/* texture */
typedef struct {
    char *name; /* texture name */
    uint8_t *d; /* pixels data */
    uint16_t w; /* width */
    uint16_t h; /* height */
    uint8_t f; /* format, 1 = grayscale, 2 = grayscale+alpha, 3 = rgb, 4 = rgba */
} m3dtx_t;
#define m3d_texturedata_t m3dtx_t

typedef struct {
    M3D_INDEX vertexid;
    M3D_FLOAT weight;
} m3dw_t;
#define m3d_weight_t m3dw_t

/* bone entry */
typedef struct {
    M3D_INDEX parent; /* parent bone index */
    char *name; /* name for this bone */
    M3D_INDEX pos; /* vertex index position */
    M3D_INDEX ori; /* vertex index orientation (quaternion) */
    M3D_INDEX numweight; /* number of controlled vertices */
    m3dw_t *weight; /* weights for those vertices */
    M3D_FLOAT mat4[16]; /* transformation matrix */
} m3db_t;
#define m3d_bone_t m3db_t

/* skin: bone per vertex entry */
typedef struct {
    M3D_INDEX boneid[M3D_NUMBONE];
    M3D_FLOAT weight[M3D_NUMBONE];
} m3ds_t;
#define m3d_skin_t m3ds_t

/* vertex entry */
typedef struct {
    M3D_FLOAT x; /* 3D coordinates and weight */
    M3D_FLOAT y;
    M3D_FLOAT z;
    M3D_FLOAT w;
    uint32_t color; /* default vertex color */
    M3D_INDEX skinid; /* skin index */
#ifdef M3D_VERTEXTYPE
    uint8_t type;
#endif
} m3dv_t;
#define m3d_vertex_t m3dv_t

/* material property formats */
enum {
    m3dpf_color,
    m3dpf_uint8,
    m3dpf_uint16,
    m3dpf_uint32,
    m3dpf_float,
    m3dpf_map
};
typedef struct {
    uint8_t format;
    uint8_t id;
#ifdef M3D_ASCII
#define M3D_PROPERTYDEF(f, i, n) \
    { (f), (i), (char *)(n) }
    char *key;
#else
#define M3D_PROPERTYDEF(f, i, n) \
    { (f), (i) }
#endif
} m3dpd_t;

/* material property types */
/* You shouldn't change the first 8 display and first 4 physical property. Assign the rest as you like. */
enum {
    m3dp_Kd = 0, /* scalar display properties */
    m3dp_Ka,
    m3dp_Ks,
    m3dp_Ns,
    m3dp_Ke,
    m3dp_Tf,
    m3dp_Km,
    m3dp_d,
    m3dp_il,

    m3dp_Pr = 64, /* scalar physical properties */
    m3dp_Pm,
    m3dp_Ps,
    m3dp_Ni,
    m3dp_Nt,

    m3dp_map_Kd = 128, /* textured display map properties */
    m3dp_map_Ka,
    m3dp_map_Ks,
    m3dp_map_Ns,
    m3dp_map_Ke,
    m3dp_map_Tf,
    m3dp_map_Km, /* bump map */
    m3dp_map_D,
    m3dp_map_N, /* normal map */

    m3dp_map_Pr = 192, /* textured physical map properties */
    m3dp_map_Pm,
    m3dp_map_Ps,
    m3dp_map_Ni,
    m3dp_map_Nt
};
enum { /* aliases */
    m3dp_bump = m3dp_map_Km,
    m3dp_map_il = m3dp_map_N,
    m3dp_refl = m3dp_map_Pm
};

/* material property */
typedef struct {
    uint8_t type; /* property type, see "m3dp_*" enumeration */
    union {
        uint32_t color; /* if value is a color, m3dpf_color */
        uint32_t num; /* if value is a number, m3dpf_uint8, m3pf_uint16, m3dpf_uint32 */
        float fnum; /* if value is a floating point number, m3dpf_float */
        M3D_INDEX textureid; /* if value is a texture, m3dpf_map */
    } value;
} m3dp_t;
#define m3d_property_t m3dp_t

/* material entry */
typedef struct {
    char *name; /* name of the material */
    uint8_t numprop; /* number of properties */
    m3dp_t *prop; /* properties array */
} m3dm_t;
#define m3d_material_t m3dm_t

/* face entry */
typedef struct {
    M3D_INDEX materialid; /* material index */
    M3D_INDEX vertex[3]; /* 3D points of the triangle in CCW order */
    M3D_INDEX normal[3]; /* normal vectors */
    M3D_INDEX texcoord[3]; /* UV coordinates */
} m3df_t;
#define m3d_face_t m3df_t

/* shape command types. must match the row in m3d_commandtypes */
enum {
    /* special commands */
    m3dc_use = 0, /* use material */
    m3dc_inc, /* include another shape */
    m3dc_mesh, /* include part of polygon mesh */
    /* approximations */
    m3dc_div, /* subdivision by constant resolution for both u, v */
    m3dc_sub, /* subdivision by constant, different for u and v */
    m3dc_len, /* spacial subdivision by maxlength */
    m3dc_dist, /* subdivision by maxdistance and maxangle */
    /* modifiers */
    m3dc_degu, /* degree for both u, v */
    m3dc_deg, /* separate degree for u and v */
    m3dc_rangeu, /* range for u */
    m3dc_range, /* range for u and v */
    m3dc_paru, /* u parameters (knots) */
    m3dc_parv, /* v parameters */
    m3dc_trim, /* outer trimming curve */
    m3dc_hole, /* inner trimming curve */
    m3dc_scrv, /* spacial curve */
    m3dc_sp, /* special points */
    /* helper curves */
    m3dc_bez1, /* Bezier 1D */
    m3dc_bsp1, /* B-spline 1D */
    m3dc_bez2, /* bezier 2D */
    m3dc_bsp2, /* B-spline 2D */
    /* surfaces */
    m3dc_bezun, /* Bezier 3D with control, UV, normal */
    m3dc_bezu, /* with control and UV */
    m3dc_bezn, /* with control and normal */
    m3dc_bez, /* control points only */
    m3dc_nurbsun, /* B-spline 3D */
    m3dc_nurbsu,
    m3dc_nurbsn,
    m3dc_nurbs,
    m3dc_conn, /* connect surfaces */
    /* geometrical */
    m3dc_line,
    m3dc_polygon,
    m3dc_circle,
    m3dc_cylinder,
    m3dc_shpere,
    m3dc_torus,
    m3dc_cone,
    m3dc_cube
};

/* shape command argument types */
enum {
    m3dcp_mi_t = 1, /* material index */
    m3dcp_hi_t, /* shape index */
    m3dcp_fi_t, /* face index */
    m3dcp_ti_t, /* texture map index */
    m3dcp_vi_t, /* vertex index */
    m3dcp_qi_t, /* vertex index for quaternions */
    m3dcp_vc_t, /* coordinate or radius, float scalar */
    m3dcp_i1_t, /* int8 scalar */
    m3dcp_i2_t, /* int16 scalar */
    m3dcp_i4_t, /* int32 scalar */
    m3dcp_va_t /* variadic arguments */
};

#define M3D_CMDMAXARG 8 /* if you increase this, add more arguments to the macro below */
typedef struct {
#ifdef M3D_ASCII
#define M3D_CMDDEF(t, n, p, a, b, c, d, e, f, g, h)                  \
    {                                                                \
        (char *)(n), (p), { (a), (b), (c), (d), (e), (f), (g), (h) } \
    }
    char *key;
#else
#define M3D_CMDDEF(t, n, p, a, b, c, d, e, f, g, h)     \
    {                                                   \
        (p), { (a), (b), (c), (d), (e), (f), (g), (h) } \
    }
#endif
    uint8_t p;
    uint8_t a[M3D_CMDMAXARG];
} m3dcd_t;

/* shape command */
typedef struct {
    uint16_t type; /* shape type */
    uint32_t *arg; /* arguments array */
} m3dc_t;
#define m3d_shapecommand_t m3dc_t

/* shape entry */
typedef struct {
    char *name; /* name of the mathematical shape */
    M3D_INDEX group; /* group this shape belongs to or -1 */
    uint32_t numcmd; /* number of commands */
    m3dc_t *cmd; /* commands array */
} m3dh_t;
#define m3d_shape_t m3dh_t

/* label entry */
typedef struct {
    char *name; /* name of the annotation layer or NULL */
    char *lang; /* language code or NULL */
    char *text; /* the label text */
    uint32_t color; /* color */
    M3D_INDEX vertexid; /* the vertex the label refers to */
} m3dl_t;
#define m3d_label_t m3dl_t

/* frame transformations / working copy skeleton entry */
typedef struct {
    M3D_INDEX boneid; /* selects a node in bone hierarchy */
    M3D_INDEX pos; /* vertex index new position */
    M3D_INDEX ori; /* vertex index new orientation (quaternion) */
} m3dtr_t;
#define m3d_transform_t m3dtr_t

/* animation frame entry */
typedef struct {
    uint32_t msec; /* frame's position on the timeline, timestamp */
    M3D_INDEX numtransform; /* number of transformations in this frame */
    m3dtr_t *transform; /* transformations */
} m3dfr_t;
#define m3d_frame_t m3dfr_t

/* model action entry */
typedef struct {
    char *name; /* name of the action */
    uint32_t durationmsec; /* duration in millisec (1/1000 sec) */
    M3D_INDEX numframe; /* number of frames in this animation */
    m3dfr_t *frame; /* frames array */
} m3da_t;
#define m3d_action_t m3da_t

/* inlined asset */
typedef struct {
    char *name; /* asset name (same pointer as in texture[].name) */
    uint8_t *data; /* compressed asset data */
    uint32_t length; /* compressed data length */
} m3di_t;
#define m3d_inlinedasset_t m3di_t

/*** in-memory model structure ***/
#define M3D_FLG_FREERAW (1 << 0)
#define M3D_FLG_FREESTR (1 << 1)
#define M3D_FLG_MTLLIB (1 << 2)
#define M3D_FLG_GENNORM (1 << 3)

typedef struct {
    m3dhdr_t *raw; /* pointer to raw data */
    char flags; /* internal flags */
    signed char errcode; /* returned error code */
    char vc_s, vi_s, si_s, ci_s, ti_s, bi_s, nb_s, sk_s, fc_s, hi_s, fi_s; /* decoded sizes for types */
    char *name; /* name of the model, like "Utah teapot" */
    char *license; /* usage condition or license, like "MIT", "LGPL" or "BSD-3clause" */
    char *author; /* nickname, email, homepage or github URL etc. */
    char *desc; /* comments, descriptions. May contain '\n' newline character */
    M3D_FLOAT scale; /* the model's bounding cube's size in SI meters */
    M3D_INDEX numcmap;
    uint32_t *cmap; /* color map */
    M3D_INDEX numtmap;
    m3dti_t *tmap; /* texture map indices */
    M3D_INDEX numtexture;
    m3dtx_t *texture; /* uncompressed textures */
    M3D_INDEX numbone;
    m3db_t *bone; /* bone hierarchy */
    M3D_INDEX numvertex;
    m3dv_t *vertex; /* vertex data */
    M3D_INDEX numskin;
    m3ds_t *skin; /* skin data */
    M3D_INDEX nummaterial;
    m3dm_t *material; /* material list */
    M3D_INDEX numface;
    m3df_t *face; /* model face, polygon (triangle) mesh */
    M3D_INDEX numshape;
    m3dh_t *shape; /* model face, shape commands */
    M3D_INDEX numlabel;
    m3dl_t *label; /* annotation labels */
    M3D_INDEX numaction;
    m3da_t *action; /* action animations */
    M3D_INDEX numinlined;
    m3di_t *inlined; /* inlined assets */
    M3D_INDEX numextra;
    m3dchunk_t **extra; /* unknown chunks, application / engine specific data probably */
    m3di_t preview; /* preview chunk */
} m3d_t;

/*** export parameters ***/
#define M3D_EXP_INT8 0
#define M3D_EXP_INT16 1
#define M3D_EXP_FLOAT 2
#define M3D_EXP_DOUBLE 3

#define M3D_EXP_NOCMAP (1 << 0)
#define M3D_EXP_NOMATERIAL (1 << 1)
#define M3D_EXP_NOFACE (1 << 2)
#define M3D_EXP_NONORMAL (1 << 3)
#define M3D_EXP_NOTXTCRD (1 << 4)
#define M3D_EXP_FLIPTXTCRD (1 << 5)
#define M3D_EXP_NORECALC (1 << 6)
#define M3D_EXP_IDOSUCK (1 << 7)
#define M3D_EXP_NOBONE (1 << 8)
#define M3D_EXP_NOACTION (1 << 9)
#define M3D_EXP_INLINE (1 << 10)
#define M3D_EXP_EXTRA (1 << 11)
#define M3D_EXP_NOZLIB (1 << 14)
#define M3D_EXP_ASCII (1 << 15)

/*** error codes ***/
#define M3D_SUCCESS 0
#define M3D_ERR_ALLOC -1
#define M3D_ERR_BADFILE -2
#define M3D_ERR_UNIMPL -65
#define M3D_ERR_UNKPROP -66
#define M3D_ERR_UNKMESH -67
#define M3D_ERR_UNKIMG -68
#define M3D_ERR_UNKFRAME -69
#define M3D_ERR_UNKCMD -70
#define M3D_ERR_TRUNC -71
#define M3D_ERR_CMAP -72
#define M3D_ERR_TMAP -73
#define M3D_ERR_VRTS -74
#define M3D_ERR_BONE -75
#define M3D_ERR_MTRL -76
#define M3D_ERR_SHPE -77

#define M3D_ERR_ISFATAL(x) ((x) < 0 && (x) > -65)

/* callbacks */
typedef unsigned char *(*m3dread_t)(char *filename, unsigned int *size); /* read file contents into buffer */
typedef void (*m3dfree_t)(void *buffer); /* free file contents buffer */
typedef int (*m3dtxsc_t)(const char *name, const void *script, uint32_t len, m3dtx_t *output); /* interpret texture script */
typedef int (*m3dprsc_t)(const char *name, const void *script, uint32_t len, m3d_t *model); /* interpret surface script */
#endif /* ifndef M3D_APIVERSION */

/*** C prototypes ***/
/* import / export */
m3d_t *m3d_load(unsigned char *data, m3dread_t readfilecb, m3dfree_t freecb, m3d_t *mtllib);
unsigned char *m3d_save(m3d_t *model, int quality, int flags, unsigned int *size);
void m3d_free(m3d_t *model);
/* generate animation pose skeleton */
m3dtr_t *m3d_frame(m3d_t *model, M3D_INDEX actionid, M3D_INDEX frameid, m3dtr_t *skeleton);
m3db_t *m3d_pose(m3d_t *model, M3D_INDEX actionid, uint32_t msec);

/* private prototypes used by both importer and exporter */
char *_m3d_safestr(char *in, int morelines);

/*** C implementation ***/
#ifdef M3D_IMPLEMENTATION
#if !defined(M3D_NOIMPORTER) || defined(M3D_EXPORTER)
/* material property definitions */
static m3dpd_t m3d_propertytypes[] = {
    M3D_PROPERTYDEF(m3dpf_color, m3dp_Kd, "Kd"), /* diffuse color */
    M3D_PROPERTYDEF(m3dpf_color, m3dp_Ka, "Ka"), /* ambient color */
    M3D_PROPERTYDEF(m3dpf_color, m3dp_Ks, "Ks"), /* specular color */
    M3D_PROPERTYDEF(m3dpf_float, m3dp_Ns, "Ns"), /* specular exponent */
    M3D_PROPERTYDEF(m3dpf_color, m3dp_Ke, "Ke"), /* emissive (emitting light of this color) */
    M3D_PROPERTYDEF(m3dpf_color, m3dp_Tf, "Tf"), /* transmission color */
    M3D_PROPERTYDEF(m3dpf_float, m3dp_Km, "Km"), /* bump strength */
    M3D_PROPERTYDEF(m3dpf_float, m3dp_d, "d"), /* dissolve (transparency) */
    M3D_PROPERTYDEF(m3dpf_uint8, m3dp_il, "il"), /* illumination model (informational, ignored by PBR-shaders) */

    M3D_PROPERTYDEF(m3dpf_float, m3dp_Pr, "Pr"), /* roughness */
    M3D_PROPERTYDEF(m3dpf_float, m3dp_Pm, "Pm"), /* metallic, also reflection */
    M3D_PROPERTYDEF(m3dpf_float, m3dp_Ps, "Ps"), /* sheen */
    M3D_PROPERTYDEF(m3dpf_float, m3dp_Ni, "Ni"), /* index of refraction (optical density) */
    M3D_PROPERTYDEF(m3dpf_float, m3dp_Nt, "Nt"), /* thickness of face in millimeter, for printing */

    /* aliases, note that "map_*" aliases are handled automatically */
    M3D_PROPERTYDEF(m3dpf_map, m3dp_map_Km, "bump"),
    M3D_PROPERTYDEF(m3dpf_map, m3dp_map_N, "map_N"), /* as normal map has no scalar version, it's counterpart is 'il' */
    M3D_PROPERTYDEF(m3dpf_map, m3dp_map_Pm, "refl")
};
/* shape command definitions. if more commands start with the same string, the longer must come first */
static m3dcd_t m3d_commandtypes[] = {
    /* technical */
    M3D_CMDDEF(m3dc_use, "use", 1, m3dcp_mi_t, 0, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_inc, "inc", 3, m3dcp_hi_t, m3dcp_vi_t, m3dcp_qi_t, m3dcp_vi_t, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_mesh, "mesh", 1, m3dcp_fi_t, m3dcp_fi_t, m3dcp_vi_t, m3dcp_qi_t, m3dcp_vi_t, 0, 0, 0),
    /* approximations */
    M3D_CMDDEF(m3dc_div, "div", 1, m3dcp_vc_t, 0, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_sub, "sub", 2, m3dcp_vc_t, m3dcp_vc_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_len, "len", 1, m3dcp_vc_t, 0, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_dist, "dist", 2, m3dcp_vc_t, m3dcp_vc_t, 0, 0, 0, 0, 0, 0),
    /* modifiers */
    M3D_CMDDEF(m3dc_degu, "degu", 1, m3dcp_i1_t, 0, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_deg, "deg", 2, m3dcp_i1_t, m3dcp_i1_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_rangeu, "rangeu", 1, m3dcp_ti_t, 0, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_range, "range", 2, m3dcp_ti_t, m3dcp_ti_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_paru, "paru", 2, m3dcp_va_t, m3dcp_vc_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_parv, "parv", 2, m3dcp_va_t, m3dcp_vc_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_trim, "trim", 3, m3dcp_va_t, m3dcp_ti_t, m3dcp_i2_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_hole, "hole", 3, m3dcp_va_t, m3dcp_ti_t, m3dcp_i2_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_scrv, "scrv", 3, m3dcp_va_t, m3dcp_ti_t, m3dcp_i2_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_sp, "sp", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    /* helper curves */
    M3D_CMDDEF(m3dc_bez1, "bez1", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_bsp1, "bsp1", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_bez2, "bez2", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_bsp2, "bsp2", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    /* surfaces */
    M3D_CMDDEF(m3dc_bezun, "bezun", 4, m3dcp_va_t, m3dcp_vi_t, m3dcp_ti_t, m3dcp_vi_t, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_bezu, "bezu", 3, m3dcp_va_t, m3dcp_vi_t, m3dcp_ti_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_bezn, "bezn", 3, m3dcp_va_t, m3dcp_vi_t, m3dcp_vi_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_bez, "bez", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_nurbsun, "nurbsun", 4, m3dcp_va_t, m3dcp_vi_t, m3dcp_ti_t, m3dcp_vi_t, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_nurbsu, "nurbsu", 3, m3dcp_va_t, m3dcp_vi_t, m3dcp_ti_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_nurbsn, "nurbsn", 3, m3dcp_va_t, m3dcp_vi_t, m3dcp_vi_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_nurbs, "nurbs", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_conn, "conn", 6, m3dcp_i2_t, m3dcp_ti_t, m3dcp_i2_t, m3dcp_i2_t, m3dcp_ti_t, m3dcp_i2_t, 0, 0),
    /* geometrical */
    M3D_CMDDEF(m3dc_line, "line", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_polygon, "polygon", 2, m3dcp_va_t, m3dcp_vi_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_circle, "circle", 3, m3dcp_vi_t, m3dcp_qi_t, m3dcp_vc_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_cylinder, "cylinder", 6, m3dcp_vi_t, m3dcp_qi_t, m3dcp_vc_t, m3dcp_vi_t, m3dcp_qi_t, m3dcp_vc_t, 0, 0),
    M3D_CMDDEF(m3dc_shpere, "shpere", 2, m3dcp_vi_t, m3dcp_vc_t, 0, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_torus, "torus", 4, m3dcp_vi_t, m3dcp_qi_t, m3dcp_vc_t, m3dcp_vc_t, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_cone, "cone", 3, m3dcp_vi_t, m3dcp_vi_t, m3dcp_vi_t, 0, 0, 0, 0, 0),
    M3D_CMDDEF(m3dc_cube, "cube", 3, m3dcp_vi_t, m3dcp_vi_t, m3dcp_vi_t, 0, 0, 0, 0, 0)
};
#endif

#include <stdlib.h>
#include <string.h>

#if !defined(M3D_NOIMPORTER) && !defined(STBI_INCLUDE_STB_IMAGE_H)
/* PNG decompressor from

   stb_image - v2.23 - public domain image loader - http://nothings.org/stb_image.h
*/
static const char *_m3dstbi__g_failure_reason;

enum {
    STBI_default = 0,

    STBI_grey = 1,
    STBI_grey_alpha = 2,
    STBI_rgb = 3,
    STBI_rgb_alpha = 4
};

enum {
    STBI__SCAN_load = 0,
    STBI__SCAN_type,
    STBI__SCAN_header
};

typedef unsigned short _m3dstbi_us;

typedef uint16_t _m3dstbi__uint16;
typedef int16_t _m3dstbi__int16;
typedef uint32_t _m3dstbi__uint32;
typedef int32_t _m3dstbi__int32;

typedef struct
{
    _m3dstbi__uint32 img_x, img_y;
    int img_n, img_out_n;

    void *io_user_data;

    int read_from_callbacks;
    int buflen;
    unsigned char buffer_start[128];

    unsigned char *img_buffer, *img_buffer_end;
    unsigned char *img_buffer_original, *img_buffer_original_end;
} _m3dstbi__context;

typedef struct
{
    int bits_per_channel;
    int num_channels;
    int channel_order;
} _m3dstbi__result_info;

#define STBI_ASSERT(v)
#define STBI_NOTUSED(v) (void)sizeof(v)
#define STBI__BYTECAST(x) ((unsigned char)((x)&255))
#define STBI_MALLOC(sz) M3D_MALLOC(sz)
#define STBI_REALLOC(p, newsz) M3D_REALLOC(p, newsz)
#define STBI_FREE(p) M3D_FREE(p)
#define STBI_REALLOC_SIZED(p, oldsz, newsz) STBI_REALLOC(p, newsz)

_inline static unsigned char _m3dstbi__get8(_m3dstbi__context *s) {
    if (s->img_buffer < s->img_buffer_end)
        return *s->img_buffer++;
    return 0;
}

_inline static int _m3dstbi__at_eof(_m3dstbi__context *s) {
    return s->img_buffer >= s->img_buffer_end;
}

static void _m3dstbi__skip(_m3dstbi__context *s, int n) {
    if (n < 0) {
        s->img_buffer = s->img_buffer_end;
        return;
    }
    s->img_buffer += n;
}

static int _m3dstbi__getn(_m3dstbi__context *s, unsigned char *buffer, int n) {
    if (s->img_buffer + n <= s->img_buffer_end) {
        memcpy(buffer, s->img_buffer, n);
        s->img_buffer += n;
        return 1;
    } else
        return 0;
}

static int _m3dstbi__get16be(_m3dstbi__context *s) {
    int z = _m3dstbi__get8(s);
    return (z << 8) + _m3dstbi__get8(s);
}

static _m3dstbi__uint32 _m3dstbi__get32be(_m3dstbi__context *s) {
    _m3dstbi__uint32 z = _m3dstbi__get16be(s);
    return (z << 16) + _m3dstbi__get16be(s);
}

#define _m3dstbi__err(x, y) _m3dstbi__errstr(y)
static int _m3dstbi__errstr(const char *str) {
    _m3dstbi__g_failure_reason = str;
    return 0;
}

_inline static void *_m3dstbi__malloc(size_t size) {
    return STBI_MALLOC(size);
}

static int _m3dstbi__addsizes_valid(int a, int b) {
    if (b < 0) return 0;
    return a <= 2147483647 - b;
}

static int _m3dstbi__mul2sizes_valid(int a, int b) {
    if (a < 0 || b < 0) return 0;
    if (b == 0) return 1;
    return a <= 2147483647 / b;
}

static int _m3dstbi__mad2sizes_valid(int a, int b, int add) {
    return _m3dstbi__mul2sizes_valid(a, b) && _m3dstbi__addsizes_valid(a * b, add);
}

static int _m3dstbi__mad3sizes_valid(int a, int b, int c, int add) {
    return _m3dstbi__mul2sizes_valid(a, b) && _m3dstbi__mul2sizes_valid(a * b, c) &&
           _m3dstbi__addsizes_valid(a * b * c, add);
}

static void *_m3dstbi__malloc_mad2(int a, int b, int add) {
    if (!_m3dstbi__mad2sizes_valid(a, b, add)) return NULL;
    return _m3dstbi__malloc(a * b + add);
}

static void *_m3dstbi__malloc_mad3(int a, int b, int c, int add) {
    if (!_m3dstbi__mad3sizes_valid(a, b, c, add)) return NULL;
    return _m3dstbi__malloc(a * b * c + add);
}

static unsigned char _m3dstbi__compute_y(int r, int g, int b) {
    return (unsigned char)(((r * 77) + (g * 150) + (29 * b)) >> 8);
}

static unsigned char *_m3dstbi__convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y) {
    int i, j;
    unsigned char *good;

    if (req_comp == img_n) return data;
    STBI_ASSERT(req_comp >= 1 && req_comp <= 4);

    good = (unsigned char *)_m3dstbi__malloc_mad3(req_comp, x, y, 0);
    if (good == NULL) {
        STBI_FREE(data);
        _m3dstbi__err("outofmem", "Out of memory");
        return NULL;
    }

    for (j = 0; j < (int)y; ++j) {
        unsigned char *src = data + j * x * img_n;
        unsigned char *dest = good + j * x * req_comp;

#define STBI__COMBO(a, b) ((a)*8 + (b))
#define STBI__CASE(a, b)    \
    case STBI__COMBO(a, b): \
        for (i = x - 1; i >= 0; --i, src += a, dest += b)
        switch (STBI__COMBO(img_n, req_comp)) {
            STBI__CASE(1, 2) { dest[0] = src[0], dest[1] = 255; }
            break;
            STBI__CASE(1, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
            break;
            STBI__CASE(1, 4) { dest[0] = dest[1] = dest[2] = src[0], dest[3] = 255; }
            break;
            STBI__CASE(2, 1) { dest[0] = src[0]; }
            break;
            STBI__CASE(2, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
            break;
            STBI__CASE(2, 4) { dest[0] = dest[1] = dest[2] = src[0], dest[3] = src[1]; }
            break;
            STBI__CASE(3, 4) { dest[0] = src[0], dest[1] = src[1], dest[2] = src[2], dest[3] = 255; }
            break;
            STBI__CASE(3, 1) { dest[0] = _m3dstbi__compute_y(src[0], src[1], src[2]); }
            break;
            STBI__CASE(3, 2) { dest[0] = _m3dstbi__compute_y(src[0], src[1], src[2]), dest[1] = 255; }
            break;
            STBI__CASE(4, 1) { dest[0] = _m3dstbi__compute_y(src[0], src[1], src[2]); }
            break;
            STBI__CASE(4, 2) { dest[0] = _m3dstbi__compute_y(src[0], src[1], src[2]), dest[1] = src[3]; }
            break;
            STBI__CASE(4, 3) { dest[0] = src[0], dest[1] = src[1], dest[2] = src[2]; }
            break;
            default: STBI_ASSERT(0);
        }
#undef STBI__CASE
    }

    STBI_FREE(data);
    return good;
}

static _m3dstbi__uint16 _m3dstbi__compute_y_16(int r, int g, int b) {
    return (_m3dstbi__uint16)(((r * 77) + (g * 150) + (29 * b)) >> 8);
}

static _m3dstbi__uint16 *_m3dstbi__convert_format16(_m3dstbi__uint16 *data, int img_n, int req_comp, unsigned int x, unsigned int y) {
    int i, j;
    _m3dstbi__uint16 *good;

    if (req_comp == img_n) return data;
    STBI_ASSERT(req_comp >= 1 && req_comp <= 4);

    good = (_m3dstbi__uint16 *)_m3dstbi__malloc(req_comp * x * y * 2);
    if (good == NULL) {
        STBI_FREE(data);
        _m3dstbi__err("outofmem", "Out of memory");
        return NULL;
    }

    for (j = 0; j < (int)y; ++j) {
        _m3dstbi__uint16 *src = data + j * x * img_n;
        _m3dstbi__uint16 *dest = good + j * x * req_comp;

#define STBI__COMBO(a, b) ((a)*8 + (b))
#define STBI__CASE(a, b)    \
    case STBI__COMBO(a, b): \
        for (i = x - 1; i >= 0; --i, src += a, dest += b)
        switch (STBI__COMBO(img_n, req_comp)) {
            STBI__CASE(1, 2) { dest[0] = src[0], dest[1] = 0xffff; }
            break;
            STBI__CASE(1, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
            break;
            STBI__CASE(1, 4) { dest[0] = dest[1] = dest[2] = src[0], dest[3] = 0xffff; }
            break;
            STBI__CASE(2, 1) { dest[0] = src[0]; }
            break;
            STBI__CASE(2, 3) { dest[0] = dest[1] = dest[2] = src[0]; }
            break;
            STBI__CASE(2, 4) { dest[0] = dest[1] = dest[2] = src[0], dest[3] = src[1]; }
            break;
            STBI__CASE(3, 4) { dest[0] = src[0], dest[1] = src[1], dest[2] = src[2], dest[3] = 0xffff; }
            break;
            STBI__CASE(3, 1) { dest[0] = _m3dstbi__compute_y_16(src[0], src[1], src[2]); }
            break;
            STBI__CASE(3, 2) { dest[0] = _m3dstbi__compute_y_16(src[0], src[1], src[2]), dest[1] = 0xffff; }
            break;
            STBI__CASE(4, 1) { dest[0] = _m3dstbi__compute_y_16(src[0], src[1], src[2]); }
            break;
            STBI__CASE(4, 2) { dest[0] = _m3dstbi__compute_y_16(src[0], src[1], src[2]), dest[1] = src[3]; }
            break;
            STBI__CASE(4, 3) { dest[0] = src[0], dest[1] = src[1], dest[2] = src[2]; }
            break;
            default: STBI_ASSERT(0);
        }
#undef STBI__CASE
    }

    STBI_FREE(data);
    return good;
}

#define STBI__ZFAST_BITS 9
#define STBI__ZFAST_MASK ((1 << STBI__ZFAST_BITS) - 1)

typedef struct
{
    _m3dstbi__uint16 fast[1 << STBI__ZFAST_BITS];
    _m3dstbi__uint16 firstcode[16];
    int maxcode[17];
    _m3dstbi__uint16 firstsymbol[16];
    unsigned char size[288];
    _m3dstbi__uint16 value[288];
} _m3dstbi__zhuffman;

_inline static int _m3dstbi__bitreverse16(int n) {
    n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1);
    n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2);
    n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4);
    n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8);
    return n;
}

_inline static int _m3dstbi__bit_reverse(int v, int bits) {
    STBI_ASSERT(bits <= 16);
    return _m3dstbi__bitreverse16(v) >> (16 - bits);
}

static int _m3dstbi__zbuild_huffman(_m3dstbi__zhuffman *z, unsigned char *sizelist, int num) {
    int i, k = 0;
    int code, next_code[16], sizes[17];

    memset(sizes, 0, sizeof(sizes));
    memset(z->fast, 0, sizeof(z->fast));
    for (i = 0; i < num; ++i)
        ++sizes[sizelist[i]];
    sizes[0] = 0;
    for (i = 1; i < 16; ++i)
        if (sizes[i] > (1 << i))
            return _m3dstbi__err("bad sizes", "Corrupt PNG");
    code = 0;
    for (i = 1; i < 16; ++i) {
        next_code[i] = code;
        z->firstcode[i] = (_m3dstbi__uint16)code;
        z->firstsymbol[i] = (_m3dstbi__uint16)k;
        code = (code + sizes[i]);
        if (sizes[i])
            if (code - 1 >= (1 << i)) return _m3dstbi__err("bad codelengths", "Corrupt PNG");
        z->maxcode[i] = code << (16 - i);
        code <<= 1;
        k += sizes[i];
    }
    z->maxcode[16] = 0x10000;
    for (i = 0; i < num; ++i) {
        int s = sizelist[i];
        if (s) {
            int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s];
            _m3dstbi__uint16 fastv = (_m3dstbi__uint16)((s << 9) | i);
            z->size[c] = (unsigned char)s;
            z->value[c] = (_m3dstbi__uint16)i;
            if (s <= STBI__ZFAST_BITS) {
                int j = _m3dstbi__bit_reverse(next_code[s], s);
                while (j < (1 << STBI__ZFAST_BITS)) {
                    z->fast[j] = fastv;
                    j += (1 << s);
                }
            }
            ++next_code[s];
        }
    }
    return 1;
}

typedef struct
{
    unsigned char *zbuffer, *zbuffer_end;
    int num_bits;
    _m3dstbi__uint32 code_buffer;

    char *zout;
    char *zout_start;
    char *zout_end;
    int z_expandable;

    _m3dstbi__zhuffman z_length, z_distance;
} _m3dstbi__zbuf;

_inline static unsigned char _m3dstbi__zget8(_m3dstbi__zbuf *z) {
    if (z->zbuffer >= z->zbuffer_end) return 0;
    return *z->zbuffer++;
}

static void _m3dstbi__fill_bits(_m3dstbi__zbuf *z) {
    do {
        STBI_ASSERT(z->code_buffer < (1U << z->num_bits));
        z->code_buffer |= (unsigned int)_m3dstbi__zget8(z) << z->num_bits;
        z->num_bits += 8;
    } while (z->num_bits <= 24);
}

_inline static unsigned int _m3dstbi__zreceive(_m3dstbi__zbuf *z, int n) {
    unsigned int k;
    if (z->num_bits < n) _m3dstbi__fill_bits(z);
    k = z->code_buffer & ((1 << n) - 1);
    z->code_buffer >>= n;
    z->num_bits -= n;
    return k;
}

static int _m3dstbi__zhuffman_decode_slowpath(_m3dstbi__zbuf *a, _m3dstbi__zhuffman *z) {
    int b, s, k;
    k = _m3dstbi__bit_reverse(a->code_buffer, 16);
    for (s = STBI__ZFAST_BITS + 1;; ++s)
        if (k < z->maxcode[s])
            break;
    if (s == 16) return -1;
    b = (k >> (16 - s)) - z->firstcode[s] + z->firstsymbol[s];
    STBI_ASSERT(z->size[b] == s);
    a->code_buffer >>= s;
    a->num_bits -= s;
    return z->value[b];
}

_inline static int _m3dstbi__zhuffman_decode(_m3dstbi__zbuf *a, _m3dstbi__zhuffman *z) {
    int b, s;
    if (a->num_bits < 16) _m3dstbi__fill_bits(a);
    b = z->fast[a->code_buffer & STBI__ZFAST_MASK];
    if (b) {
        s = b >> 9;
        a->code_buffer >>= s;
        a->num_bits -= s;
        return b & 511;
    }
    return _m3dstbi__zhuffman_decode_slowpath(a, z);
}

static int _m3dstbi__zexpand(_m3dstbi__zbuf *z, char *zout, int n) {
    char *q;
    int cur, limit, old_limit;
    z->zout = zout;
    if (!z->z_expandable) return _m3dstbi__err("output buffer limit", "Corrupt PNG");
    cur = (int)(z->zout - z->zout_start);
    limit = old_limit = (int)(z->zout_end - z->zout_start);
    while (cur + n > limit)
        limit *= 2;
    q = (char *)STBI_REALLOC_SIZED(z->zout_start, old_limit, limit);
    STBI_NOTUSED(old_limit);
    if (q == NULL) return _m3dstbi__err("outofmem", "Out of memory");
    z->zout_start = q;
    z->zout = q + cur;
    z->zout_end = q + limit;
    return 1;
}

static int _m3dstbi__zlength_base[31] = {
    3, 4, 5, 6, 7, 8, 9, 10, 11, 13,
    15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
    67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
};

static int _m3dstbi__zlength_extra[31] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 0, 0 };

static int _m3dstbi__zdist_base[32] = { 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
    257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 0, 0 };

static int _m3dstbi__zdist_extra[32] = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13 };

static int _m3dstbi__parse_huffman_block(_m3dstbi__zbuf *a) {
    char *zout = a->zout;
    for (;;) {
        int z = _m3dstbi__zhuffman_decode(a, &a->z_length);
        if (z < 256) {
            if (z < 0) return _m3dstbi__err("bad huffman code", "Corrupt PNG");
            if (zout >= a->zout_end) {
                if (!_m3dstbi__zexpand(a, zout, 1)) return 0;
                zout = a->zout;
            }
            *zout++ = (char)z;
        } else {
            unsigned char *p;
            int len, dist;
            if (z == 256) {
                a->zout = zout;
                return 1;
            }
            z -= 257;
            len = _m3dstbi__zlength_base[z];
            if (_m3dstbi__zlength_extra[z]) len += _m3dstbi__zreceive(a, _m3dstbi__zlength_extra[z]);
            z = _m3dstbi__zhuffman_decode(a, &a->z_distance);
            if (z < 0) return _m3dstbi__err("bad huffman code", "Corrupt PNG");
            dist = _m3dstbi__zdist_base[z];
            if (_m3dstbi__zdist_extra[z]) dist += _m3dstbi__zreceive(a, _m3dstbi__zdist_extra[z]);
            if (zout - a->zout_start < dist) return _m3dstbi__err("bad dist", "Corrupt PNG");
            if (zout + len > a->zout_end) {
                if (!_m3dstbi__zexpand(a, zout, len)) return 0;
                zout = a->zout;
            }
            p = (unsigned char *)(zout - dist);
            if (dist == 1) {
                unsigned char v = *p;
                if (len) {
                    do
                        *zout++ = v;
                    while (--len);
                }
            } else {
                if (len) {
                    do
                        *zout++ = *p++;
                    while (--len);
                }
            }
        }
    }
}

static int _m3dstbi__compute_huffman_codes(_m3dstbi__zbuf *a) {
    static unsigned char length_dezigzag[19] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
    _m3dstbi__zhuffman z_codelength;
    unsigned char lencodes[286 + 32 + 137];
    unsigned char codelength_sizes[19];
    int i, n;

    int hlit = _m3dstbi__zreceive(a, 5) + 257;
    int hdist = _m3dstbi__zreceive(a, 5) + 1;
    int hclen = _m3dstbi__zreceive(a, 4) + 4;
    int ntot = hlit + hdist;

    memset(codelength_sizes, 0, sizeof(codelength_sizes));
    for (i = 0; i < hclen; ++i) {
        int s = _m3dstbi__zreceive(a, 3);
        codelength_sizes[length_dezigzag[i]] = (unsigned char)s;
    }
    if (!_m3dstbi__zbuild_huffman(&z_codelength, codelength_sizes, 19)) return 0;

    n = 0;
    while (n < ntot) {
        int c = _m3dstbi__zhuffman_decode(a, &z_codelength);
        if (c < 0 || c >= 19) return _m3dstbi__err("bad codelengths", "Corrupt PNG");
        if (c < 16)
            lencodes[n++] = (unsigned char)c;
        else {
            unsigned char fill = 0;
            if (c == 16) {
                c = _m3dstbi__zreceive(a, 2) + 3;
                if (n == 0) return _m3dstbi__err("bad codelengths", "Corrupt PNG");
                fill = lencodes[n - 1];
            } else if (c == 17)
                c = _m3dstbi__zreceive(a, 3) + 3;
            else {
                STBI_ASSERT(c == 18);
                c = _m3dstbi__zreceive(a, 7) + 11;
            }
            if (ntot - n < c) return _m3dstbi__err("bad codelengths", "Corrupt PNG");
            memset(lencodes + n, fill, c);
            n += c;
        }
    }
    if (n != ntot) return _m3dstbi__err("bad codelengths", "Corrupt PNG");
    if (!_m3dstbi__zbuild_huffman(&a->z_length, lencodes, hlit)) return 0;
    if (!_m3dstbi__zbuild_huffman(&a->z_distance, lencodes + hlit, hdist)) return 0;
    return 1;
}

_inline static int _m3dstbi__parse_uncompressed_block(_m3dstbi__zbuf *a) {
    unsigned char header[4];
    int len, nlen, k;
    if (a->num_bits & 7)
        _m3dstbi__zreceive(a, a->num_bits & 7);
    k = 0;
    while (a->num_bits > 0) {
        header[k++] = (unsigned char)(a->code_buffer & 255);
        a->code_buffer >>= 8;
        a->num_bits -= 8;
    }
    STBI_ASSERT(a->num_bits == 0);
    while (k < 4)
        header[k++] = _m3dstbi__zget8(a);
    len = header[1] * 256 + header[0];
    nlen = header[3] * 256 + header[2];
    if (nlen != (len ^ 0xffff)) return _m3dstbi__err("zlib corrupt", "Corrupt PNG");
    if (a->zbuffer + len > a->zbuffer_end) return _m3dstbi__err("read past buffer", "Corrupt PNG");
    if (a->zout + len > a->zout_end)
        if (!_m3dstbi__zexpand(a, a->zout, len)) return 0;
    memcpy(a->zout, a->zbuffer, len);
    a->zbuffer += len;
    a->zout += len;
    return 1;
}

static int _m3dstbi__parse_zlib_header(_m3dstbi__zbuf *a) {
    int cmf = _m3dstbi__zget8(a);
    int cm = cmf & 15;
    /* int cinfo = cmf >> 4; */
    int flg = _m3dstbi__zget8(a);
    if ((cmf * 256 + flg) % 31 != 0) return _m3dstbi__err("bad zlib header", "Corrupt PNG");
    if (flg & 32) return _m3dstbi__err("no preset dict", "Corrupt PNG");
    if (cm != 8) return _m3dstbi__err("bad compression", "Corrupt PNG");
    return 1;
}

static unsigned char _m3dstbi__zdefault_length[288], _m3dstbi__zdefault_distance[32];
static void _m3dstbi__init_zdefaults(void) {
    int i;
    for (i = 0; i <= 143; ++i)
        _m3dstbi__zdefault_length[i] = 8;
    for (; i <= 255; ++i)
        _m3dstbi__zdefault_length[i] = 9;
    for (; i <= 279; ++i)
        _m3dstbi__zdefault_length[i] = 7;
    for (; i <= 287; ++i)
        _m3dstbi__zdefault_length[i] = 8;

    for (i = 0; i <= 31; ++i)
        _m3dstbi__zdefault_distance[i] = 5;
}

static int _m3dstbi__parse_zlib(_m3dstbi__zbuf *a, int parse_header) {
    int final, type;
    if (parse_header)
        if (!_m3dstbi__parse_zlib_header(a)) return 0;
    a->num_bits = 0;
    a->code_buffer = 0;
    do {
        final = _m3dstbi__zreceive(a, 1);
        type = _m3dstbi__zreceive(a, 2);
        if (type == 0) {
            if (!_m3dstbi__parse_uncompressed_block(a)) return 0;
        } else if (type == 3) {
            return 0;
        } else {
            if (type == 1) {
                if (!_m3dstbi__zbuild_huffman(&a->z_length, _m3dstbi__zdefault_length, 288)) return 0;
                if (!_m3dstbi__zbuild_huffman(&a->z_distance, _m3dstbi__zdefault_distance, 32)) return 0;
            } else {
                if (!_m3dstbi__compute_huffman_codes(a)) return 0;
            }
            if (!_m3dstbi__parse_huffman_block(a)) return 0;
        }
    } while (!final);
    return 1;
}

static int _m3dstbi__do_zlib(_m3dstbi__zbuf *a, char *obuf, int olen, int exp, int parse_header) {
    a->zout_start = obuf;
    a->zout = obuf;
    a->zout_end = obuf + olen;
    a->z_expandable = exp;
    _m3dstbi__init_zdefaults();
    return _m3dstbi__parse_zlib(a, parse_header);
}

char *_m3dstbi_zlib_decode_malloc_guesssize_headerflag(const char *buffer, int len, int initial_size, int *outlen, int parse_header) {
    _m3dstbi__zbuf a;
    char *p = (char *)_m3dstbi__malloc(initial_size);
    if (p == NULL) return NULL;
    a.zbuffer = (unsigned char *)buffer;
    a.zbuffer_end = (unsigned char *)buffer + len;
    if (_m3dstbi__do_zlib(&a, p, initial_size, 1, parse_header)) {
        if (outlen) *outlen = (int)(a.zout - a.zout_start);
        return a.zout_start;
    } else {
        STBI_FREE(a.zout_start);
        return NULL;
    }
}

typedef struct
{
    _m3dstbi__uint32 length;
    _m3dstbi__uint32 type;
} _m3dstbi__pngchunk;

static _m3dstbi__pngchunk _m3dstbi__get_chunk_header(_m3dstbi__context *s) {
    _m3dstbi__pngchunk c;
    c.length = _m3dstbi__get32be(s);
    c.type = _m3dstbi__get32be(s);
    return c;
}

_inline static int _m3dstbi__check_png_header(_m3dstbi__context *s) {
    static unsigned char png_sig[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
    int i;
    for (i = 0; i < 8; ++i)
        if (_m3dstbi__get8(s) != png_sig[i]) return _m3dstbi__err("bad png sig", "Not a PNG");
    return 1;
}

typedef struct
{
    _m3dstbi__context *s;
    unsigned char *idata, *expanded, *out;
    int depth;
} _m3dstbi__png;

enum {
    STBI__F_none = 0,
    STBI__F_sub = 1,
    STBI__F_up = 2,
    STBI__F_avg = 3,
    STBI__F_paeth = 4,
    STBI__F_avg_first,
    STBI__F_paeth_first
};

static unsigned char first_row_filter[5] = {
    STBI__F_none,
    STBI__F_sub,
    STBI__F_none,
    STBI__F_avg_first,
    STBI__F_paeth_first
};

static int _m3dstbi__paeth(int a, int b, int c) {
    int p = a + b - c;
    int pa = abs(p - a);
    int pb = abs(p - b);
    int pc = abs(p - c);
    if (pa <= pb && pa <= pc) return a;
    if (pb <= pc) return b;
    return c;
}

static unsigned char _m3dstbi__depth_scale_table[9] = { 0, 0xff, 0x55, 0, 0x11, 0, 0, 0, 0x01 };

static int _m3dstbi__create_png_image_raw(_m3dstbi__png *a, unsigned char *raw, _m3dstbi__uint32 raw_len, int out_n, _m3dstbi__uint32 x, _m3dstbi__uint32 y, int depth, int color) {
    int bytes = (depth == 16 ? 2 : 1);
    _m3dstbi__context *s = a->s;
    _m3dstbi__uint32 i, j, stride = x * out_n * bytes;
    _m3dstbi__uint32 img_len, img_width_bytes;
    int k;
    int img_n = s->img_n;

    int output_bytes = out_n * bytes;
    int filter_bytes = img_n * bytes;
    int width = x;

    STBI_ASSERT(out_n == s->img_n || out_n == s->img_n + 1);
    a->out = (unsigned char *)_m3dstbi__malloc_mad3(x, y, output_bytes, 0);
    if (!a->out) return _m3dstbi__err("outofmem", "Out of memory");

    if (!_m3dstbi__mad3sizes_valid(img_n, x, depth, 7)) return _m3dstbi__err("too large", "Corrupt PNG");
    img_width_bytes = (((img_n * x * depth) + 7) >> 3);
    img_len = (img_width_bytes + 1) * y;
    if (s->img_x == x && s->img_y == y) {
        if (raw_len != img_len) return _m3dstbi__err("not enough pixels", "Corrupt PNG");
    } else {
        if (raw_len < img_len) return _m3dstbi__err("not enough pixels", "Corrupt PNG");
    }

    for (j = 0; j < y; ++j) {
        unsigned char *cur = a->out + stride * j;
        unsigned char *prior = cur - stride;
        int filter = *raw++;

        if (filter > 4)
            return _m3dstbi__err("invalid filter", "Corrupt PNG");

        if (depth < 8) {
            STBI_ASSERT(img_width_bytes <= x);
            cur += x * out_n - img_width_bytes;
            filter_bytes = 1;
            width = img_width_bytes;
        }
        prior = cur - stride;

        if (j == 0) filter = first_row_filter[filter];

        for (k = 0; k < filter_bytes; ++k) {
            switch (filter) {
                case STBI__F_none: cur[k] = raw[k]; break;
                case STBI__F_sub: cur[k] = raw[k]; break;
                case STBI__F_up: cur[k] = STBI__BYTECAST(raw[k] + prior[k]); break;
                case STBI__F_avg: cur[k] = STBI__BYTECAST(raw[k] + (prior[k] >> 1)); break;
                case STBI__F_paeth: cur[k] = STBI__BYTECAST(raw[k] + _m3dstbi__paeth(0, prior[k], 0)); break;
                case STBI__F_avg_first: cur[k] = raw[k]; break;
                case STBI__F_paeth_first: cur[k] = raw[k]; break;
            }
        }

        if (depth == 8) {
            if (img_n != out_n)
                cur[img_n] = 255;
            raw += img_n;
            cur += out_n;
            prior += out_n;
        } else if (depth == 16) {
            if (img_n != out_n) {
                cur[filter_bytes] = 255;
                cur[filter_bytes + 1] = 255;
            }
            raw += filter_bytes;
            cur += output_bytes;
            prior += output_bytes;
        } else {
            raw += 1;
            cur += 1;
            prior += 1;
        }

        if (depth < 8 || img_n == out_n) {
            int nk = (width - 1) * filter_bytes;
#define STBI__CASE(f) \
    case f:           \
        for (k = 0; k < nk; ++k)
            switch (filter) {
                case STBI__F_none:
                    memcpy(cur, raw, nk);
                    break;
                    STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k - filter_bytes]); }
                    break;
                    STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); }
                    break;
                    STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k - filter_bytes]) >> 1)); }
                    break;
                    STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + _m3dstbi__paeth(cur[k - filter_bytes], prior[k], prior[k - filter_bytes])); }
                    break;
                    STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k - filter_bytes] >> 1)); }
                    break;
                    STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + _m3dstbi__paeth(cur[k - filter_bytes], 0, 0)); }
                    break;
            }
#undef STBI__CASE
            raw += nk;
        } else {
            STBI_ASSERT(img_n + 1 == out_n);
#define STBI__CASE(f)                                                                                                          \
    case f:                                                                                                                    \
        for (i = x - 1; i >= 1; --i, cur[filter_bytes] = 255, raw += filter_bytes, cur += output_bytes, prior += output_bytes) \
            for (k = 0; k < filter_bytes; ++k)
            switch (filter) {
                STBI__CASE(STBI__F_none) { cur[k] = raw[k]; }
                break;
                STBI__CASE(STBI__F_sub) { cur[k] = STBI__BYTECAST(raw[k] + cur[k - output_bytes]); }
                break;
                STBI__CASE(STBI__F_up) { cur[k] = STBI__BYTECAST(raw[k] + prior[k]); }
                break;
                STBI__CASE(STBI__F_avg) { cur[k] = STBI__BYTECAST(raw[k] + ((prior[k] + cur[k - output_bytes]) >> 1)); }
                break;
                STBI__CASE(STBI__F_paeth) { cur[k] = STBI__BYTECAST(raw[k] + _m3dstbi__paeth(cur[k - output_bytes], prior[k], prior[k - output_bytes])); }
                break;
                STBI__CASE(STBI__F_avg_first) { cur[k] = STBI__BYTECAST(raw[k] + (cur[k - output_bytes] >> 1)); }
                break;
                STBI__CASE(STBI__F_paeth_first) { cur[k] = STBI__BYTECAST(raw[k] + _m3dstbi__paeth(cur[k - output_bytes], 0, 0)); }
                break;
            }
#undef STBI__CASE

            if (depth == 16) {
                cur = a->out + stride * j;
                for (i = 0; i < x; ++i, cur += output_bytes) {
                    cur[filter_bytes + 1] = 255;
                }
            }
        }
    }

    if (depth < 8) {
        for (j = 0; j < y; ++j) {
            unsigned char *cur = a->out + stride * j;
            unsigned char *in = a->out + stride * j + x * out_n - img_width_bytes;
            unsigned char scale = (color == 0) ? _m3dstbi__depth_scale_table[depth] : 1;

            if (depth == 4) {
                for (k = x * img_n; k >= 2; k -= 2, ++in) {
                    *cur++ = scale * ((*in >> 4));
                    *cur++ = scale * ((*in) & 0x0f);
                }
                if (k > 0) *cur++ = scale * ((*in >> 4));
            } else if (depth == 2) {
                for (k = x * img_n; k >= 4; k -= 4, ++in) {
                    *cur++ = scale * ((*in >> 6));
                    *cur++ = scale * ((*in >> 4) & 0x03);
                    *cur++ = scale * ((*in >> 2) & 0x03);
                    *cur++ = scale * ((*in) & 0x03);
                }
                if (k > 0) *cur++ = scale * ((*in >> 6));
                if (k > 1) *cur++ = scale * ((*in >> 4) & 0x03);
                if (k > 2) *cur++ = scale * ((*in >> 2) & 0x03);
            } else if (depth == 1) {
                for (k = x * img_n; k >= 8; k -= 8, ++in) {
                    *cur++ = scale * ((*in >> 7));
                    *cur++ = scale * ((*in >> 6) & 0x01);
                    *cur++ = scale * ((*in >> 5) & 0x01);
                    *cur++ = scale * ((*in >> 4) & 0x01);
                    *cur++ = scale * ((*in >> 3) & 0x01);
                    *cur++ = scale * ((*in >> 2) & 0x01);
                    *cur++ = scale * ((*in >> 1) & 0x01);
                    *cur++ = scale * ((*in) & 0x01);
                }
                if (k > 0) *cur++ = scale * ((*in >> 7));
                if (k > 1) *cur++ = scale * ((*in >> 6) & 0x01);
                if (k > 2) *cur++ = scale * ((*in >> 5) & 0x01);
                if (k > 3) *cur++ = scale * ((*in >> 4) & 0x01);
                if (k > 4) *cur++ = scale * ((*in >> 3) & 0x01);
                if (k > 5) *cur++ = scale * ((*in >> 2) & 0x01);
                if (k > 6) *cur++ = scale * ((*in >> 1) & 0x01);
            }
            if (img_n != out_n) {
                int q;
                cur = a->out + stride * j;
                if (img_n == 1) {
                    for (q = x - 1; q >= 0; --q) {
                        cur[q * 2 + 1] = 255;
                        cur[q * 2 + 0] = cur[q];
                    }
                } else {
                    STBI_ASSERT(img_n == 3);
                    for (q = x - 1; q >= 0; --q) {
                        cur[q * 4 + 3] = 255;
                        cur[q * 4 + 2] = cur[q * 3 + 2];
                        cur[q * 4 + 1] = cur[q * 3 + 1];
                        cur[q * 4 + 0] = cur[q * 3 + 0];
                    }
                }
            }
        }
    } else if (depth == 16) {
        unsigned char *cur = a->out;
        _m3dstbi__uint16 *cur16 = (_m3dstbi__uint16 *)cur;

        for (i = 0; i < x * y * out_n; ++i, cur16++, cur += 2) {
            *cur16 = (cur[0] << 8) | cur[1];
        }
    }

    return 1;
}

static int _m3dstbi__create_png_image(_m3dstbi__png *a, unsigned char *image_data, _m3dstbi__uint32 image_data_len, int out_n, int depth, int color, int interlaced) {
    int bytes = (depth == 16 ? 2 : 1);
    int out_bytes = out_n * bytes;
    unsigned char *final;
    int p;
    if (!interlaced)
        return _m3dstbi__create_png_image_raw(a, image_data, image_data_len, out_n, a->s->img_x, a->s->img_y, depth, color);

    final = (unsigned char *)_m3dstbi__malloc_mad3(a->s->img_x, a->s->img_y, out_bytes, 0);
    for (p = 0; p < 7; ++p) {
        int xorig[] = { 0, 4, 0, 2, 0, 1, 0 };
        int yorig[] = { 0, 0, 4, 0, 2, 0, 1 };
        int xspc[] = { 8, 8, 4, 4, 2, 2, 1 };
        int yspc[] = { 8, 8, 8, 4, 4, 2, 2 };
        int i, j, x, y;
        x = (a->s->img_x - xorig[p] + xspc[p] - 1) / xspc[p];
        y = (a->s->img_y - yorig[p] + yspc[p] - 1) / yspc[p];
        if (x && y) {
            _m3dstbi__uint32 img_len = ((((a->s->img_n * x * depth) + 7) >> 3) + 1) * y;
            if (!_m3dstbi__create_png_image_raw(a, image_data, image_data_len, out_n, x, y, depth, color)) {
                STBI_FREE(final);
                return 0;
            }
            for (j = 0; j < y; ++j) {
                for (i = 0; i < x; ++i) {
                    int out_y = j * yspc[p] + yorig[p];
                    int out_x = i * xspc[p] + xorig[p];
                    memcpy(final + out_y * a->s->img_x * out_bytes + out_x * out_bytes,
                            a->out + (j * x + i) * out_bytes, out_bytes);
                }
            }
            STBI_FREE(a->out);
            image_data += img_len;
            image_data_len -= img_len;
        }
    }
    a->out = final;

    return 1;
}

static int _m3dstbi__compute_transparency(_m3dstbi__png *z, unsigned char* tc, int out_n) {
    _m3dstbi__context *s = z->s;
    _m3dstbi__uint32 i, pixel_count = s->img_x * s->img_y;
    unsigned char *p = z->out;

    STBI_ASSERT(out_n == 2 || out_n == 4);

    if (out_n == 2) {
        for (i = 0; i < pixel_count; ++i) {
            p[1] = (p[0] == tc[0] ? 0 : 255);
            p += 2;
        }
    } else {
        for (i = 0; i < pixel_count; ++i) {
            if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
                p[3] = 0;
            p += 4;
        }
    }
    return 1;
}

static int _m3dstbi__compute_transparency16(_m3dstbi__png *z, _m3dstbi__uint16 tc[3], int out_n) {
    _m3dstbi__context *s = z->s;
    _m3dstbi__uint32 i, pixel_count = s->img_x * s->img_y;
    _m3dstbi__uint16 *p = (_m3dstbi__uint16 *)z->out;

    STBI_ASSERT(out_n == 2 || out_n == 4);

    if (out_n == 2) {
        for (i = 0; i < pixel_count; ++i) {
            p[1] = (p[0] == tc[0] ? 0 : 65535);
            p += 2;
        }
    } else {
        for (i = 0; i < pixel_count; ++i) {
            if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
                p[3] = 0;
            p += 4;
        }
    }
    return 1;
}

static int _m3dstbi__expand_png_palette(_m3dstbi__png *a, unsigned char *palette, int len, int pal_img_n) {
    _m3dstbi__uint32 i, pixel_count = a->s->img_x * a->s->img_y;
    unsigned char *p, *temp_out, *orig = a->out;

    p = (unsigned char *)_m3dstbi__malloc_mad2(pixel_count, pal_img_n, 0);
    if (p == NULL) return _m3dstbi__err("outofmem", "Out of memory");

    temp_out = p;

    if (pal_img_n == 3) {
        for (i = 0; i < pixel_count; ++i) {
            int n = orig[i] * 4;
            p[0] = palette[n];
            p[1] = palette[n + 1];
            p[2] = palette[n + 2];
            p += 3;
        }
    } else {
        for (i = 0; i < pixel_count; ++i) {
            int n = orig[i] * 4;
            p[0] = palette[n];
            p[1] = palette[n + 1];
            p[2] = palette[n + 2];
            p[3] = palette[n + 3];
            p += 4;
        }
    }
    STBI_FREE(a->out);
    a->out = temp_out;

    STBI_NOTUSED(len);

    return 1;
}

#define STBI__PNG_TYPE(a, b, c, d) (((unsigned)(a) << 24) + ((unsigned)(b) << 16) + ((unsigned)(c) << 8) + (unsigned)(d))

static int _m3dstbi__parse_png_file(_m3dstbi__png *z, int scan, int req_comp) {
    unsigned char palette[1024], pal_img_n = 0;
    unsigned char has_trans = 0, tc[3] = {};
    _m3dstbi__uint16 tc16[3];
    _m3dstbi__uint32 ioff = 0, idata_limit = 0, i, pal_len = 0;
    int first = 1, k, interlace = 0, color = 0;
    _m3dstbi__context *s = z->s;

    z->expanded = NULL;
    z->idata = NULL;
    z->out = NULL;

    if (!_m3dstbi__check_png_header(s)) return 0;

    if (scan == STBI__SCAN_type) return 1;

    for (;;) {
        _m3dstbi__pngchunk c = _m3dstbi__get_chunk_header(s);
        switch (c.type) {
            case STBI__PNG_TYPE('C', 'g', 'B', 'I'):
                _m3dstbi__skip(s, c.length);
                break;
            case STBI__PNG_TYPE('I', 'H', 'D', 'R'): {
                int comp, filter;
                if (!first) return _m3dstbi__err("multiple IHDR", "Corrupt PNG");
                first = 0;
                if (c.length != 13) return _m3dstbi__err("bad IHDR len", "Corrupt PNG");
                s->img_x = _m3dstbi__get32be(s);
                if (s->img_x > (1 << 24)) return _m3dstbi__err("too large", "Very large image (corrupt?)");
                s->img_y = _m3dstbi__get32be(s);
                if (s->img_y > (1 << 24)) return _m3dstbi__err("too large", "Very large image (corrupt?)");
                z->depth = _m3dstbi__get8(s);
                if (z->depth != 1 && z->depth != 2 && z->depth != 4 && z->depth != 8 && z->depth != 16) return _m3dstbi__err("1/2/4/8/16-bit only", "PNG not supported: 1/2/4/8/16-bit only");
                color = _m3dstbi__get8(s);
                if (color > 6) return _m3dstbi__err("bad ctype", "Corrupt PNG");
                if (color == 3 && z->depth == 16) return _m3dstbi__err("bad ctype", "Corrupt PNG");
                if (color == 3)
                    pal_img_n = 3;
                else if (color & 1)
                    return _m3dstbi__err("bad ctype", "Corrupt PNG");
                comp = _m3dstbi__get8(s);
                if (comp) return _m3dstbi__err("bad comp method", "Corrupt PNG");
                filter = _m3dstbi__get8(s);
                if (filter) return _m3dstbi__err("bad filter method", "Corrupt PNG");
                interlace = _m3dstbi__get8(s);
                if (interlace > 1) return _m3dstbi__err("bad interlace method", "Corrupt PNG");
                if (!s->img_x || !s->img_y) return _m3dstbi__err("0-pixel image", "Corrupt PNG");
                if (!pal_img_n) {
                    s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
                    if ((1 << 30) / s->img_x / s->img_n < s->img_y) return _m3dstbi__err("too large", "Image too large to decode");
                    if (scan == STBI__SCAN_header) return 1;
                } else {
                    s->img_n = 1;
                    if ((1 << 30) / s->img_x / 4 < s->img_y) return _m3dstbi__err("too large", "Corrupt PNG");
                }
                break;
            }

            case STBI__PNG_TYPE('P', 'L', 'T', 'E'): {
                if (first) return _m3dstbi__err("first not IHDR", "Corrupt PNG");
                if (c.length > 256 * 3) return _m3dstbi__err("invalid PLTE", "Corrupt PNG");
                pal_len = c.length / 3;
                if (pal_len * 3 != c.length) return _m3dstbi__err("invalid PLTE", "Corrupt PNG");
                for (i = 0; i < pal_len; ++i) {
                    palette[i * 4 + 0] = _m3dstbi__get8(s);
                    palette[i * 4 + 1] = _m3dstbi__get8(s);
                    palette[i * 4 + 2] = _m3dstbi__get8(s);
                    palette[i * 4 + 3] = 255;
                }
                break;
            }

            case STBI__PNG_TYPE('t', 'R', 'N', 'S'): {
                if (first) return _m3dstbi__err("first not IHDR", "Corrupt PNG");
                if (z->idata) return _m3dstbi__err("tRNS after IDAT", "Corrupt PNG");
                if (pal_img_n) {
                    if (scan == STBI__SCAN_header) {
                        s->img_n = 4;
                        return 1;
                    }
                    if (pal_len == 0) return _m3dstbi__err("tRNS before PLTE", "Corrupt PNG");
                    if (c.length > pal_len) return _m3dstbi__err("bad tRNS len", "Corrupt PNG");
                    pal_img_n = 4;
                    for (i = 0; i < c.length; ++i)
                        palette[i * 4 + 3] = _m3dstbi__get8(s);
                } else {
                    if (!(s->img_n & 1)) return _m3dstbi__err("tRNS with alpha", "Corrupt PNG");
                    if (c.length != (_m3dstbi__uint32)s->img_n * 2) return _m3dstbi__err("bad tRNS len", "Corrupt PNG");
                    has_trans = 1;
                    if (z->depth == 16) {
                        for (k = 0; k < s->img_n; ++k)
                            tc16[k] = (_m3dstbi__uint16)_m3dstbi__get16be(s);
                    } else {
                        for (k = 0; k < s->img_n; ++k)
                            tc[k] = (unsigned char)(_m3dstbi__get16be(s) & 255) * _m3dstbi__depth_scale_table[z->depth];
                    }
                }
                break;
            }

            case STBI__PNG_TYPE('I', 'D', 'A', 'T'): {
                if (first) return _m3dstbi__err("first not IHDR", "Corrupt PNG");
                if (pal_img_n && !pal_len) return _m3dstbi__err("no PLTE", "Corrupt PNG");
                if (scan == STBI__SCAN_header) {
                    s->img_n = pal_img_n;
                    return 1;
                }
                if ((int)(ioff + c.length) < (int)ioff) return 0;
                if (ioff + c.length > idata_limit) {
                    _m3dstbi__uint32 idata_limit_old = idata_limit;
                    unsigned char *p;
                    if (idata_limit == 0) idata_limit = c.length > 4096 ? c.length : 4096;
                    while (ioff + c.length > idata_limit)
                        idata_limit *= 2;
                    STBI_NOTUSED(idata_limit_old);
                    p = (unsigned char *)STBI_REALLOC_SIZED(z->idata, idata_limit_old, idata_limit);
                    if (p == NULL) return _m3dstbi__err("outofmem", "Out of memory");
                    z->idata = p;
                }
                if (!_m3dstbi__getn(s, z->idata + ioff, c.length)) return _m3dstbi__err("outofdata", "Corrupt PNG");
                ioff += c.length;
                break;
            }

            case STBI__PNG_TYPE('I', 'E', 'N', 'D'): {
                _m3dstbi__uint32 raw_len, bpl;
                if (first) return _m3dstbi__err("first not IHDR", "Corrupt PNG");
                if (scan != STBI__SCAN_load) return 1;
                if (z->idata == NULL) return _m3dstbi__err("no IDAT", "Corrupt PNG");
                bpl = (s->img_x * z->depth + 7) / 8;
                raw_len = bpl * s->img_y * s->img_n /* pixels */ + s->img_y /* filter mode per row */;
                z->expanded = (unsigned char *)_m3dstbi_zlib_decode_malloc_guesssize_headerflag((char *)z->idata, ioff, raw_len, (int *)&raw_len, 1);
                if (z->expanded == NULL) return 0;
                STBI_FREE(z->idata);
                z->idata = NULL;
                if ((req_comp == s->img_n + 1 && req_comp != 3 && !pal_img_n) || has_trans)
                    s->img_out_n = s->img_n + 1;
                else
                    s->img_out_n = s->img_n;
                if (!_m3dstbi__create_png_image(z, z->expanded, raw_len, s->img_out_n, z->depth, color, interlace)) return 0;
                if (has_trans) {
                    if (z->depth == 16) {
                        if (!_m3dstbi__compute_transparency16(z, tc16, s->img_out_n)) return 0;
                    } else {
                        if (!_m3dstbi__compute_transparency(z, tc, s->img_out_n)) return 0;
                    }
                }
                if (pal_img_n) {
                    s->img_n = pal_img_n;
                    s->img_out_n = pal_img_n;
                    if (req_comp >= 3) s->img_out_n = req_comp;
                    if (!_m3dstbi__expand_png_palette(z, palette, pal_len, s->img_out_n))
                        return 0;
                } else if (has_trans) {
                    ++s->img_n;
                }
                STBI_FREE(z->expanded);
                z->expanded = NULL;
                return 1;
            }

            default:
                if (first) return _m3dstbi__err("first not IHDR", "Corrupt PNG");
                if ((c.type & (1 << 29)) == 0) {
                    return _m3dstbi__err("invalid_chunk", "PNG not supported: unknown PNG chunk type");
                }
                _m3dstbi__skip(s, c.length);
                break;
        }
        _m3dstbi__get32be(s);
    }
}

static void *_m3dstbi__do_png(_m3dstbi__png *p, int *x, int *y, int *n, int req_comp, _m3dstbi__result_info *ri) {
    void *result = NULL;
    if (req_comp < 0 || req_comp > 4) {
        _m3dstbi__err("bad req_comp", "Internal error");
        return NULL;
    }
    if (_m3dstbi__parse_png_file(p, STBI__SCAN_load, req_comp)) {
        if (p->depth < 8)
            ri->bits_per_channel = 8;
        else
            ri->bits_per_channel = p->depth;
        result = p->out;
        p->out = NULL;
        if (req_comp && req_comp != p->s->img_out_n) {
            if (ri->bits_per_channel == 8)
                result = _m3dstbi__convert_format((unsigned char *)result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
            else
                result = _m3dstbi__convert_format16((_m3dstbi__uint16 *)result, p->s->img_out_n, req_comp, p->s->img_x, p->s->img_y);
            p->s->img_out_n = req_comp;
            if (result == NULL) return result;
        }
        *x = p->s->img_x;
        *y = p->s->img_y;
        if (n) *n = p->s->img_n;
    }
    STBI_FREE(p->out);
    p->out = NULL;
    STBI_FREE(p->expanded);
    p->expanded = NULL;
    STBI_FREE(p->idata);
    p->idata = NULL;

    return result;
}

static void *_m3dstbi__png_load(_m3dstbi__context *s, int *x, int *y, int *comp, int req_comp, _m3dstbi__result_info *ri) {
    _m3dstbi__png p;
    p.s = s;
    return _m3dstbi__do_png(&p, x, y, comp, req_comp, ri);
}
#define stbi__context _m3dstbi__context
#define stbi__result_info _m3dstbi__result_info
#define stbi__png_load _m3dstbi__png_load
#define stbi_zlib_decode_malloc_guesssize_headerflag _m3dstbi_zlib_decode_malloc_guesssize_headerflag
#endif

#if defined(M3D_EXPORTER) && !defined(INCLUDE_STB_IMAGE_WRITE_H)
/* zlib_compressor from

   stb_image_write - v1.13 - public domain - http://nothings.org/stb/stb_image_write.h
*/
typedef unsigned char _m3dstbiw__uc;
typedef unsigned short _m3dstbiw__us;

typedef uint16_t _m3dstbiw__uint16;
typedef int16_t _m3dstbiw__int16;
typedef uint32_t _m3dstbiw__uint32;
typedef int32_t _m3dstbiw__int32;

#define STBIW_MALLOC(s) M3D_MALLOC(s)
#define STBIW_REALLOC(p, ns) M3D_REALLOC(p, ns)
#define STBIW_REALLOC_SIZED(p, oldsz, newsz) STBIW_REALLOC(p, newsz)
#define STBIW_FREE M3D_FREE
#define STBIW_MEMMOVE memmove
#define STBIW_UCHAR (uint8_t)
#define STBIW_ASSERT(x)
#define _m3dstbiw___sbraw(a) ((int *)(a)-2)
#define _m3dstbiw___sbm(a) _m3dstbiw___sbraw(a)[0]
#define _m3dstbiw___sbn(a) _m3dstbiw___sbraw(a)[1]

#define _m3dstbiw___sbneedgrow(a, n) ((a) == 0 || _m3dstbiw___sbn(a) + n >= _m3dstbiw___sbm(a))
#define _m3dstbiw___sbmaybegrow(a, n) (_m3dstbiw___sbneedgrow(a, (n)) ? _m3dstbiw___sbgrow(a, n) : 0)
#define _m3dstbiw___sbgrow(a, n) _m3dstbiw___sbgrowf((void **)&(a), (n), sizeof(*(a)))

#define _m3dstbiw___sbpush(a, v) (_m3dstbiw___sbmaybegrow(a, 1), (a)[_m3dstbiw___sbn(a)++] = (v))
#define _m3dstbiw___sbcount(a) ((a) ? _m3dstbiw___sbn(a) : 0)
#define _m3dstbiw___sbfree(a) ((a) ? STBIW_FREE(_m3dstbiw___sbraw(a)), 0 : 0)

static void *_m3dstbiw___sbgrowf(void **arr, int increment, int itemsize) {
    int m = *arr ? 2 * _m3dstbiw___sbm(*arr) + increment : increment + 1;
    void *p = STBIW_REALLOC_SIZED(*arr ? _m3dstbiw___sbraw(*arr) : 0, *arr ? (_m3dstbiw___sbm(*arr) * itemsize + sizeof(int) * 2) : 0, itemsize * m + sizeof(int) * 2);
    STBIW_ASSERT(p);
    if (p) {
        if (!*arr) ((int *)p)[1] = 0;
        *arr = (void *)((int *)p + 2);
        _m3dstbiw___sbm(*arr) = m;
    }
    return *arr;
}

static unsigned char *_m3dstbiw___zlib_flushf(unsigned char *data, unsigned int *bitbuffer, int *bitcount) {
    while (*bitcount >= 8) {
        _m3dstbiw___sbpush(data, STBIW_UCHAR(*bitbuffer));
        *bitbuffer >>= 8;
        *bitcount -= 8;
    }
    return data;
}

static int _m3dstbiw___zlib_bitrev(int code, int codebits) {
    int res = 0;
    while (codebits--) {
        res = (res << 1) | (code & 1);
        code >>= 1;
    }
    return res;
}

static unsigned int _m3dstbiw___zlib_countm(unsigned char *a, unsigned char *b, int limit) {
    int i;
    for (i = 0; i < limit && i < 258; ++i)
        if (a[i] != b[i]) break;
    return i;
}

static unsigned int _m3dstbiw___zhash(unsigned char *data) {
    _m3dstbiw__uint32 hash = data[0] + (data[1] << 8) + (data[2] << 16);
    hash ^= hash << 3;
    hash += hash >> 5;
    hash ^= hash << 4;
    hash += hash >> 17;
    hash ^= hash << 25;
    hash += hash >> 6;
    return hash;
}

#define _m3dstbiw___zlib_flush() (out = _m3dstbiw___zlib_flushf(out, &bitbuf, &bitcount))
#define _m3dstbiw___zlib_add(code, codebits) \
    (bitbuf |= (code) << bitcount, bitcount += (codebits), _m3dstbiw___zlib_flush())
#define _m3dstbiw___zlib_huffa(b, c) _m3dstbiw___zlib_add(_m3dstbiw___zlib_bitrev(b, c), c)
#define _m3dstbiw___zlib_huff1(n) _m3dstbiw___zlib_huffa(0x30 + (n), 8)
#define _m3dstbiw___zlib_huff2(n) _m3dstbiw___zlib_huffa(0x190 + (n)-144, 9)
#define _m3dstbiw___zlib_huff3(n) _m3dstbiw___zlib_huffa(0 + (n)-256, 7)
#define _m3dstbiw___zlib_huff4(n) _m3dstbiw___zlib_huffa(0xc0 + (n)-280, 8)
#define _m3dstbiw___zlib_huff(n) ((n) <= 143 ? _m3dstbiw___zlib_huff1(n) : (n) <= 255 ? _m3dstbiw___zlib_huff2(n) : (n) <= 279 ? _m3dstbiw___zlib_huff3(n) : _m3dstbiw___zlib_huff4(n))
#define _m3dstbiw___zlib_huffb(n) ((n) <= 143 ? _m3dstbiw___zlib_huff1(n) : _m3dstbiw___zlib_huff2(n))

#define _m3dstbiw___ZHASH 16384

unsigned char *_m3dstbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality) {
    static unsigned short lengthc[] = { 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 259 };
    static unsigned char lengtheb[] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0 };
    static unsigned short distc[] = { 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 32768 };
    static unsigned char disteb[] = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13 };
    unsigned int bitbuf = 0;
    int i, j, bitcount = 0;
    unsigned char *out = NULL;
    unsigned char ***hash_table = (unsigned char ***)STBIW_MALLOC(_m3dstbiw___ZHASH * sizeof(char **));
    if (hash_table == NULL)
        return NULL;
    if (quality < 5) quality = 5;

    _m3dstbiw___sbpush(out, 0x78);
    _m3dstbiw___sbpush(out, 0x5e);
    _m3dstbiw___zlib_add(1, 1);
    _m3dstbiw___zlib_add(1, 2);

    for (i = 0; i < _m3dstbiw___ZHASH; ++i)
        hash_table[i] = NULL;

    i = 0;
    while (i < data_len - 3) {
        int h = _m3dstbiw___zhash(data + i) & (_m3dstbiw___ZHASH - 1), best = 3;
        unsigned char *bestloc = 0;
        unsigned char **hlist = hash_table[h];
        int n = _m3dstbiw___sbcount(hlist);
        for (j = 0; j < n; ++j) {
            if (hlist[j] - data > i - 32768) {
                int d = _m3dstbiw___zlib_countm(hlist[j], data + i, data_len - i);
                if (d >= best) best = d, bestloc = hlist[j];
            }
        }
        if (hash_table[h] && _m3dstbiw___sbn(hash_table[h]) == 2 * quality) {
            STBIW_MEMMOVE(hash_table[h], hash_table[h] + quality, sizeof(hash_table[h][0]) * quality);
            _m3dstbiw___sbn(hash_table[h]) = quality;
        }
        _m3dstbiw___sbpush(hash_table[h], data + i);

        if (bestloc) {
            h = _m3dstbiw___zhash(data + i + 1) & (_m3dstbiw___ZHASH - 1);
            hlist = hash_table[h];
            n = _m3dstbiw___sbcount(hlist);
            for (j = 0; j < n; ++j) {
                if (hlist[j] - data > i - 32767) {
                    int e = _m3dstbiw___zlib_countm(hlist[j], data + i + 1, data_len - i - 1);
                    if (e > best) {
                        bestloc = NULL;
                        break;
                    }
                }
            }
        }

        if (bestloc) {
            int d = (int)(data + i - bestloc);
            STBIW_ASSERT(d <= 32767 && best <= 258);
            for (j = 0; best > lengthc[j + 1] - 1; ++j)
                ;
            _m3dstbiw___zlib_huff(j + 257);
            if (lengtheb[j]) _m3dstbiw___zlib_add(best - lengthc[j], lengtheb[j]);
            for (j = 0; d > distc[j + 1] - 1; ++j)
                ;
            _m3dstbiw___zlib_add(_m3dstbiw___zlib_bitrev(j, 5), 5);
            if (disteb[j]) _m3dstbiw___zlib_add(d - distc[j], disteb[j]);
            i += best;
        } else {
            _m3dstbiw___zlib_huffb(data[i]);
            ++i;
        }
    }
    for (; i < data_len; ++i)
        _m3dstbiw___zlib_huffb(data[i]);
    _m3dstbiw___zlib_huff(256);
    while (bitcount)
        _m3dstbiw___zlib_add(0, 1);

    for (i = 0; i < _m3dstbiw___ZHASH; ++i)
        (void)_m3dstbiw___sbfree(hash_table[i]);
    STBIW_FREE(hash_table);

    {
        unsigned int s1 = 1, s2 = 0;
        int blocklen = (int)(data_len % 5552);
        j = 0;
        while (j < data_len) {
            for (i = 0; i < blocklen; ++i)
                s1 += data[j + i], s2 += s1;
            s1 %= 65521, s2 %= 65521;
            j += blocklen;
            blocklen = 5552;
        }
        _m3dstbiw___sbpush(out, STBIW_UCHAR(s2 >> 8));
        _m3dstbiw___sbpush(out, STBIW_UCHAR(s2));
        _m3dstbiw___sbpush(out, STBIW_UCHAR(s1 >> 8));
        _m3dstbiw___sbpush(out, STBIW_UCHAR(s1));
    }
    *out_len = _m3dstbiw___sbn(out);
    STBIW_MEMMOVE(_m3dstbiw___sbraw(out), out, *out_len);
    return (unsigned char *)_m3dstbiw___sbraw(out);
}
#define stbi_zlib_compress _m3dstbi_zlib_compress
#else
unsigned char *_m3dstbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality);
#endif

#define M3D_CHUNKMAGIC(m, a, b, c, d) ((m)[0] == (a) && (m)[1] == (b) && (m)[2] == (c) && (m)[3] == (d))

#ifdef M3D_ASCII
#include <locale.h> /* sprintf and strtod cares about number locale */
#include <stdio.h> /* get sprintf */
#endif
#ifdef M3D_PROFILING
#include <sys/time.h>
#endif

#if !defined(M3D_NOIMPORTER) && defined(M3D_ASCII)
/* helper functions for the ASCII parser */
static char *_m3d_findarg(char *s) {
    while (s && *s && *s != ' ' && *s != '\t' && *s != '\r' && *s != '\n')
        s++;
    while (s && *s && (*s == ' ' || *s == '\t'))
        s++;
    return s;
}
static char *_m3d_findnl(char *s) {
    while (s && *s && *s != '\r' && *s != '\n')
        s++;
    if (*s == '\r') s++;
    if (*s == '\n') s++;
    return s;
}
static char *_m3d_gethex(char *s, uint32_t *ret) {
    if (*s == '#') s++;
    *ret = 0;
    for (; *s; s++) {
        if (*s >= '0' && *s <= '9') {
            *ret <<= 4;
            *ret += (uint32_t)(*s - '0');
        } else if (*s >= 'a' && *s <= 'f') {
            *ret <<= 4;
            *ret += (uint32_t)(*s - 'a' + 10);
        } else if (*s >= 'A' && *s <= 'F') {
            *ret <<= 4;
            *ret += (uint32_t)(*s - 'A' + 10);
        } else
            break;
    }
    return _m3d_findarg(s);
}
static char *_m3d_getint(char *s, uint32_t *ret) {
    char *e = s;
    if (!s || !*s || *s == '\r' || *s == '\n') return s;
    for (; *e >= '0' && *e <= '9'; e++)
        ;
    *ret = atoi(s);
    return e;
}
static char *_m3d_getfloat(char *s, M3D_FLOAT *ret) {
    char *e = s;
    if (!s || !*s || *s == '\r' || *s == '\n') return s;
    for (; *e == '-' || *e == '+' || *e == '.' || (*e >= '0' && *e <= '9') || *e == 'e' || *e == 'E'; e++)
        ;
    *ret = (M3D_FLOAT)strtod(s, NULL);
    return _m3d_findarg(e);
}
#endif
#if !defined(M3D_NODUP) && (!defined(M3D_NOIMPORTER) || defined(M3D_ASCII) || defined(M3D_EXPORTER))
/* helper function to create safe strings */
char *_m3d_safestr(char *in, int morelines) {
    char *out, *o, *i = in;
    int l;
    if (!in || !*in) {
        out = (char *)M3D_MALLOC(1);
        if (!out) return NULL;
        out[0] = 0;
    } else {
        for (o = in, l = 0; *o && ((morelines & 1) || (*o != '\r' && *o != '\n')) && l < 256; o++, l++)
            ;
        out = o = (char *)M3D_MALLOC(l + 1);
        if (!out) return NULL;
        while (*i == ' ' || *i == '\t' || *i == '\r' || (morelines && *i == '\n'))
            i++;
        for (; *i && (morelines || (*i != '\r' && *i != '\n')); i++) {
            if (*i == '\r') continue;
            if (*i == '\n') {
                if (morelines >= 3 && o > out && *(o - 1) == '\n') break;
                if (i > in && *(i - 1) == '\n') continue;
                if (morelines & 1) {
                    if (morelines == 1) *o++ = '\r';
                    *o++ = '\n';
                } else
                    break;
            } else if (*i == ' ' || *i == '\t') {
                *o++ = morelines ? ' ' : '_';
            } else
                *o++ = !morelines && (*i == '/' || *i == '\\') ? '_' : *i;
        }
        for (; o > out && (*(o - 1) == ' ' || *(o - 1) == '\t' || *(o - 1) == '\r' || *(o - 1) == '\n'); o--)
            ;
        *o = 0;
        out = (char *)M3D_REALLOC(out, (uintptr_t)o - (uintptr_t)out + 1);
    }
    return out;
}
#endif
#ifndef M3D_NOIMPORTER
/* helper function to load and decode/generate a texture */
M3D_INDEX _m3d_gettx(m3d_t *model, m3dread_t readfilecb, m3dfree_t freecb, char *fn) {
    unsigned int i, len = 0;
    unsigned char *buff = NULL;
    char *fn2;
#ifdef STBI__PNG_TYPE
    unsigned int w, h;
    stbi__context s;
    stbi__result_info ri;
#endif

    /* do we have loaded this texture already? */
    for (i = 0; i < model->numtexture; i++)
        if (!strcmp(fn, model->texture[i].name)) return i;
    /* see if it's inlined in the model */
    if (model->inlined) {
        for (i = 0; i < model->numinlined; i++)
            if (!strcmp(fn, model->inlined[i].name)) {
                buff = model->inlined[i].data;
                len = model->inlined[i].length;
                freecb = NULL;
                break;
            }
    }
    /* try to load from external source */
    if (!buff && readfilecb) {
        i = (unsigned int)strlen(fn);
        if (i < 5 || fn[i - 4] != '.') {
            fn2 = (char *)M3D_MALLOC(i + 5);
            if (!fn2) {
                model->errcode = M3D_ERR_ALLOC;
                return M3D_UNDEF;
            }
            memcpy(fn2, fn, i);
            memcpy(fn2 + i, ".png", 5);
            buff = (*readfilecb)(fn2, &len);
            M3D_FREE(fn2);
        }
        if (!buff) {
            buff = (*readfilecb)(fn, &len);
            if (!buff) return M3D_UNDEF;
        }
    }
    /* add to textures array */
    i = model->numtexture++;
    model->texture = (m3dtx_t *)M3D_REALLOC(model->texture, model->numtexture * sizeof(m3dtx_t));
    if (!model->texture) {
        if (buff && freecb) (*freecb)(buff);
        model->errcode = M3D_ERR_ALLOC;
        return M3D_UNDEF;
    }
    model->texture[i].name = fn;
    model->texture[i].w = model->texture[i].h = 0;
    model->texture[i].d = NULL;
    if (buff) {
        if (buff[0] == 0x89 && buff[1] == 'P' && buff[2] == 'N' && buff[3] == 'G') {
#ifdef STBI__PNG_TYPE
            s.read_from_callbacks = 0;
            s.img_buffer = s.img_buffer_original = (unsigned char *)buff;
            s.img_buffer_end = s.img_buffer_original_end = (unsigned char *)buff + len;
            /* don't use model->texture[i].w directly, it's a uint16_t */
            w = h = len = 0;
            ri.bits_per_channel = 8;
            model->texture[i].d = (uint8_t *)stbi__png_load(&s, (int *)&w, (int *)&h, (int *)&len, 0, &ri);
            model->texture[i].w = (uint16_t)w;
            model->texture[i].h = (uint16_t)h;
            model->texture[i].f = (uint8_t)len;
#endif
        } else {
#ifdef M3D_TX_INTERP
            if ((model->errcode = M3D_TX_INTERP(fn, buff, len, &model->texture[i])) != M3D_SUCCESS) {
                M3D_LOG("Unable to generate texture");
                M3D_LOG(fn);
            }
#else
            M3D_LOG("Unimplemented interpreter");
            M3D_LOG(fn);
#endif
        }
        if (freecb) (*freecb)(buff);
    }
    if (!model->texture[i].d)
        model->errcode = M3D_ERR_UNKIMG;
    return i;
}

/* helper function to load and generate a procedural surface */
void _m3d_getpr(m3d_t *model, _unused m3dread_t readfilecb, _unused m3dfree_t freecb, _unused char *fn) {
#ifdef M3D_PR_INTERP
    unsigned int i, len = 0;
    unsigned char *buff = readfilecb ? (*readfilecb)(fn, &len) : NULL;

    if (!buff && model->inlined) {
        for (i = 0; i < model->numinlined; i++)
            if (!strcmp(fn, model->inlined[i].name)) {
                buff = model->inlined[i].data;
                len = model->inlined[i].length;
                freecb = NULL;
                break;
            }
    }
    if (!buff || !len || (model->errcode = M3D_PR_INTERP(fn, buff, len, model)) != M3D_SUCCESS) {
        M3D_LOG("Unable to generate procedural surface");
        M3D_LOG(fn);
        model->errcode = M3D_ERR_UNKIMG;
    }
    if (freecb && buff) (*freecb)(buff);
#else
    (void)readfilecb;
    (void)freecb;
    (void)fn;
    M3D_LOG("Unimplemented interpreter");
    M3D_LOG(fn);
    model->errcode = M3D_ERR_UNIMPL;
#endif
}
/* helpers to read indices from data stream */
#define M3D_GETSTR(x)                                       \
    do {                                                    \
        offs = 0;                                           \
        data = _m3d_getidx(data, model->si_s, &offs);       \
        x = offs ? ((char *)model->raw + 16 + offs) : NULL; \
    } while (0)
_inline static unsigned char *_m3d_getidx(unsigned char *data, char type, M3D_INDEX *idx) {
    switch (type) {
        case 1:
            *idx = data[0] > 253 ? (int8_t)data[0] : data[0];
            data++;
            break;
        case 2:
            *idx = *((uint16_t *)data) > 65533 ? *((int16_t *)data) : *((uint16_t *)data);
            data += 2;
            break;
        case 4:
            *idx = *((int32_t *)data);
            data += 4;
            break;
    }
    return data;
}

#ifndef M3D_NOANIMATION
/* multiply 4 x 4 matrices. Do not use float *r[16] as argument, because some compilers misinterpret that as
 * 16 pointers each pointing to a float, but we need a single pointer to 16 floats. */
void _m3d_mul(M3D_FLOAT *r, M3D_FLOAT *a, M3D_FLOAT *b) {
    r[0] = b[0] * a[0] + b[4] * a[1] + b[8] * a[2] + b[12] * a[3];
    r[1] = b[1] * a[0] + b[5] * a[1] + b[9] * a[2] + b[13] * a[3];
    r[2] = b[2] * a[0] + b[6] * a[1] + b[10] * a[2] + b[14] * a[3];
    r[3] = b[3] * a[0] + b[7] * a[1] + b[11] * a[2] + b[15] * a[3];
    r[4] = b[0] * a[4] + b[4] * a[5] + b[8] * a[6] + b[12] * a[7];
    r[5] = b[1] * a[4] + b[5] * a[5] + b[9] * a[6] + b[13] * a[7];
    r[6] = b[2] * a[4] + b[6] * a[5] + b[10] * a[6] + b[14] * a[7];
    r[7] = b[3] * a[4] + b[7] * a[5] + b[11] * a[6] + b[15] * a[7];
    r[8] = b[0] * a[8] + b[4] * a[9] + b[8] * a[10] + b[12] * a[11];
    r[9] = b[1] * a[8] + b[5] * a[9] + b[9] * a[10] + b[13] * a[11];
    r[10] = b[2] * a[8] + b[6] * a[9] + b[10] * a[10] + b[14] * a[11];
    r[11] = b[3] * a[8] + b[7] * a[9] + b[11] * a[10] + b[15] * a[11];
    r[12] = b[0] * a[12] + b[4] * a[13] + b[8] * a[14] + b[12] * a[15];
    r[13] = b[1] * a[12] + b[5] * a[13] + b[9] * a[14] + b[13] * a[15];
    r[14] = b[2] * a[12] + b[6] * a[13] + b[10] * a[14] + b[14] * a[15];
    r[15] = b[3] * a[12] + b[7] * a[13] + b[11] * a[14] + b[15] * a[15];
}
/* calculate 4 x 4 matrix inverse */
void _m3d_inv(M3D_FLOAT *m) {
    M3D_FLOAT r[16];
    M3D_FLOAT det =
            m[0] * m[5] * m[10] * m[15] - m[0] * m[5] * m[11] * m[14] + m[0] * m[6] * m[11] * m[13] - m[0] * m[6] * m[9] * m[15] + m[0] * m[7] * m[9] * m[14] - m[0] * m[7] * m[10] * m[13] - m[1] * m[6] * m[11] * m[12] + m[1] * m[6] * m[8] * m[15] - m[1] * m[7] * m[8] * m[14] + m[1] * m[7] * m[10] * m[12] - m[1] * m[4] * m[10] * m[15] + m[1] * m[4] * m[11] * m[14] + m[2] * m[7] * m[8] * m[13] - m[2] * m[7] * m[9] * m[12] + m[2] * m[4] * m[9] * m[15] - m[2] * m[4] * m[11] * m[13] + m[2] * m[5] * m[11] * m[12] - m[2] * m[5] * m[8] * m[15] - m[3] * m[4] * m[9] * m[14] + m[3] * m[4] * m[10] * m[13] - m[3] * m[5] * m[10] * m[12] + m[3] * m[5] * m[8] * m[14] - m[3] * m[6] * m[8] * m[13] + m[3] * m[6] * m[9] * m[12];
    if (det == (M3D_FLOAT)0.0 || det == (M3D_FLOAT)-0.0)
        det = (M3D_FLOAT)1.0;
    else
        det = (M3D_FLOAT)1.0 / det;
    r[0] = det * (m[5] * (m[10] * m[15] - m[11] * m[14]) + m[6] * (m[11] * m[13] - m[9] * m[15]) + m[7] * (m[9] * m[14] - m[10] * m[13]));
    r[1] = -det * (m[1] * (m[10] * m[15] - m[11] * m[14]) + m[2] * (m[11] * m[13] - m[9] * m[15]) + m[3] * (m[9] * m[14] - m[10] * m[13]));
    r[2] = det * (m[1] * (m[6] * m[15] - m[7] * m[14]) + m[2] * (m[7] * m[13] - m[5] * m[15]) + m[3] * (m[5] * m[14] - m[6] * m[13]));
    r[3] = -det * (m[1] * (m[6] * m[11] - m[7] * m[10]) + m[2] * (m[7] * m[9] - m[5] * m[11]) + m[3] * (m[5] * m[10] - m[6] * m[9]));
    r[4] = -det * (m[4] * (m[10] * m[15] - m[11] * m[14]) + m[6] * (m[11] * m[12] - m[8] * m[15]) + m[7] * (m[8] * m[14] - m[10] * m[12]));
    r[5] = det * (m[0] * (m[10] * m[15] - m[11] * m[14]) + m[2] * (m[11] * m[12] - m[8] * m[15]) + m[3] * (m[8] * m[14] - m[10] * m[12]));
    r[6] = -det * (m[0] * (m[6] * m[15] - m[7] * m[14]) + m[2] * (m[7] * m[12] - m[4] * m[15]) + m[3] * (m[4] * m[14] - m[6] * m[12]));
    r[7] = det * (m[0] * (m[6] * m[11] - m[7] * m[10]) + m[2] * (m[7] * m[8] - m[4] * m[11]) + m[3] * (m[4] * m[10] - m[6] * m[8]));
    r[8] = det * (m[4] * (m[9] * m[15] - m[11] * m[13]) + m[5] * (m[11] * m[12] - m[8] * m[15]) + m[7] * (m[8] * m[13] - m[9] * m[12]));
    r[9] = -det * (m[0] * (m[9] * m[15] - m[11] * m[13]) + m[1] * (m[11] * m[12] - m[8] * m[15]) + m[3] * (m[8] * m[13] - m[9] * m[12]));
    r[10] = det * (m[0] * (m[5] * m[15] - m[7] * m[13]) + m[1] * (m[7] * m[12] - m[4] * m[15]) + m[3] * (m[4] * m[13] - m[5] * m[12]));
    r[11] = -det * (m[0] * (m[5] * m[11] - m[7] * m[9]) + m[1] * (m[7] * m[8] - m[4] * m[11]) + m[3] * (m[4] * m[9] - m[5] * m[8]));
    r[12] = -det * (m[4] * (m[9] * m[14] - m[10] * m[13]) + m[5] * (m[10] * m[12] - m[8] * m[14]) + m[6] * (m[8] * m[13] - m[9] * m[12]));
    r[13] = det * (m[0] * (m[9] * m[14] - m[10] * m[13]) + m[1] * (m[10] * m[12] - m[8] * m[14]) + m[2] * (m[8] * m[13] - m[9] * m[12]));
    r[14] = -det * (m[0] * (m[5] * m[14] - m[6] * m[13]) + m[1] * (m[6] * m[12] - m[4] * m[14]) + m[2] * (m[4] * m[13] - m[5] * m[12]));
    r[15] = det * (m[0] * (m[5] * m[10] - m[6] * m[9]) + m[1] * (m[6] * m[8] - m[4] * m[10]) + m[2] * (m[4] * m[9] - m[5] * m[8]));
    memcpy(m, &r, sizeof(r));
}
/* compose a coloumn major 4 x 4 matrix from vec3 position and vec4 orientation/rotation quaternion */
void _m3d_mat(M3D_FLOAT *r, m3dv_t *p, m3dv_t *q) {
    if (q->x == (M3D_FLOAT)0.0 && q->y == (M3D_FLOAT)0.0 && q->z >= (M3D_FLOAT)0.7071065 && q->z <= (M3D_FLOAT)0.7071075 &&
            q->w == (M3D_FLOAT)0.0) {
        r[1] = r[2] = r[4] = r[6] = r[8] = r[9] = (M3D_FLOAT)0.0;
        r[0] = r[5] = r[10] = (M3D_FLOAT)-1.0;
    } else {
        r[0] = 1 - 2 * (q->y * q->y + q->z * q->z);
        if (r[0] > -M3D_EPSILON && r[0] < M3D_EPSILON) r[0] = (M3D_FLOAT)0.0;
        r[1] = 2 * (q->x * q->y - q->z * q->w);
        if (r[1] > -M3D_EPSILON && r[1] < M3D_EPSILON) r[1] = (M3D_FLOAT)0.0;
        r[2] = 2 * (q->x * q->z + q->y * q->w);
        if (r[2] > -M3D_EPSILON && r[2] < M3D_EPSILON) r[2] = (M3D_FLOAT)0.0;
        r[4] = 2 * (q->x * q->y + q->z * q->w);
        if (r[4] > -M3D_EPSILON && r[4] < M3D_EPSILON) r[4] = (M3D_FLOAT)0.0;
        r[5] = 1 - 2 * (q->x * q->x + q->z * q->z);
        if (r[5] > -M3D_EPSILON && r[5] < M3D_EPSILON) r[5] = (M3D_FLOAT)0.0;
        r[6] = 2 * (q->y * q->z - q->x * q->w);
        if (r[6] > -M3D_EPSILON && r[6] < M3D_EPSILON) r[6] = (M3D_FLOAT)0.0;
        r[8] = 2 * (q->x * q->z - q->y * q->w);
        if (r[8] > -M3D_EPSILON && r[8] < M3D_EPSILON) r[8] = (M3D_FLOAT)0.0;
        r[9] = 2 * (q->y * q->z + q->x * q->w);
        if (r[9] > -M3D_EPSILON && r[9] < M3D_EPSILON) r[9] = (M3D_FLOAT)0.0;
        r[10] = 1 - 2 * (q->x * q->x + q->y * q->y);
        if (r[10] > -M3D_EPSILON && r[10] < M3D_EPSILON) r[10] = (M3D_FLOAT)0.0;
    }
    r[3] = p->x;
    r[7] = p->y;
    r[11] = p->z;
    r[12] = 0;
    r[13] = 0;
    r[14] = 0;
    r[15] = 1;
}
#endif
#if !defined(M3D_NOANIMATION) || !defined(M3D_NONORMALS)
/* portable fast inverse square root calculation. returns 1/sqrt(x) */
static M3D_FLOAT _m3d_rsq(M3D_FLOAT x) {
#ifdef M3D_DOUBLE
    return ((M3D_FLOAT)15.0 / (M3D_FLOAT)8.0) + ((M3D_FLOAT)-5.0 / (M3D_FLOAT)4.0) * x + ((M3D_FLOAT)3.0 / (M3D_FLOAT)8.0) * x * x;
#else
    /* John Carmack's */
    float x2 = x * 0.5f;
    *((uint32_t *)&x) = (0x5f3759df - (*((uint32_t *)&x) >> 1));
    return x * (1.5f - (x2 * x * x));
#endif
}
#endif

/**
 * Function to decode a Model 3D into in-memory format
 */
m3d_t *m3d_load(unsigned char *data, m3dread_t readfilecb, m3dfree_t freecb, m3d_t *mtllib) {
    unsigned char *end, *chunk, *buff, weights[8];
    unsigned int i, j, k, l, n, am, len = 0, reclen, offs;
    char *name, *lang;
    float f;
    m3d_t *model;
    M3D_INDEX mi;
    M3D_FLOAT w;
    m3dcd_t *cd;
    m3dtx_t *tx;
    m3dh_t *h;
    m3dm_t *m;
    m3da_t *a;
    m3di_t *t;
#ifndef M3D_NONORMALS
    char neednorm = 0;
    m3dv_t *norm = NULL, *v0, *v1, *v2, va, vb;
#endif
#ifndef M3D_NOANIMATION
    M3D_FLOAT r[16];
#endif
#if !defined(M3D_NOWEIGHTS) || !defined(M3D_NOANIMATION)
    m3db_t *b;
#endif
#ifndef M3D_NOWEIGHTS
    m3ds_t *sk;
#endif
#ifdef M3D_ASCII
    m3ds_t s;
    M3D_INDEX bi[M3D_BONEMAXLEVEL + 1], level;
    const char *ol;
    char *ptr, *pe, *fn;
#endif
#ifdef M3D_PROFILING
    struct timeval tv0, tv1, tvd;
    gettimeofday(&tv0, NULL);
#endif

    if (!data || (!M3D_CHUNKMAGIC(data, '3', 'D', 'M', 'O')
#ifdef M3D_ASCII
                         && !M3D_CHUNKMAGIC(data, '3', 'd', 'm', 'o')
#endif
                                 ))
        return NULL;
    model = (m3d_t *)M3D_MALLOC(sizeof(m3d_t));
    if (!model) {
        M3D_LOG("Out of memory");
        return NULL;
    }
    memset(model, 0, sizeof(m3d_t));

    if (mtllib) {
        model->nummaterial = mtllib->nummaterial;
        model->material = mtllib->material;
        model->numtexture = mtllib->numtexture;
        model->texture = mtllib->texture;
        model->flags |= M3D_FLG_MTLLIB;
    }
#ifdef M3D_ASCII
    /* ASCII variant? */
    if (M3D_CHUNKMAGIC(data, '3', 'd', 'm', 'o')) {
        model->errcode = M3D_ERR_BADFILE;
        model->flags |= M3D_FLG_FREESTR;
        model->raw = (m3dhdr_t *)data;
        ptr = (char *)data;
        ol = setlocale(LC_NUMERIC, NULL);
        setlocale(LC_NUMERIC, "C");
        /* parse header. Don't use sscanf, that's incredibly slow */
        ptr = _m3d_findarg(ptr);
        if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
        pe = _m3d_findnl(ptr);
        model->scale = (float)strtod(ptr, NULL);
        ptr = pe;
        if (model->scale <= (M3D_FLOAT)0.0) model->scale = (M3D_FLOAT)1.0;
        model->name = _m3d_safestr(ptr, 2);
        ptr = _m3d_findnl(ptr);
        if (!*ptr) goto asciiend;
        model->license = _m3d_safestr(ptr, 2);
        ptr = _m3d_findnl(ptr);
        if (!*ptr) goto asciiend;
        model->author = _m3d_safestr(ptr, 2);
        ptr = _m3d_findnl(ptr);
        if (!*ptr) goto asciiend;
        if (*ptr != '\r' && *ptr != '\n')
            model->desc = _m3d_safestr(ptr, 3);
        while (*ptr) {
            while (*ptr && *ptr != '\n')
                ptr++;
            ptr++;
            if (*ptr == '\r') ptr++;
            if (*ptr == '\n') break;
        }

        /* the main chunk reader loop */
        while (*ptr) {
            while (*ptr && (*ptr == '\r' || *ptr == '\n'))
                ptr++;
            if (!*ptr || (ptr[0] == 'E' && ptr[1] == 'n' && ptr[2] == 'd')) break;
            /* make sure there's at least one data row */
            pe = ptr;
            ptr = _m3d_findnl(ptr);
            if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
            /* Preview chunk */
            if (!memcmp(pe, "Preview", 7)) {
                if (readfilecb) {
                    pe = _m3d_safestr(ptr, 0);
                    if (!pe || !*pe) goto asciiend;
                    model->preview.data = (*readfilecb)(pe, &model->preview.length);
                    M3D_FREE(pe);
                }
                while (*ptr && *ptr != '\r' && *ptr != '\n')
                    ptr = _m3d_findnl(ptr);
            } else
                    /* texture map chunk */
                    if (!memcmp(pe, "Textmap", 7)) {
                if (model->tmap) {
                    M3D_LOG("More texture map chunks, should be unique");
                    goto asciiend;
                }
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    i = model->numtmap++;
                    model->tmap = (m3dti_t *)M3D_REALLOC(model->tmap, model->numtmap * sizeof(m3dti_t));
                    if (!model->tmap) goto memerr;
                    ptr = _m3d_getfloat(ptr, &model->tmap[i].u);
                    if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                    _m3d_getfloat(ptr, &model->tmap[i].v);
                    ptr = _m3d_findnl(ptr);
                }
            } else
                    /* vertex chunk */
                    if (!memcmp(pe, "Vertex", 6)) {
                if (model->vertex) {
                    M3D_LOG("More vertex chunks, should be unique");
                    goto asciiend;
                }
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    i = model->numvertex++;
                    model->vertex = (m3dv_t *)M3D_REALLOC(model->vertex, model->numvertex * sizeof(m3dv_t));
                    if (!model->vertex) goto memerr;
                    memset(&model->vertex[i], 0, sizeof(m3dv_t));
                    model->vertex[i].skinid = M3D_UNDEF;
                    model->vertex[i].color = 0;
                    model->vertex[i].w = (M3D_FLOAT)1.0;
                    ptr = _m3d_getfloat(ptr, &model->vertex[i].x);
                    if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                    ptr = _m3d_getfloat(ptr, &model->vertex[i].y);
                    if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                    ptr = _m3d_getfloat(ptr, &model->vertex[i].z);
                    if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                    ptr = _m3d_getfloat(ptr, &model->vertex[i].w);
                    if (!*ptr) goto asciiend;
                    if (*ptr == '#') {
                        ptr = _m3d_gethex(ptr, &model->vertex[i].color);
                        if (!*ptr) goto asciiend;
                    }
                    /* parse skin */
                    memset(&s, 0, sizeof(m3ds_t));
                    for (j = 0, w = (M3D_FLOAT)0.0; j < M3D_NUMBONE && *ptr && *ptr != '\r' && *ptr != '\n'; j++) {
                        ptr = _m3d_findarg(ptr);
                        if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                        ptr = _m3d_getint(ptr, &k);
                        s.boneid[j] = (M3D_INDEX)k;
                        if (*ptr == ':') {
                            ptr++;
                            ptr = _m3d_getfloat(ptr, &s.weight[j]);
                            w += s.weight[j];
                        } else if (!j)
                            s.weight[j] = (M3D_FLOAT)1.0;
                        if (!*ptr) goto asciiend;
                    }
                    if (s.boneid[0] != M3D_UNDEF && s.weight[0] > (M3D_FLOAT)0.0) {
                        if (w != (M3D_FLOAT)1.0 && w != (M3D_FLOAT)0.0)
                            for (j = 0; j < M3D_NUMBONE && s.weight[j] > (M3D_FLOAT)0.0; j++)
                                s.weight[j] /= w;
                        k = M3D_NOTDEFINED;
                        if (model->skin) {
                            for (j = 0; j < model->numskin; j++)
                                if (!memcmp(&model->skin[j], &s, sizeof(m3ds_t))) {
                                    k = j;
                                    break;
                                }
                        }
                        if (k == M3D_NOTDEFINED) {
                            k = model->numskin++;
                            model->skin = (m3ds_t *)M3D_REALLOC(model->skin, model->numskin * sizeof(m3ds_t));
                            memcpy(&model->skin[k], &s, sizeof(m3ds_t));
                        }
                        model->vertex[i].skinid = (M3D_INDEX)k;
                    }
                    ptr = _m3d_findnl(ptr);
                }
            } else
                    /* Skeleton, bone hierarchy */
                    if (!memcmp(pe, "Bones", 5)) {
                if (model->bone) {
                    M3D_LOG("More bones chunks, should be unique");
                    goto asciiend;
                }
                bi[0] = M3D_UNDEF;
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    i = model->numbone++;
                    model->bone = (m3db_t *)M3D_REALLOC(model->bone, model->numbone * sizeof(m3db_t));
                    if (!model->bone) goto memerr;
                    for (level = 0; *ptr == '/'; ptr++, level++)
                        ;
                    if (level > M3D_BONEMAXLEVEL || !*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                    bi[level + 1] = i;
                    model->bone[i].numweight = 0;
                    model->bone[i].weight = NULL;
                    model->bone[i].parent = bi[level];
                    ptr = _m3d_getint(ptr, &k);
                    ptr = _m3d_findarg(ptr);
                    if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                    model->bone[i].pos = (M3D_INDEX)k;
                    ptr = _m3d_getint(ptr, &k);
                    ptr = _m3d_findarg(ptr);
                    if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                    model->bone[i].ori = (M3D_INDEX)k;
                    model->vertex[k].skinid = M3D_INDEXMAX;
                    pe = _m3d_safestr(ptr, 0);
                    if (!pe || !*pe) goto asciiend;
                    model->bone[i].name = pe;
                    ptr = _m3d_findnl(ptr);
                }
            } else
                    /* material chunk */
                    if (!memcmp(pe, "Material", 8)) {
                pe = _m3d_findarg(pe);
                if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                pe = _m3d_safestr(pe, 0);
                if (!pe || !*pe) goto asciiend;
                for (i = 0; i < model->nummaterial; i++)
                    if (!strcmp(pe, model->material[i].name)) {
                        M3D_LOG("Multiple definitions for material");
                        M3D_LOG(pe);
                        M3D_FREE(pe);
                        pe = NULL;
                        while (*ptr && *ptr != '\r' && *ptr != '\n')
                            ptr = _m3d_findnl(ptr);
                        break;
                    }
                if (!pe) continue;
                i = model->nummaterial++;
                if (model->flags & M3D_FLG_MTLLIB) {
                    m = model->material;
                    model->material = (m3dm_t *)M3D_MALLOC(model->nummaterial * sizeof(m3dm_t));
                    if (!model->material) goto memerr;
                    memcpy(model->material, m, (model->nummaterial - 1) * sizeof(m3dm_t));
                    if (model->texture) {
                        tx = model->texture;
                        model->texture = (m3dtx_t *)M3D_MALLOC(model->numtexture * sizeof(m3dtx_t));
                        if (!model->texture) goto memerr;
                        memcpy(model->texture, tx, model->numtexture * sizeof(m3dm_t));
                    }
                    model->flags &= ~M3D_FLG_MTLLIB;
                } else {
                    model->material = (m3dm_t *)M3D_REALLOC(model->material, model->nummaterial * sizeof(m3dm_t));
                    if (!model->material) goto memerr;
                }
                m = &model->material[i];
                m->name = pe;
                m->numprop = 0;
                m->prop = NULL;
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    k = n = 256;
                    if (*ptr == 'm' && *(ptr + 1) == 'a' && *(ptr + 2) == 'p' && *(ptr + 3) == '_') {
                        k = m3dpf_map;
                        ptr += 4;
                    }
                    for (j = 0; j < sizeof(m3d_propertytypes) / sizeof(m3d_propertytypes[0]); j++)
                        if (!memcmp(ptr, m3d_propertytypes[j].key, strlen(m3d_propertytypes[j].key))) {
                            n = m3d_propertytypes[j].id;
                            if (k != m3dpf_map) k = m3d_propertytypes[j].format;
                            break;
                        }
                    if (n != 256 && k != 256) {
                        ptr = _m3d_findarg(ptr);
                        if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                        j = m->numprop++;
                        m->prop = (m3dp_t *)M3D_REALLOC(m->prop, m->numprop * sizeof(m3dp_t));
                        if (!m->prop) goto memerr;
                        m->prop[j].type = n + (k == m3dpf_map && n < 128 ? 128 : 0);
                        switch (k) {
                            case m3dpf_color: ptr = _m3d_gethex(ptr, &m->prop[j].value.color); break;
                            case m3dpf_uint8:
                            case m3dpf_uint16:
                            case m3dpf_uint32: ptr = _m3d_getint(ptr, &m->prop[j].value.num); break;
                            case m3dpf_float: ptr = _m3d_getfloat(ptr, &m->prop[j].value.fnum); break;
                            case m3dpf_map:
                                pe = _m3d_safestr(ptr, 0);
                                if (!pe || !*pe) goto asciiend;
                                m->prop[j].value.textureid = _m3d_gettx(model, readfilecb, freecb, pe);
                                if (model->errcode == M3D_ERR_ALLOC) {
                                    M3D_FREE(pe);
                                    goto memerr;
                                }
                                /* this error code only returned if readfilecb was specified */
                                if (m->prop[j].value.textureid == M3D_UNDEF) {
                                    M3D_LOG("Texture not found");
                                    M3D_LOG(pe);
                                    m->numprop--;
                                }
                                M3D_FREE(pe);
                                break;
                        }
                    } else {
                        M3D_LOG("Unknown material property in");
                        M3D_LOG(m->name);
                        model->errcode = M3D_ERR_UNKPROP;
                    }
                    ptr = _m3d_findnl(ptr);
                }
                if (!m->numprop) model->nummaterial--;
            } else
                    /* procedural */
                    if (!memcmp(pe, "Procedural", 10)) {
                pe = _m3d_safestr(ptr, 0);
                _m3d_getpr(model, readfilecb, freecb, pe);
                M3D_FREE(pe);
                while (*ptr && *ptr != '\r' && *ptr != '\n')
                    ptr = _m3d_findnl(ptr);
            } else
                    /* mesh */
                    if (!memcmp(pe, "Mesh", 4)) {
                mi = M3D_UNDEF;
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    if (*ptr == 'u') {
                        ptr = _m3d_findarg(ptr);
                        if (!*ptr) goto asciiend;
                        mi = M3D_UNDEF;
                        if (*ptr != '\r' && *ptr != '\n') {
                            pe = _m3d_safestr(ptr, 0);
                            if (!pe || !*pe) goto asciiend;
                            for (j = 0; j < model->nummaterial; j++)
                                if (!strcmp(pe, model->material[j].name)) {
                                    mi = (M3D_INDEX)j;
                                    break;
                                }
                            if (mi == M3D_UNDEF && !(model->flags & M3D_FLG_MTLLIB)) {
                                mi = model->nummaterial++;
                                model->material = (m3dm_t *)M3D_REALLOC(model->material, model->nummaterial * sizeof(m3dm_t));
                                if (!model->material) goto memerr;
                                model->material[mi].name = pe;
                                model->material[mi].numprop = 1;
                                model->material[mi].prop = NULL;
                            } else
                                M3D_FREE(pe);
                        }
                    } else {
                        i = model->numface++;
                        model->face = (m3df_t *)M3D_REALLOC(model->face, model->numface * sizeof(m3df_t));
                        if (!model->face) goto memerr;
                        memset(&model->face[i], 255, sizeof(m3df_t)); /* set all index to -1 by default */
                        model->face[i].materialid = mi;
                        /* hardcoded triangles. */
                        for (j = 0; j < 3; j++) {
                            /* vertex */
                            ptr = _m3d_getint(ptr, &k);
                            model->face[i].vertex[j] = (M3D_INDEX)k;
                            if (!*ptr) goto asciiend;
                            if (*ptr == '/') {
                                ptr++;
                                if (*ptr != '/') {
                                    /* texcoord */
                                    ptr = _m3d_getint(ptr, &k);
                                    model->face[i].texcoord[j] = (M3D_INDEX)k;
                                    if (!*ptr) goto asciiend;
                                }
                                if (*ptr == '/') {
                                    ptr++;
                                    /* normal */
                                    ptr = _m3d_getint(ptr, &k);
                                    model->face[i].normal[j] = (M3D_INDEX)k;
                                    if (!*ptr) goto asciiend;
                                }
                            }
#ifndef M3D_NONORMALS
                            if (model->face[i].normal[j] == M3D_UNDEF) neednorm = 1;
#endif
                            ptr = _m3d_findarg(ptr);
                        }
                    }
                    ptr = _m3d_findnl(ptr);
                }
            } else
                    /* mathematical shape */
                    if (!memcmp(pe, "Shape", 5)) {
                pe = _m3d_findarg(pe);
                if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                pe = _m3d_safestr(pe, 0);
                if (!pe || !*pe) goto asciiend;
                i = model->numshape++;
                model->shape = (m3dh_t *)M3D_REALLOC(model->shape, model->numshape * sizeof(m3ds_t));
                if (!model->shape) goto memerr;
                h = &model->shape[i];
                h->name = pe;
                h->group = M3D_UNDEF;
                h->numcmd = 0;
                h->cmd = NULL;
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    if (!memcmp(ptr, "group", 5)) {
                        ptr = _m3d_findarg(ptr);
                        ptr = _m3d_getint(ptr, &h->group);
                        ptr = _m3d_findnl(ptr);
                        if (h->group != M3D_UNDEF && h->group >= model->numbone) {
                            M3D_LOG("Unknown bone id as shape group in shape");
                            M3D_LOG(pe);
                            h->group = M3D_UNDEF;
                            model->errcode = M3D_ERR_SHPE;
                        }
                        continue;
                    }
                    for (cd = NULL, k = 0; k < (unsigned int)(sizeof(m3d_commandtypes) / sizeof(m3d_commandtypes[0])); k++) {
                        j = (unsigned int)strlen(m3d_commandtypes[k].key);
                        if (!memcmp(ptr, m3d_commandtypes[k].key, j) && (ptr[j] == ' ' || ptr[j] == '\r' || ptr[j] == '\n')) {
                            cd = &m3d_commandtypes[k];
                            break;
                        }
                    }
                    if (cd) {
                        j = h->numcmd++;
                        h->cmd = (m3dc_t *)M3D_REALLOC(h->cmd, h->numcmd * sizeof(m3dc_t));
                        if (!h->cmd) goto memerr;
                        h->cmd[j].type = k;
                        h->cmd[j].arg = (uint32_t *)M3D_MALLOC(cd->p * sizeof(uint32_t));
                        if (!h->cmd[j].arg) goto memerr;
                        memset(h->cmd[j].arg, 0, cd->p * sizeof(uint32_t));
                        for (k = n = 0, l = cd->p; k < l; k++) {
                            ptr = _m3d_findarg(ptr);
                            if (!*ptr) goto asciiend;
                            if (*ptr == '[') {
                                ptr = _m3d_findarg(ptr + 1);
                                if (!*ptr) goto asciiend;
                            }
                            if (*ptr == ']' || *ptr == '\r' || *ptr == '\n') break;
                            switch (cd->a[((k - n) % (cd->p - n)) + n]) {
                                case m3dcp_mi_t:
                                    mi = M3D_UNDEF;
                                    if (*ptr != '\r' && *ptr != '\n') {
                                        pe = _m3d_safestr(ptr, 0);
                                        if (!pe || !*pe) goto asciiend;
                                        for (n = 0; n < model->nummaterial; n++)
                                            if (!strcmp(pe, model->material[n].name)) {
                                                mi = (M3D_INDEX)n;
                                                break;
                                            }
                                        if (mi == M3D_UNDEF && !(model->flags & M3D_FLG_MTLLIB)) {
                                            mi = model->nummaterial++;
                                            model->material = (m3dm_t *)M3D_REALLOC(model->material,
                                                    model->nummaterial * sizeof(m3dm_t));
                                            if (!model->material) goto memerr;
                                            model->material[mi].name = pe;
                                            model->material[mi].numprop = 1;
                                            model->material[mi].prop = NULL;
                                        } else
                                            M3D_FREE(pe);
                                    }
                                    h->cmd[j].arg[k] = mi;
                                    break;
                                case m3dcp_vc_t:
                                    _m3d_getfloat(ptr, &w);
                                    h->cmd[j].arg[k] = *((uint32_t *)&w);
                                    break;
                                case m3dcp_va_t:
                                    ptr = _m3d_getint(ptr, &h->cmd[j].arg[k]);
                                    n = k + 1;
                                    l += (h->cmd[j].arg[k] - 1) * (cd->p - k - 1);
                                    h->cmd[j].arg = (uint32_t *)M3D_REALLOC(h->cmd[j].arg, l * sizeof(uint32_t));
                                    if (!h->cmd[j].arg) goto memerr;
                                    memset(&h->cmd[j].arg[k + 1], 0, (l - k - 1) * sizeof(uint32_t));
                                    break;
                                case m3dcp_qi_t:
                                    ptr = _m3d_getint(ptr, &h->cmd[j].arg[k]);
                                    model->vertex[h->cmd[i].arg[k]].skinid = M3D_INDEXMAX;
                                    break;
                                default:
                                    ptr = _m3d_getint(ptr, &h->cmd[j].arg[k]);
                                    break;
                            }
                        }
                    } else {
                        M3D_LOG("Unknown shape command in");
                        M3D_LOG(h->name);
                        model->errcode = M3D_ERR_UNKCMD;
                    }
                    ptr = _m3d_findnl(ptr);
                }
                if (!h->numcmd) model->numshape--;
            } else
                    /* annotation labels */
                    if (!memcmp(pe, "Labels", 6)) {
                pe = _m3d_findarg(pe);
                if (!*pe) goto asciiend;
                if (*pe == '\r' || *pe == '\n')
                    pe = NULL;
                else
                    pe = _m3d_safestr(pe, 0);
                k = 0;
                fn = NULL;
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    if (*ptr == 'c') {
                        ptr = _m3d_findarg(ptr);
                        if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                        ptr = _m3d_gethex(ptr, &k);
                    } else if (*ptr == 'l') {
                        ptr = _m3d_findarg(ptr);
                        if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                        fn = _m3d_safestr(ptr, 2);
                    } else {
                        i = model->numlabel++;
                        model->label = (m3dl_t *)M3D_REALLOC(model->label, model->numlabel * sizeof(m3dl_t));
                        if (!model->label) goto memerr;
                        model->label[i].name = pe;
                        model->label[i].lang = fn;
                        model->label[i].color = k;
                        ptr = _m3d_getint(ptr, &j);
                        model->label[i].vertexid = (M3D_INDEX)j;
                        ptr = _m3d_findarg(ptr);
                        if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                        model->label[i].text = _m3d_safestr(ptr, 2);
                    }
                    ptr = _m3d_findnl(ptr);
                }
            } else
                    /* action */
                    if (!memcmp(pe, "Action", 6)) {
                pe = _m3d_findarg(pe);
                if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                pe = _m3d_getint(pe, &k);
                pe = _m3d_findarg(pe);
                if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                pe = _m3d_safestr(pe, 0);
                if (!pe || !*pe) goto asciiend;
                i = model->numaction++;
                model->action = (m3da_t *)M3D_REALLOC(model->action, model->numaction * sizeof(m3da_t));
                if (!model->action) goto memerr;
                a = &model->action[i];
                a->name = pe;
                a->durationmsec = k;
                /* skip the first frame marker as there's always at least one frame */
                a->numframe = 1;
                a->frame = (m3dfr_t *)M3D_MALLOC(sizeof(m3dfr_t));
                if (!a->frame) goto memerr;
                a->frame[0].msec = 0;
                a->frame[0].numtransform = 0;
                a->frame[0].transform = NULL;
                i = 0;
                if (*ptr == 'f')
                    ptr = _m3d_findnl(ptr);
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    if (*ptr == 'f') {
                        i = a->numframe++;
                        a->frame = (m3dfr_t *)M3D_REALLOC(a->frame, a->numframe * sizeof(m3dfr_t));
                        if (!a->frame) goto memerr;
                        ptr = _m3d_findarg(ptr);
                        ptr = _m3d_getint(ptr, &a->frame[i].msec);
                        a->frame[i].numtransform = 0;
                        a->frame[i].transform = NULL;
                    } else {
                        j = a->frame[i].numtransform++;
                        a->frame[i].transform = (m3dtr_t *)M3D_REALLOC(a->frame[i].transform,
                                a->frame[i].numtransform * sizeof(m3dtr_t));
                        if (!a->frame[i].transform) goto memerr;
                        ptr = _m3d_getint(ptr, &k);
                        ptr = _m3d_findarg(ptr);
                        if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                        a->frame[i].transform[j].boneid = (M3D_INDEX)k;
                        ptr = _m3d_getint(ptr, &k);
                        ptr = _m3d_findarg(ptr);
                        if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                        a->frame[i].transform[j].pos = (M3D_INDEX)k;
                        ptr = _m3d_getint(ptr, &k);
                        if (!*ptr || *ptr == '\r' || *ptr == '\n') goto asciiend;
                        a->frame[i].transform[j].ori = (M3D_INDEX)k;
                        model->vertex[k].skinid = M3D_INDEXMAX;
                    }
                    ptr = _m3d_findnl(ptr);
                }
            } else
                    /* inlined assets chunk */
                    if (!memcmp(pe, "Assets", 6)) {
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    if (readfilecb) {
                        pe = _m3d_safestr(ptr, 2);
                        if (!pe || !*pe) goto asciiend;
                        i = model->numinlined++;
                        model->inlined = (m3di_t *)M3D_REALLOC(model->inlined, model->numinlined * sizeof(m3di_t));
                        if (!model->inlined) goto memerr;
                        t = &model->inlined[i];
                        model->inlined[i].data = (*readfilecb)(pe, &model->inlined[i].length);
                        if (model->inlined[i].data) {
                            fn = strrchr(pe, '.');
                            if (fn && (fn[1] == 'p' || fn[1] == 'P') && (fn[2] == 'n' || fn[2] == 'N') &&
                                    (fn[3] == 'g' || fn[3] == 'G')) *fn = 0;
                            fn = strrchr(pe, '/');
                            if (!fn) fn = strrchr(pe, '\\');
                            if (!fn)
                                fn = pe;
                            else
                                fn++;
                            model->inlined[i].name = _m3d_safestr(fn, 0);
                        } else
                            model->numinlined--;
                        M3D_FREE(pe);
                    }
                    ptr = _m3d_findnl(ptr);
                }
            } else
                    /* extra chunks */
                    if (!memcmp(pe, "Extra", 5)) {
                pe = _m3d_findarg(pe);
                if (!*pe || *pe == '\r' || *pe == '\n') goto asciiend;
                buff = (unsigned char *)_m3d_findnl(ptr);
                k = ((uint32_t)((uintptr_t)buff - (uintptr_t)ptr) / 3) + 1;
                i = model->numextra++;
                model->extra = (m3dchunk_t **)M3D_REALLOC(model->extra, model->numextra * sizeof(m3dchunk_t *));
                if (!model->extra) goto memerr;
                model->extra[i] = (m3dchunk_t *)M3D_MALLOC(k + sizeof(m3dchunk_t));
                if (!model->extra[i]) goto memerr;
                memcpy(&model->extra[i]->magic, pe, 4);
                model->extra[i]->length = sizeof(m3dchunk_t);
                pe = (char *)model->extra[i] + sizeof(m3dchunk_t);
                while (*ptr && *ptr != '\r' && *ptr != '\n') {
                    ptr = _m3d_gethex(ptr, &k);
                    *pe++ = (uint8_t)k;
                    model->extra[i]->length++;
                }
            } else
                goto asciiend;
        }
        model->errcode = M3D_SUCCESS;
    asciiend:
        setlocale(LC_NUMERIC, ol);
        goto postprocess;
    }
#endif
    /* Binary variant */
    if (!M3D_CHUNKMAGIC(data + 8, 'H', 'E', 'A', 'D')) {
        buff = (unsigned char *)stbi_zlib_decode_malloc_guesssize_headerflag((const char *)data + 8, ((m3dchunk_t *)data)->length - 8,
                4096, (int *)&len, 1);
        if (!buff || !len || !M3D_CHUNKMAGIC(buff, 'H', 'E', 'A', 'D')) {
            if (buff) M3D_FREE(buff);
            M3D_FREE(model);
            return NULL;
        }
        buff = (unsigned char *)M3D_REALLOC(buff, len);
        model->flags |= M3D_FLG_FREERAW; /* mark that we have to free the raw buffer */
        data = buff;
#ifdef M3D_PROFILING
        gettimeofday(&tv1, NULL);
        tvd.tv_sec = tv1.tv_sec - tv0.tv_sec;
        tvd.tv_usec = tv1.tv_usec - tv0.tv_usec;
        if (tvd.tv_usec < 0) {
            tvd.tv_sec--;
            tvd.tv_usec += 1000000L;
        }
        printf("  Deflate model   %ld.%06ld sec\n", tvd.tv_sec, tvd.tv_usec);
        memcpy(&tv0, &tv1, sizeof(struct timeval));
#endif
    } else {
        len = ((m3dhdr_t *)data)->length;
        data += 8;
    }
    model->raw = (m3dhdr_t *)data;
    end = data + len;

    /* parse header */
    data += sizeof(m3dhdr_t);
    M3D_LOG(data);
    model->name = (char *)data;
    for (; data < end && *data; data++) {
    };
    data++;
    model->license = (char *)data;
    for (; data < end && *data; data++) {
    };
    data++;
    model->author = (char *)data;
    for (; data < end && *data; data++) {
    };
    data++;
    model->desc = (char *)data;
    chunk = (unsigned char *)model->raw + model->raw->length;
    model->scale = (M3D_FLOAT)model->raw->scale;
    if (model->scale <= (M3D_FLOAT)0.0) model->scale = (M3D_FLOAT)1.0;
    model->vc_s = 1 << ((model->raw->types >> 0) & 3); /* vertex coordinate size */
    model->vi_s = 1 << ((model->raw->types >> 2) & 3); /* vertex index size */
    model->si_s = 1 << ((model->raw->types >> 4) & 3); /* string offset size */
    model->ci_s = 1 << ((model->raw->types >> 6) & 3); /* color index size */
    model->ti_s = 1 << ((model->raw->types >> 8) & 3); /* tmap index size */
    model->bi_s = 1 << ((model->raw->types >> 10) & 3); /* bone index size */
    model->nb_s = 1 << ((model->raw->types >> 12) & 3); /* number of bones per vertex */
    model->sk_s = 1 << ((model->raw->types >> 14) & 3); /* skin index size */
    model->fc_s = 1 << ((model->raw->types >> 16) & 3); /* frame counter size */
    model->hi_s = 1 << ((model->raw->types >> 18) & 3); /* shape index size */
    model->fi_s = 1 << ((model->raw->types >> 20) & 3); /* face index size */
    if (model->ci_s == 8) model->ci_s = 0; /* optional indices */
    if (model->ti_s == 8) model->ti_s = 0;
    if (model->bi_s == 8) model->bi_s = 0;
    if (model->sk_s == 8) model->sk_s = 0;
    if (model->fc_s == 8) model->fc_s = 0;
    if (model->hi_s == 8) model->hi_s = 0;
    if (model->fi_s == 8) model->fi_s = 0;

    /* variable limit checks */
    if (sizeof(M3D_FLOAT) == 4 && model->vc_s > 4) {
        M3D_LOG("Double precision coordinates not supported, truncating to float...");
        model->errcode = M3D_ERR_TRUNC;
    }
    if (sizeof(M3D_INDEX) == 2 && (model->vi_s > 2 || model->si_s > 2 || model->ci_s > 2 || model->ti_s > 2 ||
                                          model->bi_s > 2 || model->sk_s > 2 || model->fc_s > 2 || model->hi_s > 2 || model->fi_s > 2)) {
        M3D_LOG("32 bit indices not supported, unable to load model");
        M3D_FREE(model);
        return NULL;
    }
    if (model->vi_s > 4 || model->si_s > 4) {
        M3D_LOG("Invalid index size, unable to load model");
        M3D_FREE(model);
        return NULL;
    }
    if (model->nb_s > M3D_NUMBONE) {
        M3D_LOG("Model has more bones per vertex than what importer was configured to support");
        model->errcode = M3D_ERR_TRUNC;
    }

    /* look for inlined assets in advance, material and procedural chunks may need them */
    buff = chunk;
    while (buff < end && !M3D_CHUNKMAGIC(buff, 'O', 'M', 'D', '3')) {
        data = buff;
        len = ((m3dchunk_t *)data)->length;
        buff += len;
        if (len < sizeof(m3dchunk_t) || buff >= end) {
            M3D_LOG("Invalid chunk size");
            break;
        }
        len -= sizeof(m3dchunk_t) + model->si_s;

        /* inlined assets */
        if (M3D_CHUNKMAGIC(data, 'A', 'S', 'E', 'T') && len > 0) {
            M3D_LOG("Inlined asset");
            i = model->numinlined++;
            model->inlined = (m3di_t *)M3D_REALLOC(model->inlined, model->numinlined * sizeof(m3di_t));
            if (!model->inlined) {
            memerr:
                M3D_LOG("Out of memory");
                model->errcode = M3D_ERR_ALLOC;
                return model;
            }
            data += sizeof(m3dchunk_t);
            t = &model->inlined[i];
            M3D_GETSTR(t->name);
            M3D_LOG(t->name);
            t->data = (uint8_t *)data;
            t->length = len;
        }
    }

    /* parse chunks */
    while (chunk < end && !M3D_CHUNKMAGIC(chunk, 'O', 'M', 'D', '3')) {
        data = chunk;
        len = ((m3dchunk_t *)chunk)->length;
        chunk += len;
        if (len < sizeof(m3dchunk_t) || chunk >= end) {
            M3D_LOG("Invalid chunk size");
            break;
        }
        len -= sizeof(m3dchunk_t);

        /* preview chunk */
        if (M3D_CHUNKMAGIC(data, 'P', 'R', 'V', 'W') && len > 0) {
            model->preview.length = len;
            model->preview.data = data + sizeof(m3dchunk_t);
        } else
                /* color map */
                if (M3D_CHUNKMAGIC(data, 'C', 'M', 'A', 'P')) {
            M3D_LOG("Color map");
            if (model->cmap) {
                M3D_LOG("More color map chunks, should be unique");
                model->errcode = M3D_ERR_CMAP;
                continue;
            }
            if (!model->ci_s) {
                M3D_LOG("Color map chunk, shouldn't be any");
                model->errcode = M3D_ERR_CMAP;
                continue;
            }
            model->numcmap = len / sizeof(uint32_t);
            model->cmap = (uint32_t *)(data + sizeof(m3dchunk_t));
        } else
                /* texture map */
                if (M3D_CHUNKMAGIC(data, 'T', 'M', 'A', 'P')) {
            M3D_LOG("Texture map");
            if (model->tmap) {
                M3D_LOG("More texture map chunks, should be unique");
                model->errcode = M3D_ERR_TMAP;
                continue;
            }
            if (!model->ti_s) {
                M3D_LOG("Texture map chunk, shouldn't be any");
                model->errcode = M3D_ERR_TMAP;
                continue;
            }
            reclen = model->vc_s + model->vc_s;
            model->numtmap = len / reclen;
            model->tmap = (m3dti_t *)M3D_MALLOC(model->numtmap * sizeof(m3dti_t));
            if (!model->tmap) goto memerr;
            for (i = 0, data += sizeof(m3dchunk_t); data < chunk; i++) {
                switch (model->vc_s) {
                    case 1:
                        model->tmap[i].u = (M3D_FLOAT)(data[0]) / (M3D_FLOAT)255.0;
                        model->tmap[i].v = (M3D_FLOAT)(data[1]) / (M3D_FLOAT)255.0;
                        break;
                    case 2:
                        model->tmap[i].u = (M3D_FLOAT)(*((int16_t *)(data + 0))) / (M3D_FLOAT)65535.0;
                        model->tmap[i].v = (M3D_FLOAT)(*((int16_t *)(data + 2))) / (M3D_FLOAT)65535.0;
                        break;
                    case 4:
                        model->tmap[i].u = (M3D_FLOAT)(*((float *)(data + 0)));
                        model->tmap[i].v = (M3D_FLOAT)(*((float *)(data + 4)));
                        break;
                    case 8:
                        model->tmap[i].u = (M3D_FLOAT)(*((double *)(data + 0)));
                        model->tmap[i].v = (M3D_FLOAT)(*((double *)(data + 8)));
                        break;
                }
                data += reclen;
            }
        } else
                /* vertex list */
                if (M3D_CHUNKMAGIC(data, 'V', 'R', 'T', 'S')) {
            M3D_LOG("Vertex list");
            if (model->vertex) {
                M3D_LOG("More vertex chunks, should be unique");
                model->errcode = M3D_ERR_VRTS;
                continue;
            }
            if (model->ci_s && model->ci_s < 4 && !model->cmap) model->errcode = M3D_ERR_CMAP;
            reclen = model->ci_s + model->sk_s + 4 * model->vc_s;
            model->numvertex = len / reclen;
            model->vertex = (m3dv_t *)M3D_MALLOC(model->numvertex * sizeof(m3dv_t));
            if (!model->vertex) goto memerr;
            memset(model->vertex, 0, model->numvertex * sizeof(m3dv_t));
            for (i = 0, data += sizeof(m3dchunk_t); data < chunk && i < model->numvertex; i++) {
                switch (model->vc_s) {
                    case 1:
                        model->vertex[i].x = (M3D_FLOAT)((int8_t)data[0]) / (M3D_FLOAT)127.0;
                        model->vertex[i].y = (M3D_FLOAT)((int8_t)data[1]) / (M3D_FLOAT)127.0;
                        model->vertex[i].z = (M3D_FLOAT)((int8_t)data[2]) / (M3D_FLOAT)127.0;
                        model->vertex[i].w = (M3D_FLOAT)((int8_t)data[3]) / (M3D_FLOAT)127.0;
                        data += 4;
                        break;
                    case 2:
                        model->vertex[i].x = (M3D_FLOAT)(*((int16_t *)(data + 0))) / (M3D_FLOAT)32767.0;
                        model->vertex[i].y = (M3D_FLOAT)(*((int16_t *)(data + 2))) / (M3D_FLOAT)32767.0;
                        model->vertex[i].z = (M3D_FLOAT)(*((int16_t *)(data + 4))) / (M3D_FLOAT)32767.0;
                        model->vertex[i].w = (M3D_FLOAT)(*((int16_t *)(data + 6))) / (M3D_FLOAT)32767.0;
                        data += 8;
                        break;
                    case 4:
                        model->vertex[i].x = (M3D_FLOAT)(*((float *)(data + 0)));
                        model->vertex[i].y = (M3D_FLOAT)(*((float *)(data + 4)));
                        model->vertex[i].z = (M3D_FLOAT)(*((float *)(data + 8)));
                        model->vertex[i].w = (M3D_FLOAT)(*((float *)(data + 12)));
                        data += 16;
                        break;
                    case 8:
                        model->vertex[i].x = (M3D_FLOAT)(*((double *)(data + 0)));
                        model->vertex[i].y = (M3D_FLOAT)(*((double *)(data + 8)));
                        model->vertex[i].z = (M3D_FLOAT)(*((double *)(data + 16)));
                        model->vertex[i].w = (M3D_FLOAT)(*((double *)(data + 24)));
                        data += 32;
                        break;
                }
                switch (model->ci_s) {
                    case 1:
                        model->vertex[i].color = model->cmap ? model->cmap[data[0]] : 0;
                        data++;
                        break;
                    case 2:
                        model->vertex[i].color = model->cmap ? model->cmap[*((uint16_t *)data)] : 0;
                        data += 2;
                        break;
                    case 4:
                        model->vertex[i].color = *((uint32_t *)data);
                        data += 4;
                        break;
                        /* case 8: break; */
                }
                model->vertex[i].skinid = M3D_UNDEF;
                data = _m3d_getidx(data, model->sk_s, &model->vertex[i].skinid);
            }
        } else
                /* skeleton: bone hierarchy and skin */
                if (M3D_CHUNKMAGIC(data, 'B', 'O', 'N', 'E')) {
            M3D_LOG("Skeleton");
            if (model->bone) {
                M3D_LOG("More bone chunks, should be unique");
                model->errcode = M3D_ERR_BONE;
                continue;
            }
            if (!model->bi_s) {
                M3D_LOG("Bone chunk, shouldn't be any");
                model->errcode = M3D_ERR_BONE;
                continue;
            }
            if (!model->vertex) {
                M3D_LOG("No vertex chunk before bones");
                model->errcode = M3D_ERR_VRTS;
                break;
            }
            data += sizeof(m3dchunk_t);
            model->numbone = 0;
            data = _m3d_getidx(data, model->bi_s, &model->numbone);
            if (model->numbone) {
                model->bone = (m3db_t *)M3D_MALLOC(model->numbone * sizeof(m3db_t));
                if (!model->bone) goto memerr;
            }
            model->numskin = 0;
            data = _m3d_getidx(data, model->sk_s, &model->numskin);
            /* read bone hierarchy */
            for (i = 0; i < model->numbone; i++) {
                data = _m3d_getidx(data, model->bi_s, &model->bone[i].parent);
                M3D_GETSTR(model->bone[i].name);
                data = _m3d_getidx(data, model->vi_s, &model->bone[i].pos);
                data = _m3d_getidx(data, model->vi_s, &model->bone[i].ori);
                model->bone[i].numweight = 0;
                model->bone[i].weight = NULL;
            }
            /* read skin definitions */
            if (model->numskin) {
                model->skin = (m3ds_t *)M3D_MALLOC(model->numskin * sizeof(m3ds_t));
                if (!model->skin) goto memerr;
                for (i = 0; data < chunk && i < model->numskin; i++) {
                    for (j = 0; j < M3D_NUMBONE; j++) {
                        model->skin[i].boneid[j] = M3D_UNDEF;
                        model->skin[i].weight[j] = (M3D_FLOAT)0.0;
                    }
                    memset(&weights, 0, sizeof(weights));
                    if (model->nb_s == 1)
                        weights[0] = 255;
                    else {
                        memcpy(&weights, data, model->nb_s);
                        data += model->nb_s;
                    }
                    for (j = 0, w = (M3D_FLOAT)0.0; j < (unsigned int)model->nb_s; j++) {
                        if (weights[j]) {
                            if (j >= M3D_NUMBONE)
                                data += model->bi_s;
                            else {
                                model->skin[i].weight[j] = (M3D_FLOAT)(weights[j]) / (M3D_FLOAT)255.0;
                                w += model->skin[i].weight[j];
                                data = _m3d_getidx(data, model->bi_s, &model->skin[i].boneid[j]);
                            }
                        }
                    }
                    /* this can occur if model has more bones than what the importer is configured to handle */
                    if (w != (M3D_FLOAT)1.0 && w != (M3D_FLOAT)0.0) {
                        for (j = 0; j < M3D_NUMBONE; j++)
                            model->skin[i].weight[j] /= w;
                    }
                }
            }
        } else
                /* material */
                if (M3D_CHUNKMAGIC(data, 'M', 'T', 'R', 'L')) {
            data += sizeof(m3dchunk_t);
            M3D_GETSTR(name);
            M3D_LOG("Material");
            M3D_LOG(name);
            if (model->ci_s < 4 && !model->numcmap) model->errcode = M3D_ERR_CMAP;
            for (i = 0; i < model->nummaterial; i++)
                if (!strcmp(name, model->material[i].name)) {
                    model->errcode = M3D_ERR_MTRL;
                    M3D_LOG("Multiple definitions for material");
                    M3D_LOG(name);
                    name = NULL;
                    break;
                }
            if (name) {
                i = model->nummaterial++;
                if (model->flags & M3D_FLG_MTLLIB) {
                    m = model->material;
                    model->material = (m3dm_t *)M3D_MALLOC(model->nummaterial * sizeof(m3dm_t));
                    if (!model->material) goto memerr;
                    memcpy(model->material, m, (model->nummaterial - 1) * sizeof(m3dm_t));
                    if (model->texture) {
                        tx = model->texture;
                        model->texture = (m3dtx_t *)M3D_MALLOC(model->numtexture * sizeof(m3dtx_t));
                        if (!model->texture) goto memerr;
                        memcpy(model->texture, tx, model->numtexture * sizeof(m3dm_t));
                    }
                    model->flags &= ~M3D_FLG_MTLLIB;
                } else {
                    model->material = (m3dm_t *)M3D_REALLOC(model->material, model->nummaterial * sizeof(m3dm_t));
                    if (!model->material) goto memerr;
                }
                m = &model->material[i];
                m->numprop = 0;
                m->name = name;
                m->prop = (m3dp_t *)M3D_MALLOC((len / 2) * sizeof(m3dp_t));
                if (!m->prop) goto memerr;
                while (data < chunk) {
                    i = m->numprop++;
                    m->prop[i].type = *data++;
                    m->prop[i].value.num = 0;
                    if (m->prop[i].type >= 128)
                        k = m3dpf_map;
                    else {
                        for (k = 256, j = 0; j < sizeof(m3d_propertytypes) / sizeof(m3d_propertytypes[0]); j++)
                            if (m->prop[i].type == m3d_propertytypes[j].id) {
                                k = m3d_propertytypes[j].format;
                                break;
                            }
                    }
                    switch (k) {
                        case m3dpf_color:
                            switch (model->ci_s) {
                                case 1:
                                    m->prop[i].value.color = model->cmap ? model->cmap[data[0]] : 0;
                                    data++;
                                    break;
                                case 2:
                                    m->prop[i].value.color = model->cmap ? model->cmap[*((uint16_t *)data)] : 0;
                                    data += 2;
                                    break;
                                case 4:
                                    m->prop[i].value.color = *((uint32_t *)data);
                                    data += 4;
                                    break;
                            }
                            break;

                        case m3dpf_uint8: m->prop[i].value.num = *data++; break;
                        case m3dpf_uint16:
                            m->prop[i].value.num = *((uint16_t *)data);
                            data += 2;
                            break;
                        case m3dpf_uint32:
                            m->prop[i].value.num = *((uint32_t *)data);
                            data += 4;
                            break;
                        case m3dpf_float:
                            m->prop[i].value.fnum = *((float *)data);
                            data += 4;
                            break;

                        case m3dpf_map:
                            M3D_GETSTR(name);
                            m->prop[i].value.textureid = _m3d_gettx(model, readfilecb, freecb, name);
                            if (model->errcode == M3D_ERR_ALLOC) goto memerr;
                            /* this error code only returned if readfilecb was specified */
                            if (m->prop[i].value.textureid == M3D_UNDEF) {
                                M3D_LOG("Texture not found");
                                M3D_LOG(m->name);
                                m->numprop--;
                            }
                            break;

                        default:
                            M3D_LOG("Unknown material property in");
                            M3D_LOG(m->name);
                            model->errcode = M3D_ERR_UNKPROP;
                            data = chunk;
                            break;
                    }
                }
                m->prop = (m3dp_t *)M3D_REALLOC(m->prop, m->numprop * sizeof(m3dp_t));
                if (!m->prop) goto memerr;
            }
        } else
                /* face */
                if (M3D_CHUNKMAGIC(data, 'P', 'R', 'O', 'C')) {
            /* procedural surface */
            M3D_GETSTR(name);
            M3D_LOG("Procedural surface");
            M3D_LOG(name);
            _m3d_getpr(model, readfilecb, freecb, name);
        } else if (M3D_CHUNKMAGIC(data, 'M', 'E', 'S', 'H')) {
            M3D_LOG("Mesh data");
            /* mesh */
            data += sizeof(m3dchunk_t);
            mi = M3D_UNDEF;
            am = model->numface;
            while (data < chunk) {
                k = *data++;
                n = k >> 4;
                k &= 15;
                if (!n) {
                    /* use material */
                    mi = M3D_UNDEF;
                    M3D_GETSTR(name);
                    if (name) {
                        for (j = 0; j < model->nummaterial; j++)
                            if (!strcmp(name, model->material[j].name)) {
                                mi = (M3D_INDEX)j;
                                break;
                            }
                        if (mi == M3D_UNDEF) model->errcode = M3D_ERR_MTRL;
                    }
                    continue;
                }
                if (n != 3) {
                    M3D_LOG("Only triangle mesh supported for now");
                    model->errcode = M3D_ERR_UNKMESH;
                    return model;
                }
                i = model->numface++;
                if (model->numface > am) {
                    am = model->numface + 4095;
                    model->face = (m3df_t *)M3D_REALLOC(model->face, am * sizeof(m3df_t));
                    if (!model->face) goto memerr;
                }
                memset(&model->face[i], 255, sizeof(m3df_t)); /* set all index to -1 by default */
                model->face[i].materialid = mi;
                for (j = 0; j < n; j++) {
                    /* vertex */
                    data = _m3d_getidx(data, model->vi_s, &model->face[i].vertex[j]);
                    /* texcoord */
                    if (k & 1)
                        data = _m3d_getidx(data, model->ti_s, &model->face[i].texcoord[j]);
                    /* normal */
                    if (k & 2)
                        data = _m3d_getidx(data, model->vi_s, &model->face[i].normal[j]);
#ifndef M3D_NONORMALS
                    if (model->face[i].normal[j] == M3D_UNDEF) neednorm = 1;
#endif
                }
            }
            model->face = (m3df_t *)M3D_REALLOC(model->face, model->numface * sizeof(m3df_t));
        } else if (M3D_CHUNKMAGIC(data, 'S', 'H', 'P', 'E')) {
            /* mathematical shape */
            data += sizeof(m3dchunk_t);
            M3D_GETSTR(name);
            M3D_LOG("Mathematical Shape");
            M3D_LOG(name);
            i = model->numshape++;
            model->shape = (m3dh_t *)M3D_REALLOC(model->shape, model->numshape * sizeof(m3dh_t));
            if (!model->shape) goto memerr;
            h = &model->shape[i];
            h->numcmd = 0;
            h->cmd = NULL;
            h->name = name;
            h->group = M3D_UNDEF;
            data = _m3d_getidx(data, model->bi_s, &h->group);
            if (h->group != M3D_UNDEF && h->group >= model->numbone) {
                M3D_LOG("Unknown bone id as shape group in shape");
                M3D_LOG(name);
                h->group = M3D_UNDEF;
                model->errcode = M3D_ERR_SHPE;
            }
            while (data < chunk) {
                i = h->numcmd++;
                h->cmd = (m3dc_t *)M3D_REALLOC(h->cmd, h->numcmd * sizeof(m3dc_t));
                if (!h->cmd) goto memerr;
                h->cmd[i].type = *data++;
                if (h->cmd[i].type & 0x80) {
                    h->cmd[i].type &= 0x7F;
                    h->cmd[i].type |= (*data++ << 7);
                }
                if (h->cmd[i].type >= (unsigned int)(sizeof(m3d_commandtypes) / sizeof(m3d_commandtypes[0]))) {
                    M3D_LOG("Unknown shape command in");
                    M3D_LOG(h->name);
                    model->errcode = M3D_ERR_UNKCMD;
                    break;
                }
                cd = &m3d_commandtypes[h->cmd[i].type];
                h->cmd[i].arg = (uint32_t *)M3D_MALLOC(cd->p * sizeof(uint32_t));
                if (!h->cmd[i].arg) goto memerr;
                memset(h->cmd[i].arg, 0, cd->p * sizeof(uint32_t));
                for (k = n = 0, l = cd->p; k < l; k++)
                    switch (cd->a[((k - n) % (cd->p - n)) + n]) {
                        case m3dcp_mi_t:
                            h->cmd[i].arg[k] = M3D_NOTDEFINED;
                            M3D_GETSTR(name);
                            if (name) {
                                for (n = 0; n < model->nummaterial; n++)
                                    if (!strcmp(name, model->material[n].name)) {
                                        h->cmd[i].arg[k] = n;
                                        break;
                                    }
                                if (h->cmd[i].arg[k] == M3D_NOTDEFINED) model->errcode = M3D_ERR_MTRL;
                            }
                            break;
                        case m3dcp_vc_t:
                            f = 0.0f;
                            switch (model->vc_s) {
                                case 1: f = (float)((int8_t)data[0]) / 127; break;
                                case 2: f = (float)(*((int16_t *)(data + 0))) / 32767; break;
                                case 4: f = (float)(*((float *)(data + 0))); break;
                                case 8: f = (float)(*((double *)(data + 0))); break;
                            }
                            h->cmd[i].arg[k] = *((uint32_t *)&f);
                            data += model->vc_s;
                            break;
                        case m3dcp_hi_t: data = _m3d_getidx(data, model->hi_s, &h->cmd[i].arg[k]); break;
                        case m3dcp_fi_t: data = _m3d_getidx(data, model->fi_s, &h->cmd[i].arg[k]); break;
                        case m3dcp_ti_t: data = _m3d_getidx(data, model->ti_s, &h->cmd[i].arg[k]); break;
                        case m3dcp_qi_t:
                        case m3dcp_vi_t: data = _m3d_getidx(data, model->vi_s, &h->cmd[i].arg[k]); break;
                        case m3dcp_i1_t: data = _m3d_getidx(data, 1, &h->cmd[i].arg[k]); break;
                        case m3dcp_i2_t: data = _m3d_getidx(data, 2, &h->cmd[i].arg[k]); break;
                        case m3dcp_i4_t: data = _m3d_getidx(data, 4, &h->cmd[i].arg[k]); break;
                        case m3dcp_va_t:
                            data = _m3d_getidx(data, 4, &h->cmd[i].arg[k]);
                            n = k + 1;
                            l += (h->cmd[i].arg[k] - 1) * (cd->p - k - 1);
                            h->cmd[i].arg = (uint32_t *)M3D_REALLOC(h->cmd[i].arg, l * sizeof(uint32_t));
                            if (!h->cmd[i].arg) goto memerr;
                            memset(&h->cmd[i].arg[k + 1], 0, (l - k - 1) * sizeof(uint32_t));
                            break;
                    }
            }
        } else
                /* annotation label list */
                if (M3D_CHUNKMAGIC(data, 'L', 'B', 'L', 'S')) {
            data += sizeof(m3dchunk_t);
            M3D_GETSTR(name);
            M3D_GETSTR(lang);
            M3D_LOG("Label list");
            if (name) {
                M3D_LOG(name);
            }
            if (lang) {
                M3D_LOG(lang);
            }
            if (model->ci_s && model->ci_s < 4 && !model->cmap) model->errcode = M3D_ERR_CMAP;
            k = 0;
            switch (model->ci_s) {
                case 1:
                    k = model->cmap ? model->cmap[data[0]] : 0;
                    data++;
                    break;
                case 2:
                    k = model->cmap ? model->cmap[*((uint16_t *)data)] : 0;
                    data += 2;
                    break;
                case 4:
                    k = *((uint32_t *)data);
                    data += 4;
                    break;
                    /* case 8: break; */
            }
            reclen = model->vi_s + model->si_s;
            i = model->numlabel;
            model->numlabel += len / reclen;
            model->label = (m3dl_t *)M3D_REALLOC(model->label, model->numlabel * sizeof(m3dl_t));
            if (!model->label) goto memerr;
            memset(&model->label[i], 0, (model->numlabel - i) * sizeof(m3dl_t));
            for (; data < chunk && i < model->numlabel; i++) {
                model->label[i].name = name;
                model->label[i].lang = lang;
                model->label[i].color = k;
                data = _m3d_getidx(data, model->vi_s, &model->label[i].vertexid);
                M3D_GETSTR(model->label[i].text);
            }
        } else
                /* action */
                if (M3D_CHUNKMAGIC(data, 'A', 'C', 'T', 'N')) {
            M3D_LOG("Action");
            i = model->numaction++;
            model->action = (m3da_t *)M3D_REALLOC(model->action, model->numaction * sizeof(m3da_t));
            if (!model->action) goto memerr;
            a = &model->action[i];
            data += sizeof(m3dchunk_t);
            M3D_GETSTR(a->name);
            M3D_LOG(a->name);
            a->numframe = *((uint16_t *)data);
            data += 2;
            if (a->numframe < 1) {
                model->numaction--;
            } else {
                a->durationmsec = *((uint32_t *)data);
                data += 4;
                a->frame = (m3dfr_t *)M3D_MALLOC(a->numframe * sizeof(m3dfr_t));
                if (!a->frame) goto memerr;
                for (i = 0; data < chunk && i < a->numframe; i++) {
                    a->frame[i].msec = *((uint32_t *)data);
                    data += 4;
                    a->frame[i].numtransform = 0;
                    a->frame[i].transform = NULL;
                    data = _m3d_getidx(data, model->fc_s, &a->frame[i].numtransform);
                    if (a->frame[i].numtransform > 0) {
                        a->frame[i].transform = (m3dtr_t *)M3D_MALLOC(a->frame[i].numtransform * sizeof(m3dtr_t));
                        for (j = 0; j < a->frame[i].numtransform; j++) {
                            data = _m3d_getidx(data, model->bi_s, &a->frame[i].transform[j].boneid);
                            data = _m3d_getidx(data, model->vi_s, &a->frame[i].transform[j].pos);
                            data = _m3d_getidx(data, model->vi_s, &a->frame[i].transform[j].ori);
                        }
                    }
                }
            }
        } else {
            i = model->numextra++;
            model->extra = (m3dchunk_t **)M3D_REALLOC(model->extra, model->numextra * sizeof(m3dchunk_t *));
            if (!model->extra) goto memerr;
            model->extra[i] = (m3dchunk_t *)data;
        }
    }
    /* calculate normals, normalize skin weights, create bone/vertex cross-references and calculate transform matrices */
#ifdef M3D_ASCII
postprocess:
#endif
    if (model) {
        M3D_LOG("Post-process");
#ifdef M3D_PROFILING
        gettimeofday(&tv1, NULL);
        tvd.tv_sec = tv1.tv_sec - tv0.tv_sec;
        tvd.tv_usec = tv1.tv_usec - tv0.tv_usec;
        if (tvd.tv_usec < 0) {
            tvd.tv_sec--;
            tvd.tv_usec += 1000000L;
        }
        printf("  Parsing chunks  %ld.%06ld sec\n", tvd.tv_sec, tvd.tv_usec);
#endif
#ifndef M3D_NONORMALS
        if (model->numface && model->face && neednorm) {
            /* if they are missing, calculate triangle normals into a temporary buffer */
            norm = (m3dv_t *)M3D_MALLOC(model->numface * sizeof(m3dv_t));
            if (!norm) goto memerr;
            for (i = 0, n = model->numvertex; i < model->numface; i++)
                if (model->face[i].normal[0] == M3D_UNDEF) {
                    v0 = &model->vertex[model->face[i].vertex[0]];
                    v1 = &model->vertex[model->face[i].vertex[1]];
                    v2 = &model->vertex[model->face[i].vertex[2]];
                    va.x = v1->x - v0->x;
                    va.y = v1->y - v0->y;
                    va.z = v1->z - v0->z;
                    vb.x = v2->x - v0->x;
                    vb.y = v2->y - v0->y;
                    vb.z = v2->z - v0->z;
                    v0 = &norm[i];
                    v0->x = (va.y * vb.z) - (va.z * vb.y);
                    v0->y = (va.z * vb.x) - (va.x * vb.z);
                    v0->z = (va.x * vb.y) - (va.y * vb.x);
                    w = _m3d_rsq((v0->x * v0->x) + (v0->y * v0->y) + (v0->z * v0->z));
                    v0->x *= w;
                    v0->y *= w;
                    v0->z *= w;
                    model->face[i].normal[0] = model->face[i].vertex[0] + n;
                    model->face[i].normal[1] = model->face[i].vertex[1] + n;
                    model->face[i].normal[2] = model->face[i].vertex[2] + n;
                }
            /* this is the fast way, we don't care if a normal is repeated in model->vertex */
            M3D_LOG("Generating normals");
            model->flags |= M3D_FLG_GENNORM;
            model->numvertex <<= 1;
            model->vertex = (m3dv_t *)M3D_REALLOC(model->vertex, model->numvertex * sizeof(m3dv_t));
            if (!model->vertex) goto memerr;
            memset(&model->vertex[n], 0, n * sizeof(m3dv_t));
            for (i = 0; i < model->numface; i++)
                for (j = 0; j < 3; j++) {
                    v0 = &model->vertex[model->face[i].vertex[j] + n];
                    v0->x += norm[i].x;
                    v0->y += norm[i].y;
                    v0->z += norm[i].z;
                }
            /* for each vertex, take the average of the temporary normals and use that */
            for (i = 0, v0 = &model->vertex[n]; i < n; i++, v0++) {
                w = _m3d_rsq((v0->x * v0->x) + (v0->y * v0->y) + (v0->z * v0->z));
                v0->x *= w;
                v0->y *= w;
                v0->z *= w;
                v0->skinid = M3D_UNDEF;
            }
            M3D_FREE(norm);
        }
#endif
        if (model->numbone && model->bone && model->numskin && model->skin && model->numvertex && model->vertex) {
#ifndef M3D_NOWEIGHTS
            M3D_LOG("Generating weight cross-reference");
            for (i = 0; i < model->numvertex; i++) {
                if (model->vertex[i].skinid < model->numskin) {
                    sk = &model->skin[model->vertex[i].skinid];
                    w = (M3D_FLOAT)0.0;
                    for (j = 0; j < M3D_NUMBONE && sk->boneid[j] != M3D_UNDEF && sk->weight[j] > (M3D_FLOAT)0.0; j++)
                        w += sk->weight[j];
                    for (j = 0; j < M3D_NUMBONE && sk->boneid[j] != M3D_UNDEF && sk->weight[j] > (M3D_FLOAT)0.0; j++) {
                        sk->weight[j] /= w;
                        b = &model->bone[sk->boneid[j]];
                        k = b->numweight++;
                        b->weight = (m3dw_t *)M3D_REALLOC(b->weight, b->numweight * sizeof(m3da_t));
                        if (!b->weight) goto memerr;
                        b->weight[k].vertexid = i;
                        b->weight[k].weight = sk->weight[j];
                    }
                }
            }
#endif
#ifndef M3D_NOANIMATION
            M3D_LOG("Calculating bone transformation matrices");
            for (i = 0; i < model->numbone; i++) {
                b = &model->bone[i];
                if (model->bone[i].parent == M3D_UNDEF) {
                    _m3d_mat((M3D_FLOAT *)&b->mat4, &model->vertex[b->pos], &model->vertex[b->ori]);
                } else {
                    _m3d_mat((M3D_FLOAT *)&r, &model->vertex[b->pos], &model->vertex[b->ori]);
                    _m3d_mul((M3D_FLOAT *)&b->mat4, (M3D_FLOAT *)&model->bone[b->parent].mat4, (M3D_FLOAT *)&r);
                }
            }
            for (i = 0; i < model->numbone; i++)
                _m3d_inv((M3D_FLOAT *)&model->bone[i].mat4);
#endif
        }
#ifdef M3D_PROFILING
        gettimeofday(&tv0, NULL);
        tvd.tv_sec = tv0.tv_sec - tv1.tv_sec;
        tvd.tv_usec = tv0.tv_usec - tv1.tv_usec;
        if (tvd.tv_usec < 0) {
            tvd.tv_sec--;
            tvd.tv_usec += 1000000L;
        }
        printf("  Post-process    %ld.%06ld sec\n", tvd.tv_sec, tvd.tv_usec);
#endif
    }
    return model;
}

/**
 * Calculates skeletons for animation frames, returns a working copy (should be freed after use)
 */
m3dtr_t *m3d_frame(m3d_t *model, M3D_INDEX actionid, M3D_INDEX frameid, m3dtr_t *skeleton) {
    unsigned int i;
    M3D_INDEX s = frameid;
    m3dfr_t *fr;

    if (!model || !model->numbone || !model->bone || (actionid != M3D_UNDEF && (!model->action || actionid >= model->numaction || frameid >= model->action[actionid].numframe))) {
        model->errcode = M3D_ERR_UNKFRAME;
        return skeleton;
    }
    model->errcode = M3D_SUCCESS;
    if (!skeleton) {
        skeleton = (m3dtr_t *)M3D_MALLOC(model->numbone * sizeof(m3dtr_t));
        if (!skeleton) {
            model->errcode = M3D_ERR_ALLOC;
            return NULL;
        }
        goto gen;
    }
    if (actionid == M3D_UNDEF || !frameid) {
    gen:
        s = 0;
        for (i = 0; i < model->numbone; i++) {
            skeleton[i].boneid = i;
            skeleton[i].pos = model->bone[i].pos;
            skeleton[i].ori = model->bone[i].ori;
        }
    }
    if (actionid < model->numaction && (frameid || !model->action[actionid].frame[0].msec)) {
        for (; s <= frameid; s++) {
            fr = &model->action[actionid].frame[s];
            for (i = 0; i < fr->numtransform; i++) {
                skeleton[fr->transform[i].boneid].pos = fr->transform[i].pos;
                skeleton[fr->transform[i].boneid].ori = fr->transform[i].ori;
            }
        }
    }
    return skeleton;
}

#ifndef M3D_NOANIMATION
/**
 * Returns interpolated animation-pose, a working copy (should be freed after use)
 */
m3db_t *m3d_pose(m3d_t *model, M3D_INDEX actionid, uint32_t msec) {
    unsigned int i, j, l;
    M3D_FLOAT r[16], t, c, d, s;
    m3db_t *ret;
    m3dv_t *v, *p, *f;
    m3dtr_t *tmp;
    m3dfr_t *fr;

    if (!model || !model->numbone || !model->bone) {
        model->errcode = M3D_ERR_UNKFRAME;
        return NULL;
    }
    ret = (m3db_t *)M3D_MALLOC(model->numbone * sizeof(m3db_t));
    if (!ret) {
        model->errcode = M3D_ERR_ALLOC;
        return NULL;
    }
    memcpy(ret, model->bone, model->numbone * sizeof(m3db_t));
    for (i = 0; i < model->numbone; i++)
        _m3d_inv((M3D_FLOAT *)&ret[i].mat4);
    if (!model->action || actionid >= model->numaction) {
        model->errcode = M3D_ERR_UNKFRAME;
        return ret;
    }
    msec %= model->action[actionid].durationmsec;
    model->errcode = M3D_SUCCESS;
    fr = &model->action[actionid].frame[0];
    for (j = l = 0; j < model->action[actionid].numframe && model->action[actionid].frame[j].msec <= msec; j++) {
        fr = &model->action[actionid].frame[j];
        l = fr->msec;
        for (i = 0; i < fr->numtransform; i++) {
            ret[fr->transform[i].boneid].pos = fr->transform[i].pos;
            ret[fr->transform[i].boneid].ori = fr->transform[i].ori;
        }
    }
    if (l != msec) {
        model->vertex = (m3dv_t *)M3D_REALLOC(model->vertex, (model->numvertex + 2 * model->numbone) * sizeof(m3dv_t));
        if (!model->vertex) {
            free(ret);
            model->errcode = M3D_ERR_ALLOC;
            return NULL;
        }
        tmp = (m3dtr_t *)M3D_MALLOC(model->numbone * sizeof(m3dtr_t));
        if (tmp) {
            for (i = 0; i < model->numbone; i++) {
                tmp[i].pos = ret[i].pos;
                tmp[i].ori = ret[i].ori;
            }
            fr = &model->action[actionid].frame[j % model->action[actionid].numframe];
            t = l >= fr->msec ? (M3D_FLOAT)1.0 : (M3D_FLOAT)(msec - l) / (M3D_FLOAT)(fr->msec - l);
            for (i = 0; i < fr->numtransform; i++) {
                tmp[fr->transform[i].boneid].pos = fr->transform[i].pos;
                tmp[fr->transform[i].boneid].ori = fr->transform[i].ori;
            }
            for (i = 0, j = model->numvertex; i < model->numbone; i++) {
                /* interpolation of position */
                if (ret[i].pos != tmp[i].pos) {
                    p = &model->vertex[ret[i].pos];
                    f = &model->vertex[tmp[i].pos];
                    v = &model->vertex[j];
                    v->x = p->x + t * (f->x - p->x);
                    v->y = p->y + t * (f->y - p->y);
                    v->z = p->z + t * (f->z - p->z);
                    ret[i].pos = j++;
                }
                /* interpolation of orientation */
                if (ret[i].ori != tmp[i].ori) {
                    p = &model->vertex[ret[i].ori];
                    f = &model->vertex[tmp[i].ori];
                    v = &model->vertex[j];
                    d = p->w * f->w + p->x * f->x + p->y * f->y + p->z * f->z;
                    if (d < 0) {
                        d = -d;
                        s = (M3D_FLOAT)-1.0;
                    } else
                        s = (M3D_FLOAT)1.0;
#if 0
                    /* don't use SLERP, requires two more variables, libm linkage and it is slow (but nice) */
                    a = (M3D_FLOAT)1.0 - t; b = t;
                    if(d < (M3D_FLOAT)0.999999) { c = acosf(d); b = 1 / sinf(c); a = sinf(a * c) * b; b *= sinf(t * c) * s; }
                    v->x = p->x * a + f->x * b;
                    v->y = p->y * a + f->y * b;
                    v->z = p->z * a + f->z * b;
                    v->w = p->w * a + f->w * b;
#else
                    /* approximated NLERP, original approximation by Arseny Kapoulkine, heavily optimized by me */
                    c = t - (M3D_FLOAT)0.5;
                    t += t * c * (t - (M3D_FLOAT)1.0) * (((M3D_FLOAT)1.0904 + d * ((M3D_FLOAT)-3.2452 + d * ((M3D_FLOAT)3.55645 - d * (M3D_FLOAT)1.43519))) * c * c + ((M3D_FLOAT)0.848013 + d * ((M3D_FLOAT)-1.06021 + d * (M3D_FLOAT)0.215638)));
                    v->x = p->x + t * (s * f->x - p->x);
                    v->y = p->y + t * (s * f->y - p->y);
                    v->z = p->z + t * (s * f->z - p->z);
                    v->w = p->w + t * (s * f->w - p->w);
                    d = _m3d_rsq(v->w * v->w + v->x * v->x + v->y * v->y + v->z * v->z);
                    v->x *= d;
                    v->y *= d;
                    v->z *= d;
                    v->w *= d;
#endif
                    ret[i].ori = j++;
                }
            }
            M3D_FREE(tmp);
        }
    }
    for (i = 0; i < model->numbone; i++) {
        if (ret[i].parent == M3D_UNDEF) {
            _m3d_mat((M3D_FLOAT *)&ret[i].mat4, &model->vertex[ret[i].pos], &model->vertex[ret[i].ori]);
        } else {
            _m3d_mat((M3D_FLOAT *)&r, &model->vertex[ret[i].pos], &model->vertex[ret[i].ori]);
            _m3d_mul((M3D_FLOAT *)&ret[i].mat4, (M3D_FLOAT *)&ret[ret[i].parent].mat4, (M3D_FLOAT *)&r);
        }
    }
    return ret;
}

#endif /* M3D_NOANIMATION */

#endif /* M3D_IMPLEMENTATION */

#if !defined(M3D_NODUP) && (!defined(M3D_NOIMPORTER) || defined(M3D_EXPORTER))
/**
 * Free the in-memory model
 */
void m3d_free(m3d_t *model) {
    unsigned int i, j;

    if (!model) return;
#ifdef M3D_ASCII
    /* if model imported from ASCII, we have to free all strings as well */
    if (model->flags & M3D_FLG_FREESTR) {
        if (model->name) M3D_FREE(model->name);
        if (model->license) M3D_FREE(model->license);
        if (model->author) M3D_FREE(model->author);
        if (model->desc) M3D_FREE(model->desc);
        if (model->bone)
            for (i = 0; i < model->numbone; i++)
                if (model->bone[i].name)
                    M3D_FREE(model->bone[i].name);
        if (model->shape)
            for (i = 0; i < model->numshape; i++)
                if (model->shape[i].name)
                    M3D_FREE(model->shape[i].name);
        if (model->material)
            for (i = 0; i < model->nummaterial; i++)
                if (model->material[i].name)
                    M3D_FREE(model->material[i].name);
        if (model->action)
            for (i = 0; i < model->numaction; i++)
                if (model->action[i].name)
                    M3D_FREE(model->action[i].name);
        if (model->texture)
            for (i = 0; i < model->numtexture; i++)
                if (model->texture[i].name)
                    M3D_FREE(model->texture[i].name);
        if (model->inlined)
            for (i = 0; i < model->numinlined; i++) {
                if (model->inlined[i].name)
                    M3D_FREE(model->inlined[i].name);
                if (model->inlined[i].data)
                    M3D_FREE(model->inlined[i].data);
            }
        if (model->extra)
            for (i = 0; i < model->numextra; i++)
                if (model->extra[i])
                    M3D_FREE(model->extra[i]);
        if (model->label)
            for (i = 0; i < model->numlabel; i++) {
                if (model->label[i].name) {
                    for (j = i + 1; j < model->numlabel; j++)
                        if (model->label[j].name == model->label[i].name)
                            model->label[j].name = NULL;
                    M3D_FREE(model->label[i].name);
                }
                if (model->label[i].lang) {
                    for (j = i + 1; j < model->numlabel; j++)
                        if (model->label[j].lang == model->label[i].lang)
                            model->label[j].lang = NULL;
                    M3D_FREE(model->label[i].lang);
                }
                if (model->label[i].text)
                    M3D_FREE(model->label[i].text);
            }
        if (model->preview.data)
            M3D_FREE(model->preview.data);
    }
#endif
    if (model->flags & M3D_FLG_FREERAW) M3D_FREE(model->raw);

    if (model->tmap) M3D_FREE(model->tmap);
    if (model->bone) {
        for (i = 0; i < model->numbone; i++)
            if (model->bone[i].weight)
                M3D_FREE(model->bone[i].weight);
        M3D_FREE(model->bone);
    }
    if (model->skin) M3D_FREE(model->skin);
    if (model->vertex) M3D_FREE(model->vertex);
    if (model->face) M3D_FREE(model->face);
    if (model->shape) {
        for (i = 0; i < model->numshape; i++) {
            if (model->shape[i].cmd) {
                for (j = 0; j < model->shape[i].numcmd; j++)
                    if (model->shape[i].cmd[j].arg) M3D_FREE(model->shape[i].cmd[j].arg);
                M3D_FREE(model->shape[i].cmd);
            }
        }
        M3D_FREE(model->shape);
    }
    if (model->material && !(model->flags & M3D_FLG_MTLLIB)) {
        for (i = 0; i < model->nummaterial; i++)
            if (model->material[i].prop) M3D_FREE(model->material[i].prop);
        M3D_FREE(model->material);
    }
    if (model->texture) {
        for (i = 0; i < model->numtexture; i++)
            if (model->texture[i].d) M3D_FREE(model->texture[i].d);
        M3D_FREE(model->texture);
    }
    if (model->action) {
        for (i = 0; i < model->numaction; i++) {
            if (model->action[i].frame) {
                for (j = 0; j < model->action[i].numframe; j++)
                    if (model->action[i].frame[j].transform) M3D_FREE(model->action[i].frame[j].transform);
                M3D_FREE(model->action[i].frame);
            }
        }
        M3D_FREE(model->action);
    }
    if (model->label) M3D_FREE(model->label);
    if (model->inlined) M3D_FREE(model->inlined);
    if (model->extra) M3D_FREE(model->extra);
    free(model);
}
#endif

#ifdef M3D_EXPORTER
typedef struct {
    char *str;
    uint32_t offs;
} m3dstr_t;

typedef struct {
    m3dti_t data;
    M3D_INDEX oldidx;
    M3D_INDEX newidx;
} m3dtisave_t;

typedef struct {
    m3dv_t data;
    M3D_INDEX oldidx;
    M3D_INDEX newidx;
    unsigned char norm;
} m3dvsave_t;

typedef struct {
    m3ds_t data;
    M3D_INDEX oldidx;
    M3D_INDEX newidx;
} m3dssave_t;

typedef struct {
    m3df_t data;
    int group;
    uint8_t opacity;
} m3dfsave_t;

/* create unique list of strings */
static m3dstr_t *_m3d_addstr(m3dstr_t *str, uint32_t *numstr, char *s) {
    uint32_t i;
    if (!s || !*s) return str;
    if (str) {
        for (i = 0; i < *numstr; i++)
            if (str[i].str == s || !strcmp(str[i].str, s)) return str;
    }
    str = (m3dstr_t *)M3D_REALLOC(str, ((*numstr) + 1) * sizeof(m3dstr_t));
    str[*numstr].str = s;
    str[*numstr].offs = 0;
    (*numstr)++;
    return str;
}

/* add strings to header */
m3dhdr_t *_m3d_addhdr(m3dhdr_t *h, m3dstr_t *s) {
    int i;
    char *safe = _m3d_safestr(s->str, 0);
    i = (int)strlen(safe);
    h = (m3dhdr_t *)M3D_REALLOC(h, h->length + i + 1);
    if (!h) {
        M3D_FREE(safe);
        return NULL;
    }
    memcpy((uint8_t *)h + h->length, safe, i + 1);
    s->offs = h->length - 16;
    h->length += i + 1;
    M3D_FREE(safe);
    return h;
}

/* return offset of string */
static uint32_t _m3d_stridx(m3dstr_t *str, uint32_t numstr, char *s) {
    uint32_t i;
    char *safe;
    if (!s || !*s) return 0;
    if (str) {
        safe = _m3d_safestr(s, 0);
        if (!safe) return 0;
        if (!*safe) {
            free(safe);
            return 0;
        }
        for (i = 0; i < numstr; i++)
            if (!strcmp(str[i].str, s)) {
                free(safe);
                return str[i].offs;
            }
        free(safe);
    }
    return 0;
}

/* compare to faces by their material */
static int _m3d_facecmp(const void *a, const void *b) {
    const m3dfsave_t *A = (const m3dfsave_t *)a, *B = (const m3dfsave_t *)b;
    return A->group != B->group ? A->group - B->group : (A->opacity != B->opacity ? (int)B->opacity - (int)A->opacity : (int)A->data.materialid - (int)B->data.materialid);
}
/* compare face groups */
static int _m3d_grpcmp(const void *a, const void *b) {
    return *((uint32_t *)a) - *((uint32_t *)b);
}
/* compare UVs */
static int _m3d_ticmp(const void *a, const void *b) {
    return memcmp(a, b, sizeof(m3dti_t));
}
/* compare skin groups */
static int _m3d_skincmp(const void *a, const void *b) {
    return memcmp(a, b, sizeof(m3ds_t));
}
/* compare vertices */
static int _m3d_vrtxcmp(const void *a, const void *b) {
    int c = memcmp(a, b, 3 * sizeof(M3D_FLOAT));
    if (c) return c;
    c = ((m3dvsave_t *)a)->norm - ((m3dvsave_t *)b)->norm;
    if (c) return c;
    return memcmp(a, b, sizeof(m3dv_t));
}
/* compare labels */
static _inline int _m3d_strcmp(char *a, char *b) {
    if (a == NULL && b != NULL) return -1;
    if (a != NULL && b == NULL) return 1;
    if (a == NULL && b == NULL) return 0;
    return strcmp(a, b);
}
static int _m3d_lblcmp(const void *a, const void *b) {
    const m3dl_t *A = (const m3dl_t *)a, *B = (const m3dl_t *)b;
    int c = _m3d_strcmp(A->lang, B->lang);
    if (!c) c = _m3d_strcmp(A->name, B->name);
    if (!c) c = _m3d_strcmp(A->text, B->text);
    return c;
}
/* compare two colors by HSV value */
_inline static int _m3d_cmapcmp(const void *a, const void *b) {
    uint8_t *A = (uint8_t *)a, *B = (uint8_t *)b;
    _register int m, vA, vB;
    /* get HSV value for A */
    m = A[2] < A[1] ? A[2] : A[1];
    if (A[0] < m) m = A[0];
    vA = A[2] > A[1] ? A[2] : A[1];
    if (A[0] > vA) vA = A[0];
    /* get HSV value for B */
    m = B[2] < B[1] ? B[2] : B[1];
    if (B[0] < m) m = B[0];
    vB = B[2] > B[1] ? B[2] : B[1];
    if (B[0] > vB) vB = B[0];
    return vA - vB;
}

/* create sorted list of colors */
static uint32_t *_m3d_addcmap(uint32_t *cmap, uint32_t *numcmap, uint32_t color) {
    uint32_t i;
    if (cmap) {
        for (i = 0; i < *numcmap; i++)
            if (cmap[i] == color) return cmap;
    }
    cmap = (uint32_t *)M3D_REALLOC(cmap, ((*numcmap) + 1) * sizeof(uint32_t));
    for (i = 0; i < *numcmap && _m3d_cmapcmp(&color, &cmap[i]) > 0; i++)
        ;
    if (i < *numcmap) memmove(&cmap[i + 1], &cmap[i], ((*numcmap) - i) * sizeof(uint32_t));
    cmap[i] = color;
    (*numcmap)++;
    return cmap;
}

/* look up a color and return its index */
static uint32_t _m3d_cmapidx(uint32_t *cmap, uint32_t numcmap, uint32_t color) {
    uint32_t i;
    if (numcmap >= 65536)
        return color;
    for (i = 0; i < numcmap; i++)
        if (cmap[i] == color) return i;
    return 0;
}

/* add index to output */
static unsigned char *_m3d_addidx(unsigned char *out, char type, uint32_t idx) {
    switch (type) {
        case 1: *out++ = (uint8_t)(idx); break;
        case 2:
            *((uint16_t *)out) = (uint16_t)(idx);
            out += 2;
            break;
        case 4:
            *((uint32_t *)out) = (uint32_t)(idx);
            out += 4;
            break;
            /* case 0: case 8: break; */
    }
    return out;
}

/* round a vertex position */
static void _m3d_round(int quality, m3dv_t *src, m3dv_t *dst) {
    _register int t;
    /* copy additional attributes */
    if (src != dst) memcpy(dst, src, sizeof(m3dv_t));
    /* round according to quality */
    switch (quality) {
        case M3D_EXP_INT8:
            t = (int)(src->x * 127 + (src->x >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->x = (M3D_FLOAT)t / (M3D_FLOAT)127.0;
            t = (int)(src->y * 127 + (src->y >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->y = (M3D_FLOAT)t / (M3D_FLOAT)127.0;
            t = (int)(src->z * 127 + (src->z >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->z = (M3D_FLOAT)t / (M3D_FLOAT)127.0;
            t = (int)(src->w * 127 + (src->w >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->w = (M3D_FLOAT)t / (M3D_FLOAT)127.0;
            break;
        case M3D_EXP_INT16:
            t = (int)(src->x * 32767 + (src->x >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->x = (M3D_FLOAT)t / (M3D_FLOAT)32767.0;
            t = (int)(src->y * 32767 + (src->y >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->y = (M3D_FLOAT)t / (M3D_FLOAT)32767.0;
            t = (int)(src->z * 32767 + (src->z >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->z = (M3D_FLOAT)t / (M3D_FLOAT)32767.0;
            t = (int)(src->w * 32767 + (src->w >= 0 ? (M3D_FLOAT)0.5 : (M3D_FLOAT)-0.5));
            dst->w = (M3D_FLOAT)t / (M3D_FLOAT)32767.0;
            break;
    }
    if (dst->x == (M3D_FLOAT)-0.0) dst->x = (M3D_FLOAT)0.0;
    if (dst->y == (M3D_FLOAT)-0.0) dst->y = (M3D_FLOAT)0.0;
    if (dst->z == (M3D_FLOAT)-0.0) dst->z = (M3D_FLOAT)0.0;
    if (dst->w == (M3D_FLOAT)-0.0) dst->w = (M3D_FLOAT)0.0;
}

#ifdef M3D_ASCII
/* add a bone to ascii output */
static char *_m3d_prtbone(char *ptr, m3db_t *bone, M3D_INDEX numbone, M3D_INDEX parent, uint32_t level, M3D_INDEX *vrtxidx) {
    uint32_t i, j;
    char *sn;

    if (level > M3D_BONEMAXLEVEL || !bone) return ptr;
    for (i = 0; i < numbone; i++) {
        if (bone[i].parent == parent) {
            for (j = 0; j < level; j++)
                *ptr++ = '/';
            sn = _m3d_safestr(bone[i].name, 0);
            ptr += sprintf(ptr, "%d %d %s\r\n", vrtxidx[bone[i].pos], vrtxidx[bone[i].ori], sn);
            M3D_FREE(sn);
            ptr = _m3d_prtbone(ptr, bone, numbone, i, level + 1, vrtxidx);
        }
    }
    return ptr;
}
#endif

/**
 * Function to encode an in-memory model into on storage Model 3D format
 */
unsigned char *m3d_save(m3d_t *model, int quality, int flags, unsigned int *size) {
#ifdef M3D_ASCII
    const char *ol;
    char *ptr;
#endif
    char vc_s, vi_s, si_s, ci_s, ti_s, bi_s, nb_s, sk_s, fc_s, hi_s, fi_s;
    char *sn = NULL, *sl = NULL, *sa = NULL, *sd = NULL;
    unsigned char *out = NULL, *z = NULL, weights[M3D_NUMBONE], *norm = NULL;
    unsigned int i, j, k, l, n, len, chunklen, *length;
    M3D_FLOAT scale = (M3D_FLOAT)0.0, min_x, max_x, min_y, max_y, min_z, max_z;
    M3D_INDEX last, *vrtxidx = NULL, *mtrlidx = NULL, *tmapidx = NULL, *skinidx = NULL;
    uint32_t idx, numcmap = 0, *cmap = NULL, numvrtx = 0, maxvrtx = 0, numtmap = 0, maxtmap = 0, numproc = 0;
    uint32_t numskin = 0, maxskin = 0, numstr = 0, maxt = 0, maxbone = 0, numgrp = 0, maxgrp = 0, *grpidx = NULL;
    uint8_t *opa = nullptr;
    m3dcd_t *cd;
    m3dc_t *cmd;
    m3dstr_t *str = NULL;
    m3dvsave_t *vrtx = NULL, vertex;
    m3dtisave_t *tmap = NULL, tcoord;
    m3dssave_t *skin = NULL, sk;
    m3dfsave_t *face = NULL;
    m3dhdr_t *h = NULL;
    m3dm_t *m;
    m3da_t *a;

    if (!model) {
        if (size) *size = 0;
        return NULL;
    }
    model->errcode = M3D_SUCCESS;
#ifdef M3D_ASCII
    if (flags & M3D_EXP_ASCII) quality = M3D_EXP_DOUBLE;
#endif
    vrtxidx = (M3D_INDEX *)M3D_MALLOC(model->numvertex * sizeof(M3D_INDEX));
    if (!vrtxidx) goto memerr;
    memset(vrtxidx, 255, model->numvertex * sizeof(M3D_INDEX));
    if (model->numvertex && !(flags & M3D_EXP_NONORMAL)) {
        norm = (unsigned char *)M3D_MALLOC(model->numvertex * sizeof(unsigned char));
        if (!norm) goto memerr;
        memset(norm, 0, model->numvertex * sizeof(unsigned char));
    }
    if (model->nummaterial && !(flags & M3D_EXP_NOMATERIAL)) {
        mtrlidx = (M3D_INDEX *)M3D_MALLOC(model->nummaterial * sizeof(M3D_INDEX));
        if (!mtrlidx) goto memerr;
        memset(mtrlidx, 255, model->nummaterial * sizeof(M3D_INDEX));
        opa = (uint8_t *)M3D_MALLOC(model->nummaterial * 2 * sizeof(M3D_INDEX));
        if (!opa) goto memerr;
        memset(opa, 255, model->nummaterial * 2 * sizeof(M3D_INDEX));
    }
    if (model->numtmap && !(flags & M3D_EXP_NOTXTCRD)) {
        tmapidx = (M3D_INDEX *)M3D_MALLOC(model->numtmap * sizeof(M3D_INDEX));
        if (!tmapidx) goto memerr;
        memset(tmapidx, 255, model->numtmap * sizeof(M3D_INDEX));
    }
    /** collect array elements that are actually referenced **/
    if (!(flags & M3D_EXP_NOFACE)) {
        /* face */
        if (model->numface && model->face) {
            M3D_LOG("Processing mesh face");
            face = (m3dfsave_t *)M3D_MALLOC(model->numface * sizeof(m3dfsave_t));
            if (!face) goto memerr;
            for (i = 0; i < model->numface; i++) {
                memcpy(&face[i].data, &model->face[i], sizeof(m3df_t));
                face[i].group = 0;
                face[i].opacity = 255;
                if (!(flags & M3D_EXP_NOMATERIAL) && model->face[i].materialid < model->nummaterial) {
                    if (model->material[model->face[i].materialid].numprop) {
                        mtrlidx[model->face[i].materialid] = 0;
                        if (opa[model->face[i].materialid * 2]) {
                            m = &model->material[model->face[i].materialid];
                            for (j = 0; j < m->numprop; j++)
                                if (m->prop[j].type == m3dp_Kd) {
                                    opa[model->face[i].materialid * 2 + 1] = ((uint8_t *)&m->prop[j].value.color)[3];
                                    break;
                                }
                            for (j = 0; j < m->numprop; j++)
                                if (m->prop[j].type == m3dp_d) {
                                    opa[model->face[i].materialid * 2 + 1] = (uint8_t)(m->prop[j].value.fnum * 255);
                                    break;
                                }
                            opa[model->face[i].materialid * 2] = 0;
                        }
                        face[i].opacity = opa[model->face[i].materialid * 2 + 1];
                    } else
                        face[i].data.materialid = M3D_UNDEF;
                }
                for (j = 0; j < 3; j++) {
                    k = model->face[i].vertex[j];
                    if (k < model->numvertex)
                        vrtxidx[k] = 0;
                    if (!(flags & M3D_EXP_NOCMAP)) {
                        cmap = _m3d_addcmap(cmap, &numcmap, model->vertex[k].color);
                        if (!cmap) goto memerr;
                    }
                    k = model->face[i].normal[j];
                    if (k < model->numvertex && !(flags & M3D_EXP_NONORMAL)) {
                        vrtxidx[k] = 0;
                        norm[k] = 1;
                    }
                    k = model->face[i].texcoord[j];
                    if (k < model->numtmap && !(flags & M3D_EXP_NOTXTCRD))
                        tmapidx[k] = 0;
                }
                /* convert from CW to CCW */
                if (flags & M3D_EXP_IDOSUCK) {
                    j = face[i].data.vertex[1];
                    face[i].data.vertex[1] = face[i].data.vertex[2];
                    face[i].data.vertex[2] = face[i].data.vertex[1];
                    j = face[i].data.normal[1];
                    face[i].data.normal[1] = face[i].data.normal[2];
                    face[i].data.normal[2] = face[i].data.normal[1];
                    j = face[i].data.texcoord[1];
                    face[i].data.texcoord[1] = face[i].data.texcoord[2];
                    face[i].data.texcoord[2] = face[i].data.texcoord[1];
                }
            }
        }
        if (model->numshape && model->shape) {
            M3D_LOG("Processing shape face");
            for (i = 0; i < model->numshape; i++) {
                if (!model->shape[i].numcmd) continue;
                str = _m3d_addstr(str, &numstr, model->shape[i].name);
                if (!str) goto memerr;
                for (j = 0; j < model->shape[i].numcmd; j++) {
                    cmd = &model->shape[i].cmd[j];
                    if (cmd->type >= (unsigned int)(sizeof(m3d_commandtypes) / sizeof(m3d_commandtypes[0])) || !cmd->arg)
                        continue;
                    if (cmd->type == m3dc_mesh) {
                        if (numgrp + 2 < maxgrp) {
                            maxgrp += 1024;
                            grpidx = (uint32_t *)realloc(grpidx, maxgrp * sizeof(uint32_t));
                            if (!grpidx) goto memerr;
                            if (!numgrp) {
                                grpidx[0] = 0;
                                grpidx[1] = model->numface;
                                numgrp += 2;
                            }
                        }
                        grpidx[numgrp + 0] = cmd->arg[0];
                        grpidx[numgrp + 1] = cmd->arg[0] + cmd->arg[1];
                        numgrp += 2;
                    }
                    cd = &m3d_commandtypes[cmd->type];
                    for (k = n = 0, l = cd->p; k < l; k++)
                        switch (cd->a[((k - n) % (cd->p - n)) + n]) {
                            case m3dcp_mi_t:
                                if (!(flags & M3D_EXP_NOMATERIAL) && cmd->arg[k] < model->nummaterial)
                                    mtrlidx[cmd->arg[k]] = 0;
                                break;
                            case m3dcp_ti_t:
                                if (!(flags & M3D_EXP_NOTXTCRD) && cmd->arg[k] < model->numtmap)
                                    tmapidx[cmd->arg[k]] = 0;
                                break;
                            case m3dcp_qi_t:
                            case m3dcp_vi_t:
                                if (cmd->arg[k] < model->numvertex)
                                    vrtxidx[cmd->arg[k]] = 0;
                                break;
                            case m3dcp_va_t:
                                n = k + 1;
                                l += (cmd->arg[k] - 1) * (cd->p - k - 1);
                                break;
                        }
                }
            }
        }
        if (model->numface && face) {
            if (numgrp && grpidx) {
                qsort(grpidx, numgrp, sizeof(uint32_t), _m3d_grpcmp);
                for (i = j = 0; i < model->numface && j < numgrp; i++) {
                    while (j < numgrp && grpidx[j] < i)
                        j++;
                    face[i].group = j;
                }
            }
            qsort(face, model->numface, sizeof(m3dfsave_t), _m3d_facecmp);
        }
        if (grpidx) {
            M3D_FREE(grpidx);
            grpidx = NULL;
        }
        if (model->numlabel && model->label) {
            M3D_LOG("Processing annotation labels");
            for (i = 0; i < model->numlabel; i++) {
                str = _m3d_addstr(str, &numstr, model->label[i].name);
                str = _m3d_addstr(str, &numstr, model->label[i].lang);
                str = _m3d_addstr(str, &numstr, model->label[i].text);
                if (!(flags & M3D_EXP_NOCMAP)) {
                    cmap = _m3d_addcmap(cmap, &numcmap, model->label[i].color);
                    if (!cmap) goto memerr;
                }
                if (model->label[i].vertexid < model->numvertex)
                    vrtxidx[model->label[i].vertexid] = 0;
            }
            qsort(model->label, model->numlabel, sizeof(m3dl_t), _m3d_lblcmp);
        }
    } else if (!(flags & M3D_EXP_NOMATERIAL)) {
        /* without a face, simply add all materials, because it can be an mtllib */
        for (i = 0; i < model->nummaterial; i++)
            mtrlidx[i] = i;
    }
    /* bind-pose skeleton */
    if (model->numbone && model->bone && !(flags & M3D_EXP_NOBONE)) {
        M3D_LOG("Processing bones");
        for (i = 0; i < model->numbone; i++) {
            str = _m3d_addstr(str, &numstr, model->bone[i].name);
            if (!str) goto memerr;
            k = model->bone[i].pos;
            if (k < model->numvertex)
                vrtxidx[k] = 0;
            k = model->bone[i].ori;
            if (k < model->numvertex)
                vrtxidx[k] = 0;
        }
    }
    /* actions, animated skeleton poses */
    if (model->numaction && model->action && !(flags & M3D_EXP_NOACTION)) {
        M3D_LOG("Processing action list");
        for (j = 0; j < model->numaction; j++) {
            a = &model->action[j];
            str = _m3d_addstr(str, &numstr, a->name);
            if (!str) goto memerr;
            if (a->numframe > 65535) a->numframe = 65535;
            for (i = 0; i < a->numframe; i++) {
                for (l = 0; l < a->frame[i].numtransform; l++) {
                    k = a->frame[i].transform[l].pos;
                    if (k < model->numvertex)
                        vrtxidx[k] = 0;
                    k = a->frame[i].transform[l].ori;
                    if (k < model->numvertex)
                        vrtxidx[k] = 0;
                }
                if (l > maxt) maxt = l;
            }
        }
    }
    /* add colors to color map and texture names to string table */
    if (!(flags & M3D_EXP_NOMATERIAL)) {
        M3D_LOG("Processing materials");
        for (i = k = 0; i < model->nummaterial; i++) {
            if (mtrlidx[i] == M3D_UNDEF || !model->material[i].numprop) continue;
            mtrlidx[i] = k++;
            m = &model->material[i];
            str = _m3d_addstr(str, &numstr, m->name);
            if (!str) goto memerr;
            if (m->prop)
                for (j = 0; j < m->numprop; j++) {
                    if (!(flags & M3D_EXP_NOCMAP) && m->prop[j].type < 128) {
                        for (l = 0; l < sizeof(m3d_propertytypes) / sizeof(m3d_propertytypes[0]); l++) {
                            if (m->prop[j].type == m3d_propertytypes[l].id && m3d_propertytypes[l].format == m3dpf_color) {
                                ((uint8_t *)&m->prop[j].value.color)[3] = opa[i * 2 + 1];
                                cmap = _m3d_addcmap(cmap, &numcmap, m->prop[j].value.color);
                                if (!cmap) goto memerr;
                                break;
                            }
                        }
                    }
                    if (m->prop[j].type >= 128 && m->prop[j].value.textureid < model->numtexture &&
                            model->texture[m->prop[j].value.textureid].name) {
                        str = _m3d_addstr(str, &numstr, model->texture[m->prop[j].value.textureid].name);
                        if (!str) goto memerr;
                    }
                }
        }
    }
    /* if there's only one black color, don't store it */
    if (numcmap == 1 && cmap && !cmap[0]) numcmap = 0;

    /** compress lists **/
    if (model->numtmap && !(flags & M3D_EXP_NOTXTCRD)) {
        M3D_LOG("Compressing tmap");
        tmap = (m3dtisave_t *)M3D_MALLOC(model->numtmap * sizeof(m3dtisave_t));
        if (!tmap) goto memerr;
        for (i = 0; i < model->numtmap; i++) {
            if (tmapidx[i] == M3D_UNDEF) continue;
            switch (quality) {
                case M3D_EXP_INT8:
                    l = (unsigned int)(model->tmap[i].u * 255);
                    tcoord.data.u = (M3D_FLOAT)l / (M3D_FLOAT)255.0;
                    l = (unsigned int)(model->tmap[i].v * 255);
                    tcoord.data.v = (M3D_FLOAT)l / (M3D_FLOAT)255.0;
                    break;
                case M3D_EXP_INT16:
                    l = (unsigned int)(model->tmap[i].u * 65535);
                    tcoord.data.u = (M3D_FLOAT)l / (M3D_FLOAT)65535.0;
                    l = (unsigned int)(model->tmap[i].v * 65535);
                    tcoord.data.v = (M3D_FLOAT)l / (M3D_FLOAT)65535.0;
                    break;
                default:
                    tcoord.data.u = model->tmap[i].u;
                    tcoord.data.v = model->tmap[i].v;
                    break;
            }
            if (flags & M3D_EXP_FLIPTXTCRD)
                tcoord.data.v = (M3D_FLOAT)1.0 - tcoord.data.v;
            tcoord.oldidx = i;
            memcpy(&tmap[numtmap++], &tcoord, sizeof(m3dtisave_t));
        }
        if (numtmap) {
            qsort(tmap, numtmap, sizeof(m3dtisave_t), _m3d_ticmp);
            memcpy(&tcoord.data, &tmap[0], sizeof(m3dti_t));
            for (i = 0; i < numtmap; i++) {
                if (memcmp(&tcoord.data, &tmap[i].data, sizeof(m3dti_t))) {
                    memcpy(&tcoord.data, &tmap[i].data, sizeof(m3dti_t));
                    maxtmap++;
                }
                tmap[i].newidx = maxtmap;
                tmapidx[tmap[i].oldidx] = maxtmap;
            }
            maxtmap++;
        }
    }
    if (model->numskin && model->skin && !(flags & M3D_EXP_NOBONE)) {
        M3D_LOG("Compressing skin");
        skinidx = (M3D_INDEX *)M3D_MALLOC(model->numskin * sizeof(M3D_INDEX));
        if (!skinidx) goto memerr;
        skin = (m3dssave_t *)M3D_MALLOC(model->numskin * sizeof(m3dssave_t));
        if (!skin) goto memerr;
        memset(skinidx, 255, model->numskin * sizeof(M3D_INDEX));
        for (i = 0; i < model->numvertex; i++) {
            if (vrtxidx[i] != M3D_UNDEF && model->vertex[i].skinid < model->numskin)
                skinidx[model->vertex[i].skinid] = 0;
        }
        for (i = 0; i < model->numskin; i++) {
            if (skinidx[i] == M3D_UNDEF) continue;
            memset(&sk, 0, sizeof(m3dssave_t));
            for (j = 0, min_x = (M3D_FLOAT)0.0; j < M3D_NUMBONE && model->skin[i].boneid[j] != M3D_UNDEF &&
                                                model->skin[i].weight[j] > (M3D_FLOAT)0.0;
                    j++) {
                sk.data.boneid[j] = model->skin[i].boneid[j];
                sk.data.weight[j] = model->skin[i].weight[j];
                min_x += sk.data.weight[j];
            }
            if (j > maxbone) maxbone = j;
            if (min_x != (M3D_FLOAT)1.0 && min_x != (M3D_FLOAT)0.0)
                for (j = 0; j < M3D_NUMBONE && sk.data.weight[j] > (M3D_FLOAT)0.0; j++)
                    sk.data.weight[j] /= min_x;
            sk.oldidx = i;
            memcpy(&skin[numskin++], &sk, sizeof(m3dssave_t));
        }
        if (numskin) {
            qsort(skin, numskin, sizeof(m3dssave_t), _m3d_skincmp);
            memcpy(&sk.data, &skin[0].data, sizeof(m3ds_t));
            for (i = 0; i < numskin; i++) {
                if (memcmp(&sk.data, &skin[i].data, sizeof(m3ds_t))) {
                    memcpy(&sk.data, &skin[i].data, sizeof(m3ds_t));
                    maxskin++;
                }
                skin[i].newidx = maxskin;
                skinidx[skin[i].oldidx] = maxskin;
            }
            maxskin++;
        }
    }

    M3D_LOG("Compressing vertex list");
    min_x = min_y = min_z = (M3D_FLOAT)1e10;
    max_x = max_y = max_z = (M3D_FLOAT)-1e10;
    if (vrtxidx) {
        vrtx = (m3dvsave_t *)M3D_MALLOC(model->numvertex * sizeof(m3dvsave_t));
        if (!vrtx) goto memerr;
        for (i = numvrtx = 0; i < model->numvertex; i++) {
            if (vrtxidx[i] == M3D_UNDEF) continue;
            _m3d_round(quality, &model->vertex[i], &vertex.data);
            vertex.norm = norm ? norm[i] : 0;
            if (vertex.data.skinid != M3D_INDEXMAX && !vertex.norm) {
                vertex.data.skinid = vertex.data.skinid != M3D_UNDEF && skinidx ? skinidx[vertex.data.skinid] : M3D_UNDEF;
                if (vertex.data.x > max_x) max_x = vertex.data.x;
                if (vertex.data.x < min_x) min_x = vertex.data.x;
                if (vertex.data.y > max_y) max_y = vertex.data.y;
                if (vertex.data.y < min_y) min_y = vertex.data.y;
                if (vertex.data.z > max_z) max_z = vertex.data.z;
                if (vertex.data.z < min_z) min_z = vertex.data.z;
            }
#ifdef M3D_VERTEXTYPE
            vertex.data.type = 0;
#endif
            vertex.oldidx = i;
            memcpy(&vrtx[numvrtx++], &vertex, sizeof(m3dvsave_t));
        }
        if (numvrtx) {
            qsort(vrtx, numvrtx, sizeof(m3dvsave_t), _m3d_vrtxcmp);
            memcpy(&vertex.data, &vrtx[0].data, sizeof(m3dv_t));
            for (i = 0; i < numvrtx; i++) {
                if (memcmp(&vertex.data, &vrtx[i].data, vrtx[i].norm ? 3 * sizeof(M3D_FLOAT) : sizeof(m3dv_t))) {
                    memcpy(&vertex.data, &vrtx[i].data, sizeof(m3dv_t));
                    maxvrtx++;
                }
                vrtx[i].newidx = maxvrtx;
                vrtxidx[vrtx[i].oldidx] = maxvrtx;
            }
            maxvrtx++;
        }
    }
    if (skinidx) {
        M3D_FREE(skinidx);
        skinidx = NULL;
    }
    if (norm) {
        M3D_FREE(norm);
        norm = NULL;
    }

    /* normalize to bounding cube */
    if (numvrtx && !(flags & M3D_EXP_NORECALC)) {
        M3D_LOG("Normalizing coordinates");
        if (min_x < (M3D_FLOAT)0.0) min_x = -min_x;
        if (max_x < (M3D_FLOAT)0.0) max_x = -max_x;
        if (min_y < (M3D_FLOAT)0.0) min_y = -min_y;
        if (max_y < (M3D_FLOAT)0.0) max_y = -max_y;
        if (min_z < (M3D_FLOAT)0.0) min_z = -min_z;
        if (max_z < (M3D_FLOAT)0.0) max_z = -max_z;
        scale = min_x;
        if (max_x > scale) scale = max_x;
        if (min_y > scale) scale = min_y;
        if (max_y > scale) scale = max_y;
        if (min_z > scale) scale = min_z;
        if (max_z > scale) scale = max_z;
        if (scale == (M3D_FLOAT)0.0) scale = (M3D_FLOAT)1.0;
        if (scale != (M3D_FLOAT)1.0) {
            for (i = 0; i < numvrtx; i++) {
                if (vrtx[i].data.skinid == M3D_INDEXMAX) continue;
                vrtx[i].data.x /= scale;
                vrtx[i].data.y /= scale;
                vrtx[i].data.z /= scale;
            }
        }
    }
    if (model->scale > (M3D_FLOAT)0.0) scale = model->scale;
    if (scale <= (M3D_FLOAT)0.0) scale = (M3D_FLOAT)1.0;

    /* meta info */
    sn = _m3d_safestr(model->name && *model->name ? model->name : (char *)"(noname)", 2);
    sl = _m3d_safestr(model->license ? model->license : (char *)"MIT", 2);
    sa = _m3d_safestr(model->author ? model->author : getenv("LOGNAME"), 2);
    if (!sn || !sl || !sa) {
    memerr:
        if (vrtxidx) M3D_FREE(vrtxidx);
        if (mtrlidx) M3D_FREE(mtrlidx);
        if (tmapidx) M3D_FREE(tmapidx);
        if (skinidx) M3D_FREE(skinidx);
        if (grpidx) M3D_FREE(grpidx);
        if (norm) M3D_FREE(norm);
        if (face) M3D_FREE(face);
        if (cmap) M3D_FREE(cmap);
        if (tmap) M3D_FREE(tmap);
        if (skin) M3D_FREE(skin);
        if (str) M3D_FREE(str);
        if (vrtx) M3D_FREE(vrtx);
        if (sn) M3D_FREE(sn);
        if (sl) M3D_FREE(sl);
        if (sa) M3D_FREE(sa);
        if (sd) M3D_FREE(sd);
        if (out) M3D_FREE(out);
        if (h) M3D_FREE(h);
        M3D_LOG("Out of memory");
        model->errcode = M3D_ERR_ALLOC;
        return NULL;
    }

    M3D_LOG("Serializing model");
#ifdef M3D_ASCII
    if (flags & M3D_EXP_ASCII) {
        /* use CRLF to make model creators on Win happy... */
        sd = _m3d_safestr(model->desc, 1);
        if (!sd) goto memerr;
        ol = setlocale(LC_NUMERIC, NULL);
        setlocale(LC_NUMERIC, "C");
        /* header */
        len = 64 + (unsigned int)(strlen(sn) + strlen(sl) + strlen(sa) + strlen(sd));
        out = (unsigned char *)M3D_MALLOC(len);
        if (!out) {
            setlocale(LC_NUMERIC, ol);
            goto memerr;
        }
        ptr = (char *)out;
        ptr += sprintf(ptr, "3dmodel %g\r\n%s\r\n%s\r\n%s\r\n%s\r\n\r\n", scale,
                sn, sl, sa, sd);
        M3D_FREE(sl);
        M3D_FREE(sa);
        M3D_FREE(sd);
        sl = sa = sd = NULL;
        /* preview chunk */
        if (model->preview.data && model->preview.length) {
            sl = _m3d_safestr(sn, 0);
            if (sl) {
                ptr -= (uintptr_t)out;
                len = (unsigned int)((uintptr_t)ptr + (uintptr_t)20);
                out = (unsigned char *)M3D_REALLOC(out, len);
                ptr += (uintptr_t)out;
                if (!out) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr += sprintf(ptr, "Preview\r\n%s.png\r\n\r\n", sl);
                M3D_FREE(sl);
                sl = NULL;
            }
        }
        M3D_FREE(sn);
        sn = NULL;
        /* texture map */
        if (numtmap && tmap && !(flags & M3D_EXP_NOTXTCRD) && !(flags & M3D_EXP_NOFACE)) {
            ptr -= (uintptr_t)out;
            len = (unsigned int)((uintptr_t)ptr + (uintptr_t)(maxtmap * 32) + (uintptr_t)12);
            out = (unsigned char *)M3D_REALLOC(out, len);
            ptr += (uintptr_t)out;
            if (!out) {
                setlocale(LC_NUMERIC, ol);
                goto memerr;
            }
            ptr += sprintf(ptr, "Textmap\r\n");
            last = M3D_UNDEF;
            for (i = 0; i < numtmap; i++) {
                if (tmap[i].newidx == last) continue;
                last = tmap[i].newidx;
                ptr += sprintf(ptr, "%g %g\r\n", tmap[i].data.u, tmap[i].data.v);
            }
            ptr += sprintf(ptr, "\r\n");
        }
        /* vertex chunk */
        if (numvrtx && vrtx && !(flags & M3D_EXP_NOFACE)) {
            ptr -= (uintptr_t)out;
            len = (unsigned int)((uintptr_t)ptr + (uintptr_t)(maxvrtx * 128) + (uintptr_t)10);
            out = (unsigned char *)M3D_REALLOC(out, len);
            ptr += (uintptr_t)out;
            if (!out) {
                setlocale(LC_NUMERIC, ol);
                goto memerr;
            }
            ptr += sprintf(ptr, "Vertex\r\n");
            last = M3D_UNDEF;
            for (i = 0; i < numvrtx; i++) {
                if (vrtx[i].newidx == last) continue;
                last = vrtx[i].newidx;
                ptr += sprintf(ptr, "%g %g %g %g", vrtx[i].data.x, vrtx[i].data.y, vrtx[i].data.z, vrtx[i].data.w);
                if (!(flags & M3D_EXP_NOCMAP) && vrtx[i].data.color)
                    ptr += sprintf(ptr, " #%08x", vrtx[i].data.color);
                if (!(flags & M3D_EXP_NOBONE) && model->numbone && maxskin && vrtx[i].data.skinid < M3D_INDEXMAX) {
                    if (skin[vrtx[i].data.skinid].data.weight[0] == (M3D_FLOAT)1.0)
                        ptr += sprintf(ptr, " %d", skin[vrtx[i].data.skinid].data.boneid[0]);
                    else
                        for (j = 0; j < M3D_NUMBONE && skin[vrtx[i].data.skinid].data.boneid[j] != M3D_UNDEF &&
                                    skin[vrtx[i].data.skinid].data.weight[j] > (M3D_FLOAT)0.0;
                                j++)
                            ptr += sprintf(ptr, " %d:%g", skin[vrtx[i].data.skinid].data.boneid[j],
                                    skin[vrtx[i].data.skinid].data.weight[j]);
                }
                ptr += sprintf(ptr, "\r\n");
            }
            ptr += sprintf(ptr, "\r\n");
        }
        /* bones chunk */
        if (model->numbone && model->bone && !(flags & M3D_EXP_NOBONE)) {
            ptr -= (uintptr_t)out;
            len = (unsigned int)((uintptr_t)ptr + (uintptr_t)9);
            for (i = 0; i < model->numbone; i++) {
                len += (unsigned int)strlen(model->bone[i].name) + 128;
            }
            out = (unsigned char *)M3D_REALLOC(out, len);
            ptr += (uintptr_t)out;
            if (!out) {
                setlocale(LC_NUMERIC, ol);
                goto memerr;
            }
            ptr += sprintf(ptr, "Bones\r\n");
            ptr = _m3d_prtbone(ptr, model->bone, model->numbone, M3D_UNDEF, 0, vrtxidx);
            ptr += sprintf(ptr, "\r\n");
        }
        /* materials */
        if (model->nummaterial && !(flags & M3D_EXP_NOMATERIAL)) {
            for (j = 0; j < model->nummaterial; j++) {
                if (mtrlidx[j] == M3D_UNDEF || !model->material[j].numprop || !model->material[j].prop) continue;
                m = &model->material[j];
                sn = _m3d_safestr(m->name, 0);
                if (!sn) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr -= (uintptr_t)out;
                len = (unsigned int)((uintptr_t)ptr + (uintptr_t)strlen(sn) + (uintptr_t)12);
                for (i = 0; i < m->numprop; i++) {
                    if (m->prop[i].type < 128)
                        len += 32;
                    else if (m->prop[i].value.textureid < model->numtexture && model->texture[m->prop[i].value.textureid].name)
                        len += (unsigned int)strlen(model->texture[m->prop[i].value.textureid].name) + 16;
                }
                out = (unsigned char *)M3D_REALLOC(out, len);
                ptr += (uintptr_t)out;
                if (!out) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr += sprintf(ptr, "Material %s\r\n", sn);
                M3D_FREE(sn);
                sn = NULL;
                for (i = 0; i < m->numprop; i++) {
                    k = 256;
                    if (m->prop[i].type >= 128) {
                        for (l = 0; l < sizeof(m3d_propertytypes) / sizeof(m3d_propertytypes[0]); l++)
                            if (m->prop[i].type == m3d_propertytypes[l].id) {
                                sn = m3d_propertytypes[l].key;
                                break;
                            }
                        if (!sn)
                            for (l = 0; l < sizeof(m3d_propertytypes) / sizeof(m3d_propertytypes[0]); l++)
                                if (m->prop[i].type - 128 == m3d_propertytypes[l].id) {
                                    sn = m3d_propertytypes[l].key;
                                    break;
                                }
                        k = sn ? m3dpf_map : 256;
                    } else {
                        for (l = 0; l < sizeof(m3d_propertytypes) / sizeof(m3d_propertytypes[0]); l++)
                            if (m->prop[i].type == m3d_propertytypes[l].id) {
                                sn = m3d_propertytypes[l].key;
                                k = m3d_propertytypes[l].format;
                                break;
                            }
                    }
                    switch (k) {
                        case m3dpf_color: ptr += sprintf(ptr, "%s #%08x\r\n", sn, m->prop[i].value.color); break;
                        case m3dpf_uint8:
                        case m3dpf_uint16:
                        case m3dpf_uint32: ptr += sprintf(ptr, "%s %d\r\n", sn, m->prop[i].value.num); break;
                        case m3dpf_float: ptr += sprintf(ptr, "%s %g\r\n", sn, m->prop[i].value.fnum); break;
                        case m3dpf_map:
                            if (m->prop[i].value.textureid < model->numtexture &&
                                    model->texture[m->prop[i].value.textureid].name) {
                                sl = _m3d_safestr(model->texture[m->prop[i].value.textureid].name, 0);
                                if (!sl) {
                                    setlocale(LC_NUMERIC, ol);
                                    goto memerr;
                                }
                                if (*sl)
                                    ptr += sprintf(ptr, "map_%s %s\r\n", sn, sl);
                                M3D_FREE(sn);
                                M3D_FREE(sl);
                                sl = NULL;
                            }
                            break;
                    }
                    sn = NULL;
                }
                ptr += sprintf(ptr, "\r\n");
            }
        }
        /* procedural face */
        if (model->numinlined && model->inlined && !(flags & M3D_EXP_NOFACE)) {
            /* all inlined assets which are not textures should be procedural surfaces */
            for (j = 0; j < model->numinlined; j++) {
                if (!model->inlined[j].name || !*model->inlined[j].name || !model->inlined[j].length || !model->inlined[j].data ||
                        (model->inlined[j].data[1] == 'P' && model->inlined[j].data[2] == 'N' && model->inlined[j].data[3] == 'G'))
                    continue;
                for (i = k = 0; i < model->numtexture; i++) {
                    if (!strcmp(model->inlined[j].name, model->texture[i].name)) {
                        k = 1;
                        break;
                    }
                }
                if (k) continue;
                sn = _m3d_safestr(model->inlined[j].name, 0);
                if (!sn) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr -= (uintptr_t)out;
                len = (unsigned int)((uintptr_t)ptr + (uintptr_t)strlen(sn) + (uintptr_t)18);
                out = (unsigned char *)M3D_REALLOC(out, len);
                ptr += (uintptr_t)out;
                if (!out) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr += sprintf(ptr, "Procedural\r\n%s\r\n\r\n", sn);
                M3D_FREE(sn);
                sn = NULL;
            }
        }
        /* mesh face */
        if (model->numface && face && !(flags & M3D_EXP_NOFACE)) {
            ptr -= (uintptr_t)out;
            len = (unsigned int)((uintptr_t)ptr + (uintptr_t)(model->numface * 128) + (uintptr_t)6);
            last = M3D_UNDEF;
            if (!(flags & M3D_EXP_NOMATERIAL))
                for (i = 0; i < model->numface; i++) {
                    j = face[i].data.materialid < model->nummaterial ? face[i].data.materialid : M3D_UNDEF;
                    if (j != last) {
                        last = j;
                        if (last < model->nummaterial)
                            len += (unsigned int)strlen(model->material[last].name);
                        len += 6;
                    }
                }
            out = (unsigned char *)M3D_REALLOC(out, len);
            ptr += (uintptr_t)out;
            if (!out) {
                setlocale(LC_NUMERIC, ol);
                goto memerr;
            }
            ptr += sprintf(ptr, "Mesh\r\n");
            last = M3D_UNDEF;
            for (i = 0; i < model->numface; i++) {
                j = face[i].data.materialid < model->nummaterial ? face[i].data.materialid : M3D_UNDEF;
                if (!(flags & M3D_EXP_NOMATERIAL) && j != last) {
                    last = j;
                    if (last < model->nummaterial) {
                        sn = _m3d_safestr(model->material[last].name, 0);
                        if (!sn) {
                            setlocale(LC_NUMERIC, ol);
                            goto memerr;
                        }
                        ptr += sprintf(ptr, "use %s\r\n", sn);
                        M3D_FREE(sn);
                        sn = NULL;
                    } else
                        ptr += sprintf(ptr, "use\r\n");
                }
                /* hardcoded triangles. Should be repeated as many times as the number of edges in polygon */
                for (j = 0; j < 3; j++) {
                    ptr += sprintf(ptr, "%s%d", j ? " " : "", vrtxidx[face[i].data.vertex[j]]);
                    k = M3D_NOTDEFINED;
                    if (!(flags & M3D_EXP_NOTXTCRD) && (face[i].data.texcoord[j] != M3D_UNDEF) &&
                            (tmapidx[face[i].data.texcoord[j]] != M3D_UNDEF)) {
                        k = tmapidx[face[i].data.texcoord[j]];
                        ptr += sprintf(ptr, "/%d", k);
                    }
                    if (!(flags & M3D_EXP_NONORMAL) && (face[i].data.normal[j] != M3D_UNDEF))
                        ptr += sprintf(ptr, "%s/%d", k == M3D_NOTDEFINED ? "/" : "", vrtxidx[face[i].data.normal[j]]);
                }
                ptr += sprintf(ptr, "\r\n");
            }
            ptr += sprintf(ptr, "\r\n");
        }
        /* mathematical shapes face */
        if (model->numshape && model->numshape && !(flags & M3D_EXP_NOFACE)) {
            for (j = 0; j < model->numshape; j++) {
                sn = _m3d_safestr(model->shape[j].name, 0);
                if (!sn) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr -= (uintptr_t)out;
                len = (unsigned int)((uintptr_t)ptr + (uintptr_t)strlen(sn) + (uintptr_t)33);
                out = (unsigned char *)M3D_REALLOC(out, len);
                ptr += (uintptr_t)out;
                if (!out) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr += sprintf(ptr, "Shape %s\r\n", sn);
                M3D_FREE(sn);
                sn = NULL;
                if (model->shape[j].group != M3D_UNDEF && !(flags & M3D_EXP_NOBONE))
                    ptr += sprintf(ptr, "group %d\r\n", model->shape[j].group);
                for (i = 0; i < model->shape[j].numcmd; i++) {
                    cmd = &model->shape[j].cmd[i];
                    if (cmd->type >= (unsigned int)(sizeof(m3d_commandtypes) / sizeof(m3d_commandtypes[0])) || !cmd->arg)
                        continue;
                    cd = &m3d_commandtypes[cmd->type];
                    ptr -= (uintptr_t)out;
                    len = (unsigned int)((uintptr_t)ptr + (uintptr_t)strlen(cd->key) + (uintptr_t)3);
                    for (k = 0; k < cd->p; k++)
                        switch (cd->a[k]) {
                            case m3dcp_mi_t:
                                if (cmd->arg[k] != M3D_NOTDEFINED) {
                                    len += (unsigned int)strlen(model->material[cmd->arg[k]].name) + 1;
                                }
                                break;
                            case m3dcp_va_t:
                                len += cmd->arg[k] * (cd->p - k - 1) * 16;
                                k = cd->p;
                                break;
                            default: len += 16; break;
                        }
                    out = (unsigned char *)M3D_REALLOC(out, len);
                    ptr += (uintptr_t)out;
                    if (!out) {
                        setlocale(LC_NUMERIC, ol);
                        goto memerr;
                    }
                    ptr += sprintf(ptr, "%s", cd->key);
                    for (k = n = 0, l = cd->p; k < l; k++) {
                        switch (cd->a[((k - n) % (cd->p - n)) + n]) {
                            case m3dcp_mi_t:
                                if (cmd->arg[k] != M3D_NOTDEFINED) {
                                    sn = _m3d_safestr(model->material[cmd->arg[k]].name, 0);
                                    if (!sn) {
                                        setlocale(LC_NUMERIC, ol);
                                        goto memerr;
                                    }
                                    ptr += sprintf(ptr, " %s", sn);
                                    M3D_FREE(sn);
                                    sn = NULL;
                                }
                                break;
                            case m3dcp_vc_t: ptr += sprintf(ptr, " %g", *((float *)&cmd->arg[k])); break;
                            case m3dcp_va_t:
                                ptr += sprintf(ptr, " %d[", cmd->arg[k]);
                                n = k + 1;
                                l += (cmd->arg[k] - 1) * (cd->p - k - 1);
                                break;
                            default: ptr += sprintf(ptr, " %d", cmd->arg[k]); break;
                        }
                    }
                    ptr += sprintf(ptr, "%s\r\n", l > cd->p ? " ]" : "");
                }
                ptr += sprintf(ptr, "\r\n");
            }
        }
        /* annotation labels */
        if (model->numlabel && model->label && !(flags & M3D_EXP_NOFACE)) {
            for (i = 0, j = 3, length = NULL; i < model->numlabel; i++) {
                if (model->label[i].name) j += (unsigned int)strlen(model->label[i].name);
                if (model->label[i].lang) j += (unsigned int)strlen(model->label[i].lang);
                if (model->label[i].text) j += (unsigned int)strlen(model->label[i].text);
                j += 40;
            }
            ptr -= (uintptr_t)out;
            len = (unsigned int)((uintptr_t)ptr + (uintptr_t)j);
            out = (unsigned char *)M3D_REALLOC(out, len);
            ptr += (uintptr_t)out;
            if (!out) {
                setlocale(LC_NUMERIC, ol);
                goto memerr;
            }
            for (i = 0; i < model->numlabel; i++) {
                if (!i || _m3d_strcmp(sl, model->label[i].lang) || _m3d_strcmp(sn, model->label[i].name)) {
                    sl = model->label[i].lang;
                    sn = model->label[i].name;
                    sd = _m3d_safestr(sn, 0);
                    if (!sd) {
                        setlocale(LC_NUMERIC, ol);
                        sn = sl = NULL;
                        goto memerr;
                    }
                    if (i) ptr += sprintf(ptr, "\r\n");
                    ptr += sprintf(ptr, "Labels %s\r\n", sd);
                    M3D_FREE(sd);
                    sd = NULL;
                    if (model->label[i].color)
                        ptr += sprintf(ptr, "color #0x%08x\r\n", model->label[i].color);
                    if (sl && *sl) {
                        sd = _m3d_safestr(sl, 0);
                        if (!sd) {
                            setlocale(LC_NUMERIC, ol);
                            sn = sl = NULL;
                            goto memerr;
                        }
                        ptr += sprintf(ptr, "lang %s\r\n", sd);
                        M3D_FREE(sd);
                        sd = NULL;
                    }
                }
                sd = _m3d_safestr(model->label[i].text, 2);
                if (!sd) {
                    setlocale(LC_NUMERIC, ol);
                    sn = sl = NULL;
                    goto memerr;
                }
                ptr += sprintf(ptr, "%d %s\r\n", model->label[i].vertexid, sd);
                M3D_FREE(sd);
                sd = NULL;
            }
            ptr += sprintf(ptr, "\r\n");
            sn = sl = NULL;
        }
        /* actions */
        if (model->numaction && model->action && !(flags & M3D_EXP_NOACTION)) {
            for (j = 0; j < model->numaction; j++) {
                a = &model->action[j];
                sn = _m3d_safestr(a->name, 0);
                if (!sn) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr -= (uintptr_t)out;
                len = (unsigned int)((uintptr_t)ptr + (uintptr_t)strlen(sn) + (uintptr_t)48);
                for (i = 0; i < a->numframe; i++)
                    len += a->frame[i].numtransform * 128 + 8;
                out = (unsigned char *)M3D_REALLOC(out, len);
                ptr += (uintptr_t)out;
                if (!out) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr += sprintf(ptr, "Action %d %s\r\n", a->durationmsec, sn);
                M3D_FREE(sn);
                sn = NULL;
                for (i = 0; i < a->numframe; i++) {
                    ptr += sprintf(ptr, "frame %d\r\n", a->frame[i].msec);
                    for (k = 0; k < a->frame[i].numtransform; k++) {
                        ptr += sprintf(ptr, "%d %d %d\r\n", a->frame[i].transform[k].boneid,
                                vrtxidx[a->frame[i].transform[k].pos], vrtxidx[a->frame[i].transform[k].ori]);
                    }
                }
                ptr += sprintf(ptr, "\r\n");
            }
        }
        /* inlined assets */
        if (model->numinlined && model->inlined) {
            for (i = j = 0; i < model->numinlined; i++)
                if (model->inlined[i].name)
                    j += (unsigned int)strlen(model->inlined[i].name) + 6;
            if (j > 0) {
                ptr -= (uintptr_t)out;
                len = (unsigned int)((uintptr_t)ptr + (uintptr_t)j + (uintptr_t)16);
                out = (unsigned char *)M3D_REALLOC(out, len);
                ptr += (uintptr_t)out;
                if (!out) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr += sprintf(ptr, "Assets\r\n");
                for (i = 0; i < model->numinlined; i++)
                    if (model->inlined[i].name)
                        ptr += sprintf(ptr, "%s%s\r\n", model->inlined[i].name, strrchr(model->inlined[i].name, '.') ? "" : ".png");
                ptr += sprintf(ptr, "\r\n");
            }
        }
        /* extra info */
        if (model->numextra && (flags & M3D_EXP_EXTRA)) {
            for (i = 0; i < model->numextra; i++) {
                if (model->extra[i]->length < 9) continue;
                ptr -= (uintptr_t)out;
                len = (unsigned int)((uintptr_t)ptr + (uintptr_t)17 + (uintptr_t)(model->extra[i]->length * 3));
                out = (unsigned char *)M3D_REALLOC(out, len);
                ptr += (uintptr_t)out;
                if (!out) {
                    setlocale(LC_NUMERIC, ol);
                    goto memerr;
                }
                ptr += sprintf(ptr, "Extra %c%c%c%c\r\n",
                        model->extra[i]->magic[0] > ' ' ? model->extra[i]->magic[0] : '_',
                        model->extra[i]->magic[1] > ' ' ? model->extra[i]->magic[1] : '_',
                        model->extra[i]->magic[2] > ' ' ? model->extra[i]->magic[2] : '_',
                        model->extra[i]->magic[3] > ' ' ? model->extra[i]->magic[3] : '_');
                for (j = 0; j < model->extra[i]->length; j++)
                    ptr += sprintf(ptr, "%02x ", *((unsigned char *)model->extra + sizeof(m3dchunk_t) + j));
                ptr--;
                ptr += sprintf(ptr, "\r\n\r\n");
            }
        }
        setlocale(LC_NUMERIC, ol);
        len = (unsigned int)((uintptr_t)ptr - (uintptr_t)out);
        out = (unsigned char *)M3D_REALLOC(out, len + 1);
        if (!out) goto memerr;
        out[len] = 0;
    } else
#endif
    {
        /* stricly only use LF (newline) in binary */
        sd = _m3d_safestr(model->desc, 3);
        if (!sd) goto memerr;
        /* header */
        h = (m3dhdr_t *)M3D_MALLOC(sizeof(m3dhdr_t) + strlen(sn) + strlen(sl) + strlen(sa) + strlen(sd) + 4);
        if (!h) goto memerr;
        memcpy((uint8_t *)h, "HEAD", 4);
        h->length = sizeof(m3dhdr_t);
        h->scale = scale;
        i = (unsigned int)strlen(sn);
        memcpy((uint8_t *)h + h->length, sn, i + 1);
        h->length += i + 1;
        M3D_FREE(sn);
        i = (unsigned int)strlen(sl);
        memcpy((uint8_t *)h + h->length, sl, i + 1);
        h->length += i + 1;
        M3D_FREE(sl);
        i = (unsigned int)strlen(sa);
        memcpy((uint8_t *)h + h->length, sa, i + 1);
        h->length += i + 1;
        M3D_FREE(sa);
        i = (unsigned int)strlen(sd);
        memcpy((uint8_t *)h + h->length, sd, i + 1);
        h->length += i + 1;
        M3D_FREE(sd);
        sn = sl = sa = sd = NULL;
        if (model->inlined)
            for (i = 0; i < model->numinlined; i++) {
                if (model->inlined[i].name && *model->inlined[i].name && model->inlined[i].length > 0) {
                    str = _m3d_addstr(str, &numstr, model->inlined[i].name);
                    if (!str) goto memerr;
                }
            }
        if (str)
            for (i = 0; i < numstr; i++) {
                h = _m3d_addhdr(h, &str[i]);
                if (!h) goto memerr;
            }
        vc_s = quality == M3D_EXP_INT8 ? 1 : (quality == M3D_EXP_INT16 ? 2 : (quality == M3D_EXP_DOUBLE ? 8 : 4));
        vi_s = maxvrtx < 254 ? 1 : (maxvrtx < 65534 ? 2 : 4);
        si_s = h->length - 16 < 254 ? 1 : (h->length - 16 < 65534 ? 2 : 4);
        ci_s = !numcmap || !cmap ? 0 : (numcmap < 254 ? 1 : (numcmap < 65534 ? 2 : 4));
        ti_s = !maxtmap || !tmap ? 0 : (maxtmap < 254 ? 1 : (maxtmap < 65534 ? 2 : 4));
        bi_s = !model->numbone || !model->bone || (flags & M3D_EXP_NOBONE) ? 0 : (model->numbone < 254 ? 1 : (model->numbone < 65534 ? 2 : 4));
        nb_s = maxbone < 2 ? 1 : (maxbone == 2 ? 2 : (maxbone <= 4 ? 4 : 8));
        sk_s = !bi_s || !maxskin || !skin ? 0 : (maxskin < 254 ? 1 : (maxskin < 65534 ? 2 : 4));
        fc_s = maxt < 254 ? 1 : (maxt < 65534 ? 2 : 4);
        hi_s = !model->numshape || !model->shape || (flags & M3D_EXP_NOFACE) ? 0 : (model->numshape < 254 ? 1 : (model->numshape < 65534 ? 2 : 4));
        fi_s = !model->numface || !model->face || (flags & M3D_EXP_NOFACE) ? 0 : (model->numface < 254 ? 1 : (model->numface < 65534 ? 2 : 4));
        h->types = (vc_s == 8 ? (3 << 0) : (vc_s == 2 ? (1 << 0) : (vc_s == 1 ? (0 << 0) : (2 << 0)))) |
                   (vi_s == 2 ? (1 << 2) : (vi_s == 1 ? (0 << 2) : (2 << 2))) |
                   (si_s == 2 ? (1 << 4) : (si_s == 1 ? (0 << 4) : (2 << 4))) |
                   (ci_s == 2 ? (1 << 6) : (ci_s == 1 ? (0 << 6) : (ci_s == 4 ? (2 << 6) : (3 << 6)))) |
                   (ti_s == 2 ? (1 << 8) : (ti_s == 1 ? (0 << 8) : (ti_s == 4 ? (2 << 8) : (3 << 8)))) |
                   (bi_s == 2 ? (1 << 10) : (bi_s == 1 ? (0 << 10) : (bi_s == 4 ? (2 << 10) : (3 << 10)))) |
                   (nb_s == 2 ? (1 << 12) : (nb_s == 1 ? (0 << 12) : (2 << 12))) |
                   (sk_s == 2 ? (1 << 14) : (sk_s == 1 ? (0 << 14) : (sk_s == 4 ? (2 << 14) : (3 << 14)))) |
                   (fc_s == 2 ? (1 << 16) : (fc_s == 1 ? (0 << 16) : (2 << 16))) |
                   (hi_s == 2 ? (1 << 18) : (hi_s == 1 ? (0 << 18) : (hi_s == 4 ? (2 << 18) : (3 << 18)))) |
                   (fi_s == 2 ? (1 << 20) : (fi_s == 1 ? (0 << 20) : (fi_s == 4 ? (2 << 20) : (3 << 20))));
        len = h->length;
        /* preview image chunk, must be the first if exists */
        if (model->preview.data && model->preview.length) {
            chunklen = 8 + model->preview.length;
            h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
            if (!h) goto memerr;
            memcpy((uint8_t *)h + len, "PRVW", 4);
            *((uint32_t *)((uint8_t *)h + len + 4)) = chunklen;
            memcpy((uint8_t *)h + len + 8, model->preview.data, model->preview.length);
            len += chunklen;
        }
        /* color map */
        if (numcmap && cmap && ci_s < 4 && !(flags & M3D_EXP_NOCMAP)) {
            chunklen = 8 + numcmap * sizeof(uint32_t);
            h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
            if (!h) goto memerr;
            memcpy((uint8_t *)h + len, "CMAP", 4);
            *((uint32_t *)((uint8_t *)h + len + 4)) = chunklen;
            memcpy((uint8_t *)h + len + 8, cmap, chunklen - 8);
            len += chunklen;
        } else
            numcmap = 0;
        /* texture map */
        if (numtmap && tmap && !(flags & M3D_EXP_NOTXTCRD) && !(flags & M3D_EXP_NOFACE)) {
            chunklen = 8 + maxtmap * vc_s * 2;
            h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
            if (!h) goto memerr;
            memcpy((uint8_t *)h + len, "TMAP", 4);
            length = (uint32_t *)((uint8_t *)h + len + 4);
            out = (uint8_t *)h + len + 8;
            last = M3D_UNDEF;
            for (i = 0; i < numtmap; i++) {
                if (tmap[i].newidx == last) continue;
                last = tmap[i].newidx;
                switch (vc_s) {
                    case 1:
                        *out++ = (uint8_t)(tmap[i].data.u * 255);
                        *out++ = (uint8_t)(tmap[i].data.v * 255);
                        break;
                    case 2:
                        *((uint16_t *)out) = (uint16_t)(tmap[i].data.u * 65535);
                        out += 2;
                        *((uint16_t *)out) = (uint16_t)(tmap[i].data.v * 65535);
                        out += 2;
                        break;
                    case 4:
                        *((float *)out) = tmap[i].data.u;
                        out += 4;
                        *((float *)out) = tmap[i].data.v;
                        out += 4;
                        break;
                    case 8:
                        *((double *)out) = tmap[i].data.u;
                        out += 8;
                        *((double *)out) = tmap[i].data.v;
                        out += 8;
                        break;
                }
            }
            *length = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
            out = NULL;
            len += *length;
        }
        /* vertex */
        if (numvrtx && vrtx) {
            chunklen = 8 + maxvrtx * (ci_s + sk_s + 4 * vc_s);
            h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
            if (!h) goto memerr;
            memcpy((uint8_t *)h + len, "VRTS", 4);
            length = (uint32_t *)((uint8_t *)h + len + 4);
            out = (uint8_t *)h + len + 8;
            last = M3D_UNDEF;
            for (i = 0; i < numvrtx; i++) {
                if (vrtx[i].newidx == last) continue;
                last = vrtx[i].newidx;
                switch (vc_s) {
                    case 1:
                        *out++ = (int8_t)(vrtx[i].data.x * 127);
                        *out++ = (int8_t)(vrtx[i].data.y * 127);
                        *out++ = (int8_t)(vrtx[i].data.z * 127);
                        *out++ = (int8_t)(vrtx[i].data.w * 127);
                        break;
                    case 2:
                        *((int16_t *)out) = (int16_t)(vrtx[i].data.x * 32767);
                        out += 2;
                        *((int16_t *)out) = (int16_t)(vrtx[i].data.y * 32767);
                        out += 2;
                        *((int16_t *)out) = (int16_t)(vrtx[i].data.z * 32767);
                        out += 2;
                        *((int16_t *)out) = (int16_t)(vrtx[i].data.w * 32767);
                        out += 2;
                        break;
                    case 4:
                        memcpy(out, &vrtx[i].data.x, sizeof(float));
                        out += 4;
                        memcpy(out, &vrtx[i].data.y, sizeof(float));
                        out += 4;
                        memcpy(out, &vrtx[i].data.z, sizeof(float));
                        out += 4;
                        memcpy(out, &vrtx[i].data.w, sizeof(float));
                        out += 4;
                        break;
                    case 8:
                        *((double *)out) = vrtx[i].data.x;
                        out += 8;
                        *((double *)out) = vrtx[i].data.y;
                        out += 8;
                        *((double *)out) = vrtx[i].data.z;
                        out += 8;
                        *((double *)out) = vrtx[i].data.w;
                        out += 8;
                        break;
                }
                idx = _m3d_cmapidx(cmap, numcmap, vrtx[i].data.color);
                switch (ci_s) {
                    case 1: *out++ = (uint8_t)(idx); break;
                    case 2:
                        *((uint16_t *)out) = (uint16_t)(idx);
                        out += 2;
                        break;
                    case 4:
                        *((uint32_t *)out) = vrtx[i].data.color;
                        out += 4;
                        break;
                }
                out = _m3d_addidx(out, sk_s, vrtx[i].data.skinid);
            }
            uint32_t v = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
            memcpy(length, &v, sizeof(uint32_t));
            //*length = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
            out = NULL;
            len += v;
        }
        /* bones chunk */
        if (model->numbone && model->bone && !(flags & M3D_EXP_NOBONE)) {
            i = 8 + bi_s + sk_s + model->numbone * (bi_s + si_s + 2 * vi_s);
            chunklen = i + numskin * nb_s * (bi_s + 1);
            h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
            if (!h) goto memerr;
            memcpy((uint8_t *)h + len, "BONE", 4);
            length = (uint32_t *)((uint8_t *)h + len + 4);
            out = (uint8_t *)h + len + 8;
            out = _m3d_addidx(out, bi_s, model->numbone);
            out = _m3d_addidx(out, sk_s, maxskin);
            for (i = 0; i < model->numbone; i++) {
                out = _m3d_addidx(out, bi_s, model->bone[i].parent);
                out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, model->bone[i].name));
                out = _m3d_addidx(out, vi_s, vrtxidx[model->bone[i].pos]);
                out = _m3d_addidx(out, vi_s, vrtxidx[model->bone[i].ori]);
            }
            if (numskin && skin && sk_s) {
                last = M3D_UNDEF;
                for (i = 0; i < numskin; i++) {
                    if (skin[i].newidx == last) continue;
                    last = skin[i].newidx;
                    memset(&weights, 0, nb_s);
                    for (j = 0; j < (uint32_t)nb_s && skin[i].data.boneid[j] != M3D_UNDEF &&
                                skin[i].data.weight[j] > (M3D_FLOAT)0.0;
                            j++)
                        weights[j] = (uint8_t)(skin[i].data.weight[j] * 255);
                    switch (nb_s) {
                        case 1: weights[0] = 255; break;
                        case 2:
                            *((uint16_t *)out) = *((uint16_t *)&weights[0]);
                            out += 2;
                            break;
                        case 4:
                            *((uint32_t *)out) = *((uint32_t *)&weights[0]);
                            out += 4;
                            break;
                        case 8:
                            *((uint64_t *)out) = *((uint64_t *)&weights[0]);
                            out += 8;
                            break;
                    }
                    for (j = 0; j < (uint32_t)nb_s && skin[i].data.boneid[j] != M3D_UNDEF && weights[j]; j++) {
                        out = _m3d_addidx(out, bi_s, skin[i].data.boneid[j]);
                        *length += bi_s;
                    }
                }
            }
            *length = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
            out = NULL;
            len += *length;
        }
        /* materials */
        if (model->nummaterial && !(flags & M3D_EXP_NOMATERIAL)) {
            for (j = 0; j < model->nummaterial; j++) {
                if (mtrlidx[j] == M3D_UNDEF || !model->material[j].numprop || !model->material[j].prop) continue;
                m = &model->material[j];
                chunklen = 12 + si_s + m->numprop * 5;
                h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
                if (!h) goto memerr;
                memcpy((uint8_t *)h + len, "MTRL", 4);
                length = (uint32_t *)((uint8_t *)h + len + 4);
                out = (uint8_t *)h + len + 8;
                out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, m->name));
                for (i = 0; i < m->numprop; i++) {
                    if (m->prop[i].type >= 128) {
                        if (m->prop[i].value.textureid >= model->numtexture ||
                                !model->texture[m->prop[i].value.textureid].name) continue;
                        k = m3dpf_map;
                    } else {
                        for (k = 256, l = 0; l < sizeof(m3d_propertytypes) / sizeof(m3d_propertytypes[0]); l++)
                            if (m->prop[i].type == m3d_propertytypes[l].id) {
                                k = m3d_propertytypes[l].format;
                                break;
                            }
                    }
                    if (k == 256) continue;
                    *out++ = m->prop[i].type;
                    switch (k) {
                        case m3dpf_color:
                            if (!(flags & M3D_EXP_NOCMAP)) {
                                idx = _m3d_cmapidx(cmap, numcmap, m->prop[i].value.color);
                                switch (ci_s) {
                                    case 1: *out++ = (uint8_t)(idx); break;
                                    case 2:
                                        *((uint16_t *)out) = (uint16_t)(idx);
                                        out += 2;
                                        break;
                                    case 4:
                                        *((uint32_t *)out) = (uint32_t)(m->prop[i].value.color);
                                        out += 4;
                                        break;
                                }
                            } else
                                out--;
                            break;
                        case m3dpf_uint8: *out++ = m->prop[i].value.num; break;
                        case m3dpf_uint16:
                            *((uint16_t *)out) = m->prop[i].value.num;
                            out += 2;
                            break;
                        case m3dpf_uint32:
                            *((uint32_t *)out) = m->prop[i].value.num;
                            out += 4;
                            break;
                        case m3dpf_float:
                            *((float *)out) = m->prop[i].value.fnum;
                            out += 4;
                            break;

                        case m3dpf_map:
                            idx = _m3d_stridx(str, numstr, model->texture[m->prop[i].value.textureid].name);
                            out = _m3d_addidx(out, si_s, idx);
                            break;
                    }
                }
                *length = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
                len += *length;
                out = NULL;
            }
        }
        /* procedural face */
        if (model->numinlined && model->inlined && !(flags & M3D_EXP_NOFACE)) {
            /* all inlined assets which are not textures should be procedural surfaces */
            for (j = 0; j < model->numinlined; j++) {
                if (!model->inlined[j].name || !model->inlined[j].name[0] || model->inlined[j].length < 4 ||
                        !model->inlined[j].data || (model->inlined[j].data[1] == 'P' && model->inlined[j].data[2] == 'N' && model->inlined[j].data[3] == 'G'))
                    continue;
                for (i = k = 0; i < model->numtexture; i++) {
                    if (!strcmp(model->inlined[j].name, model->texture[i].name)) {
                        k = 1;
                        break;
                    }
                }
                if (k) continue;
                numproc++;
                chunklen = 8 + si_s;
                h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
                if (!h) goto memerr;
                memcpy((uint8_t *)h + len, "PROC", 4);
                *((uint32_t *)((uint8_t *)h + len + 4)) = chunklen;
                out = (uint8_t *)h + len + 8;
                out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, model->inlined[j].name));
                out = NULL;
                len += chunklen;
            }
        }
        /* mesh face */
        if (model->numface && face && !(flags & M3D_EXP_NOFACE)) {
            chunklen = 8 + si_s + model->numface * (6 * vi_s + 3 * ti_s + si_s + 1);
            h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
            if (!h) goto memerr;
            memcpy((uint8_t *)h + len, "MESH", 4);
            length = (uint32_t *)((uint8_t *)h + len + 4);
            out = (uint8_t *)h + len + 8;
            last = M3D_UNDEF;
            for (i = 0; i < model->numface; i++) {
                if (!(flags & M3D_EXP_NOMATERIAL) && face[i].data.materialid != last) {
                    last = face[i].data.materialid;
                    idx = last < model->nummaterial ? _m3d_stridx(str, numstr, model->material[last].name) : 0;
                    *out++ = 0;
                    out = _m3d_addidx(out, si_s, idx);
                }
                /* hardcoded triangles. */
                k = (3 << 4) |
                    (((flags & M3D_EXP_NOTXTCRD) || !ti_s || face[i].data.texcoord[0] == M3D_UNDEF ||
                             face[i].data.texcoord[1] == M3D_UNDEF || face[i].data.texcoord[2] == M3D_UNDEF) ?
                                    0 :
                                    1) |
                    (((flags & M3D_EXP_NONORMAL) || face[i].data.normal[0] == M3D_UNDEF ||
                             face[i].data.normal[1] == M3D_UNDEF || face[i].data.normal[2] == M3D_UNDEF) ?
                                    0 :
                                    2);
                *out++ = k;
                for (j = 0; j < 3; j++) {
                    out = _m3d_addidx(out, vi_s, vrtxidx[face[i].data.vertex[j]]);
                    if (k & 1)
                        out = _m3d_addidx(out, ti_s, tmapidx[face[i].data.texcoord[j]]);
                    if (k & 2)
                        out = _m3d_addidx(out, vi_s, vrtxidx[face[i].data.normal[j]]);
                }
            }
            uint32_t v = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
            memcpy(length, &v, sizeof(uint32_t));
            len += v;
            out = NULL;
        }
        /* mathematical shapes face */
        if (model->numshape && model->shape && !(flags & M3D_EXP_NOFACE)) {
            for (j = 0; j < model->numshape; j++) {
                chunklen = 12 + si_s + model->shape[j].numcmd * (M3D_CMDMAXARG + 1) * 4;
                h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
                if (!h) goto memerr;
                memcpy((uint8_t *)h + len, "SHPE", 4);
                length = (uint32_t *)((uint8_t *)h + len + 4);
                out = (uint8_t *)h + len + 8;
                out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, model->shape[j].name));
                out = _m3d_addidx(out, bi_s, model->shape[j].group);
                for (i = 0; i < model->shape[j].numcmd; i++) {
                    cmd = &model->shape[j].cmd[i];
                    if (cmd->type >= (unsigned int)(sizeof(m3d_commandtypes) / sizeof(m3d_commandtypes[0])) || !cmd->arg)
                        continue;
                    cd = &m3d_commandtypes[cmd->type];
                    *out++ = (cmd->type & 0x7F) | (cmd->type > 127 ? 0x80 : 0);
                    if (cmd->type > 127) *out++ = (cmd->type >> 7) & 0xff;
                    for (k = n = 0, l = cd->p; k < l; k++) {
                        switch (cd->a[((k - n) % (cd->p - n)) + n]) {
                            case m3dcp_mi_t:
                                out = _m3d_addidx(out, si_s, cmd->arg[k] < model->nummaterial ? _m3d_stridx(str, numstr, model->material[cmd->arg[k]].name) : 0);
                                break;
                            case m3dcp_vc_t:
                                min_x = *((float *)&cmd->arg[k]);
                                switch (vc_s) {
                                    case 1: *out++ = (int8_t)(min_x * 127); break;
                                    case 2:
                                        *((int16_t *)out) = (int16_t)(min_x * 32767);
                                        out += 2;
                                        break;
                                    case 4:
                                        *((float *)out) = min_x;
                                        out += 4;
                                        break;
                                    case 8:
                                        *((double *)out) = min_x;
                                        out += 8;
                                        break;
                                }
                                break;
                            case m3dcp_hi_t: out = _m3d_addidx(out, hi_s, cmd->arg[k]); break;
                            case m3dcp_fi_t: out = _m3d_addidx(out, fi_s, cmd->arg[k]); break;
                            case m3dcp_ti_t: out = _m3d_addidx(out, ti_s, cmd->arg[k]); break;
                            case m3dcp_qi_t:
                            case m3dcp_vi_t: out = _m3d_addidx(out, vi_s, cmd->arg[k]); break;
                            case m3dcp_i1_t: out = _m3d_addidx(out, 1, cmd->arg[k]); break;
                            case m3dcp_i2_t: out = _m3d_addidx(out, 2, cmd->arg[k]); break;
                            case m3dcp_i4_t: out = _m3d_addidx(out, 4, cmd->arg[k]); break;
                            case m3dcp_va_t:
                                out = _m3d_addidx(out, 4, cmd->arg[k]);
                                n = k + 1;
                                l += (cmd->arg[k] - 1) * (cd->p - k - 1);
                                break;
                        }
                    }
                }
                uint32_t v = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
                memcpy( length, &v, sizeof(uint32_t));
                len += v;
                out = NULL;
            }
        }
        /* annotation labels */
        if (model->numlabel && model->label) {
            for (i = 0, length = NULL; i < model->numlabel; i++) {
                if (!i || _m3d_strcmp(sl, model->label[i].lang) || _m3d_strcmp(sn, model->label[i].name)) {
                    sl = model->label[i].lang;
                    sn = model->label[i].name;
                    if (length) {
                        *length = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
                        len += *length;
                    }
                    chunklen = 8 + 2 * si_s + ci_s + model->numlabel * (vi_s + si_s);
                    h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
                    if (!h) {
                        sn = NULL;
                        sl = NULL;
                        goto memerr;
                    }
                    memcpy((uint8_t *)h + len, "LBLS", 4);
                    length = (uint32_t *)((uint8_t *)h + len + 4);
                    out = (uint8_t *)h + len + 8;
                    out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, model->label[l].name));
                    out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, model->label[l].lang));
                    idx = _m3d_cmapidx(cmap, numcmap, model->label[i].color);
                    switch (ci_s) {
                        case 1: *out++ = (uint8_t)(idx); break;
                        case 2:
                            *((uint16_t *)out) = (uint16_t)(idx);
                            out += 2;
                            break;
                        case 4:
                            *((uint32_t *)out) = model->label[i].color;
                            out += 4;
                            break;
                    }
                }
                out = _m3d_addidx(out, vi_s, vrtxidx[model->label[i].vertexid]);
                out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, model->label[l].text));
            }
            if (length) {
                uint32_t v = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
                memcpy( length, &v, sizeof(uint32_t));                
                len += v;
            }
            out = NULL;
            sn = sl = NULL;
        }
        /* actions */
        if (model->numaction && model->action && model->numbone && model->bone && !(flags & M3D_EXP_NOACTION)) {
            for (j = 0; j < model->numaction; j++) {
                a = &model->action[j];
                chunklen = 14 + si_s + a->numframe * (4 + fc_s + maxt * (bi_s + 2 * vi_s));
                h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
                if (!h) goto memerr;
                memcpy((uint8_t *)h + len, "ACTN", 4);
                length = (uint32_t *)((uint8_t *)h + len + 4);
                out = (uint8_t *)h + len + 8;
                out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, a->name));
                *((uint16_t *)out) = (uint16_t)(a->numframe);
                out += 2;
                *((uint32_t *)out) = (uint32_t)(a->durationmsec);
                out += 4;
                for (i = 0; i < a->numframe; i++) {
                    *((uint32_t *)out) = (uint32_t)(a->frame[i].msec);
                    out += 4;
                    out = _m3d_addidx(out, fc_s, a->frame[i].numtransform);
                    for (k = 0; k < a->frame[i].numtransform; k++) {
                        out = _m3d_addidx(out, bi_s, a->frame[i].transform[k].boneid);
                        out = _m3d_addidx(out, vi_s, vrtxidx[a->frame[i].transform[k].pos]);
                        out = _m3d_addidx(out, vi_s, vrtxidx[a->frame[i].transform[k].ori]);
                    }
                }
                uint32_t v = (uint32_t)((uintptr_t)out - (uintptr_t)((uint8_t *)h + len));
                memcpy( length, &v, sizeof(uint32_t));                
                len += v;
                out = NULL;
            }
        }
        /* inlined assets */
        if (model->numinlined && model->inlined && (numproc || (flags & M3D_EXP_INLINE))) {
            for (j = 0; j < model->numinlined; j++) {
                if (!model->inlined[j].name || !model->inlined[j].name[0] || model->inlined[j].length < 4 || !model->inlined[j].data)
                    continue;
                if (!(flags & M3D_EXP_INLINE)) {
                    if (model->inlined[j].data[1] == 'P' && model->inlined[j].data[2] == 'N' && model->inlined[j].data[3] == 'G')
                        continue;
                    for (i = k = 0; i < model->numtexture; i++) {
                        if (!strcmp(model->inlined[j].name, model->texture[i].name)) {
                            k = 1;
                            break;
                        }
                    }
                    if (k) continue;
                }
                chunklen = 8 + si_s + model->inlined[j].length;
                h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
                if (!h) goto memerr;
                memcpy((uint8_t *)h + len, "ASET", 4);
                *((uint32_t *)((uint8_t *)h + len + 4)) = chunklen;
                out = (uint8_t *)h + len + 8;
                out = _m3d_addidx(out, si_s, _m3d_stridx(str, numstr, model->inlined[j].name));
                memcpy(out, model->inlined[j].data, model->inlined[j].length);
                out = NULL;
                len += chunklen;
            }
        }
        /* extra chunks */
        if (model->numextra && model->extra && (flags & M3D_EXP_EXTRA)) {
            for (j = 0; j < model->numextra; j++) {
                if (!model->extra[j] || model->extra[j]->length < 8)
                    continue;
                chunklen = model->extra[j]->length;
                h = (m3dhdr_t *)M3D_REALLOC(h, len + chunklen);
                if (!h) goto memerr;
                memcpy((uint8_t *)h + len, model->extra[j], chunklen);
                len += chunklen;
            }
        }
        /* add end chunk */
        h = (m3dhdr_t *)M3D_REALLOC(h, len + 4);
        if (!h) goto memerr;
        memcpy((uint8_t *)h + len, "OMD3", 4);
        len += 4;
        /* zlib compress */
        if (!(flags & M3D_EXP_NOZLIB)) {
            M3D_LOG("Deflating chunks");
            z = stbi_zlib_compress((unsigned char *)h, len, (int *)&l, 9);
            if (z && l > 0 && l < len) {
                len = l;
                M3D_FREE(h);
                h = (m3dhdr_t *)z;
            }
        }
        /* add file header at the begining */
        len += 8;
        out = (unsigned char *)M3D_MALLOC(len);
        if (!out) goto memerr;
        memcpy(out, "3DMO", 4);
        *((uint32_t *)(out + 4)) = len;
        memcpy(out + 8, h, len - 8);
    }
    if (size) *size = out ? len : 0;
    if (vrtxidx) M3D_FREE(vrtxidx);
    if (mtrlidx) M3D_FREE(mtrlidx);
    if (tmapidx) M3D_FREE(tmapidx);
    if (skinidx) M3D_FREE(skinidx);
    if (norm) M3D_FREE(norm);
    if (face) M3D_FREE(face);
    if (cmap) M3D_FREE(cmap);
    if (tmap) M3D_FREE(tmap);
    if (skin) M3D_FREE(skin);
    if (str) M3D_FREE(str);
    if (vrtx) M3D_FREE(vrtx);
    if (h) M3D_FREE(h);
    return out;
}
#endif

#endif

#ifdef __cplusplus
}
#ifdef M3D_CPPWRAPPER
#include <memory>
#include <string>
#include <vector>

/*** C++ wrapper class ***/
namespace M3D {
#ifdef M3D_IMPLEMENTATION

class Model {
public:
    m3d_t *model;

public:
    Model() {
        this->model = (m3d_t *)malloc(sizeof(m3d_t));
        memset(this->model, 0, sizeof(m3d_t));
    }
    Model(_unused const std::string &data, _unused m3dread_t ReadFileCB,
            _unused m3dfree_t FreeCB, _unused M3D::Model mtllib) {
#ifndef M3D_NOIMPORTER
        this->model = m3d_load((unsigned char *)data.data(), ReadFileCB, FreeCB, mtllib.model);
#else
        Model();
#endif
    }
    Model(_unused const std::vector<unsigned char> data, _unused m3dread_t ReadFileCB,
            _unused m3dfree_t FreeCB, _unused M3D::Model mtllib) {
#ifndef M3D_NOIMPORTER
        this->model = m3d_load((unsigned char *)&data[0], ReadFileCB, FreeCB, mtllib.model);
#else
        Model();
#endif
    }
    Model(_unused const unsigned char *data, _unused m3dread_t ReadFileCB,
            _unused m3dfree_t FreeCB, _unused M3D::Model mtllib) {
#ifndef M3D_NOIMPORTER
        this->model = m3d_load((unsigned char *)data, ReadFileCB, FreeCB, mtllib.model);
#else
        Model();
#endif
    }
    ~Model() { m3d_free(this->model); }

public:
    m3d_t *getCStruct() { return this->model; }
    std::string getName() { return std::string(this->model->name); }
    void setName(std::string name) { this->model->name = (char *)name.c_str(); }
    std::string getLicense() { return std::string(this->model->license); }
    void setLicense(std::string license) { this->model->license = (char *)license.c_str(); }
    std::string getAuthor() { return std::string(this->model->author); }
    void setAuthor(std::string author) { this->model->author = (char *)author.c_str(); }
    std::string getDescription() { return std::string(this->model->desc); }
    void setDescription(std::string desc) { this->model->desc = (char *)desc.c_str(); }
    float getScale() { return this->model->scale; }
    void setScale(float scale) { this->model->scale = scale; }
    std::vector<unsigned char> getPreview() { return this->model->preview.data ?
                                                             std::vector<unsigned char>(this->model->preview.data, this->model->preview.data + this->model->preview.length) :
                                                             std::vector<unsigned char>(); }
    std::vector<uint32_t> getColorMap() { return this->model->cmap ? std::vector<uint32_t>(this->model->cmap,
                                                                             this->model->cmap + this->model->numcmap) :
                                                                     std::vector<uint32_t>(); }
    std::vector<m3dti_t> getTextureMap() { return this->model->tmap ? std::vector<m3dti_t>(this->model->tmap,
                                                                              this->model->tmap + this->model->numtmap) :
                                                                      std::vector<m3dti_t>(); }
    std::vector<m3dtx_t> getTextures() { return this->model->texture ? std::vector<m3dtx_t>(this->model->texture,
                                                                               this->model->texture + this->model->numtexture) :
                                                                       std::vector<m3dtx_t>(); }
    std::string getTextureName(int idx) { return idx >= 0 && (unsigned int)idx < this->model->numtexture ?
                                                         std::string(this->model->texture[idx].name) :
                                                         nullptr; }
    std::vector<m3db_t> getBones() { return this->model->bone ? std::vector<m3db_t>(this->model->bone, this->model->bone +
                                                                                                               this->model->numbone) :
                                                                std::vector<m3db_t>(); }
    std::string getBoneName(int idx) { return idx >= 0 && (unsigned int)idx < this->model->numbone ?
                                                      std::string(this->model->bone[idx].name) :
                                                      nullptr; }
    std::vector<m3dm_t> getMaterials() { return this->model->material ? std::vector<m3dm_t>(this->model->material,
                                                                                this->model->material + this->model->nummaterial) :
                                                                        std::vector<m3dm_t>(); }
    std::string getMaterialName(int idx) { return idx >= 0 && (unsigned int)idx < this->model->nummaterial ?
                                                          std::string(this->model->material[idx].name) :
                                                          nullptr; }
    int getMaterialPropertyInt(int idx, int type) {
        if (idx < 0 || (unsigned int)idx >= this->model->nummaterial || type < 0 || type >= 127 ||
                !this->model->material[idx].prop) return -1;
        for (int i = 0; i < this->model->material[idx].numprop; i++) {
            if (this->model->material[idx].prop[i].type == type)
                return this->model->material[idx].prop[i].value.num;
        }
        return -1;
    }
    uint32_t getMaterialPropertyColor(int idx, int type) { return this->getMaterialPropertyInt(idx, type); }
    float getMaterialPropertyFloat(int idx, int type) {
        if (idx < 0 || (unsigned int)idx >= this->model->nummaterial || type < 0 || type >= 127 ||
                !this->model->material[idx].prop) return -1.0f;
        for (int i = 0; i < this->model->material[idx].numprop; i++) {
            if (this->model->material[idx].prop[i].type == type)
                return this->model->material[idx].prop[i].value.fnum;
        }
        return -1.0f;
    }
    m3dtx_t *getMaterialPropertyMap(int idx, int type) {
        if (idx < 0 || (unsigned int)idx >= this->model->nummaterial || type < 128 || type > 255 ||
                !this->model->material[idx].prop) return nullptr;
        for (int i = 0; i < this->model->material[idx].numprop; i++) {
            if (this->model->material[idx].prop[i].type == type)
                return this->model->material[idx].prop[i].value.textureid < this->model->numtexture ?
                               &this->model->texture[this->model->material[idx].prop[i].value.textureid] :
                               nullptr;
        }
        return nullptr;
    }
    std::vector<m3dv_t> getVertices() { return this->model->vertex ? std::vector<m3dv_t>(this->model->vertex,
                                                                             this->model->vertex + this->model->numvertex) :
                                                                     std::vector<m3dv_t>(); }
    std::vector<m3df_t> getFace() { return this->model->face ? std::vector<m3df_t>(this->model->face, this->model->face +
                                                                                                              this->model->numface) :
                                                               std::vector<m3df_t>(); }
    std::vector<m3dh_t> getShape() { return this->model->shape ? std::vector<m3dh_t>(this->model->shape,
                                                                         this->model->shape + this->model->numshape) :
                                                                 std::vector<m3dh_t>(); }
    std::string getShapeName(int idx) { return idx >= 0 && (unsigned int)idx < this->model->numshape &&
                                                               this->model->shape[idx].name && this->model->shape[idx].name[0] ?
                                                       std::string(this->model->shape[idx].name) :
                                                       nullptr; }
    unsigned int getShapeGroup(int idx) { return idx >= 0 && (unsigned int)idx < this->model->numshape ?
                                                         this->model->shape[idx].group :
                                                         0xFFFFFFFF; }
    std::vector<m3dc_t> getShapeCommands(int idx) { return idx >= 0 && (unsigned int)idx < this->model->numshape &&
                                                                           this->model->shape[idx].cmd ?
                                                                   std::vector<m3dc_t>(this->model->shape[idx].cmd, this->model->shape[idx].cmd +
                                                                                                                            this->model->shape[idx].numcmd) :
                                                                   std::vector<m3dc_t>(); }
    std::vector<m3dl_t> getAnnotationLabels() { return this->model->label ? std::vector<m3dl_t>(this->model->label,
                                                                                    this->model->label + this->model->numlabel) :
                                                                            std::vector<m3dl_t>(); }
    std::vector<m3ds_t> getSkin() { return this->model->skin ? std::vector<m3ds_t>(this->model->skin, this->model->skin +
                                                                                                              this->model->numskin) :
                                                               std::vector<m3ds_t>(); }
    std::vector<m3da_t> getActions() { return this->model->action ? std::vector<m3da_t>(this->model->action,
                                                                            this->model->action + this->model->numaction) :
                                                                    std::vector<m3da_t>(); }
    std::string getActionName(int aidx) { return aidx >= 0 && (unsigned int)aidx < this->model->numaction ?
                                                         std::string(this->model->action[aidx].name) :
                                                         nullptr; }
    unsigned int getActionDuration(int aidx) { return aidx >= 0 && (unsigned int)aidx < this->model->numaction ?
                                                              this->model->action[aidx].durationmsec :
                                                              0; }
    std::vector<m3dfr_t> getActionFrames(int aidx) { return aidx >= 0 && (unsigned int)aidx < this->model->numaction ?
                                                                    std::vector<m3dfr_t>(this->model->action[aidx].frame, this->model->action[aidx].frame +
                                                                                                                                  this->model->action[aidx].numframe) :
                                                                    std::vector<m3dfr_t>(); }
    unsigned int getActionFrameTimestamp(int aidx, int fidx) { return aidx >= 0 && (unsigned int)aidx < this->model->numaction ?
                                                                              (fidx >= 0 && (unsigned int)fidx < this->model->action[aidx].numframe ?
                                                                                              this->model->action[aidx].frame[fidx].msec :
                                                                                              0) :
                                                                              0; }
    std::vector<m3dtr_t> getActionFrameTransforms(int aidx, int fidx) {
        return aidx >= 0 && (unsigned int)aidx < this->model->numaction ? (
                                                                                  fidx >= 0 && (unsigned int)fidx < this->model->action[aidx].numframe ?
                                                                                          std::vector<m3dtr_t>(this->model->action[aidx].frame[fidx].transform,
                                                                                                  this->model->action[aidx].frame[fidx].transform + this->model->action[aidx].frame[fidx].numtransform) :
                                                                                          std::vector<m3dtr_t>()) :
                                                                          std::vector<m3dtr_t>();
    }
    std::vector<m3dtr_t> getActionFrame(int aidx, int fidx, std::vector<m3dtr_t> skeleton) {
        m3dtr_t *pose = m3d_frame(this->model, (unsigned int)aidx, (unsigned int)fidx,
                skeleton.size() ? &skeleton[0] : nullptr);
        return std::vector<m3dtr_t>(pose, pose + this->model->numbone);
    }
    std::vector<m3db_t> getActionPose(int aidx, unsigned int msec) {
        m3db_t *pose = m3d_pose(this->model, (unsigned int)aidx, (unsigned int)msec);
        return std::vector<m3db_t>(pose, pose + this->model->numbone);
    }
    std::vector<m3di_t> getInlinedAssets() { return this->model->inlined ? std::vector<m3di_t>(this->model->inlined,
                                                                                   this->model->inlined + this->model->numinlined) :
                                                                           std::vector<m3di_t>(); }
    std::vector<std::unique_ptr<m3dchunk_t>> getExtras() { return this->model->extra ?
                                                                          std::vector<std::unique_ptr<m3dchunk_t>>(this->model->extra,
                                                                                  this->model->extra + this->model->numextra) :
                                                                          std::vector<std::unique_ptr<m3dchunk_t>>(); }
    std::vector<unsigned char> Save(_unused int quality, _unused int flags) {
#ifdef M3D_EXPORTER
        unsigned int size;
        unsigned char *ptr = m3d_save(this->model, quality, flags, &size);
        return ptr && size ? std::vector<unsigned char>(ptr, ptr + size) : std::vector<unsigned char>();
#else
        return std::vector<unsigned char>();
#endif
    }
};

#else
class Model {
public:
    m3d_t *model;

public:
    Model(const std::string &data, m3dread_t ReadFileCB, m3dfree_t FreeCB);
    Model(const std::vector<unsigned char> data, m3dread_t ReadFileCB, m3dfree_t FreeCB);
    Model(const unsigned char *data, m3dread_t ReadFileCB, m3dfree_t FreeCB);
    Model();
    ~Model();

public:
    m3d_t *getCStruct();
    std::string getName();
    void setName(std::string name);
    std::string getLicense();
    void setLicense(std::string license);
    std::string getAuthor();
    void setAuthor(std::string author);
    std::string getDescription();
    void setDescription(std::string desc);
    float getScale();
    void setScale(float scale);
    std::vector<unsigned char> getPreview();
    std::vector<uint32_t> getColorMap();
    std::vector<m3dti_t> getTextureMap();
    std::vector<m3dtx_t> getTextures();
    std::string getTextureName(int idx);
    std::vector<m3db_t> getBones();
    std::string getBoneName(int idx);
    std::vector<m3dm_t> getMaterials();
    std::string getMaterialName(int idx);
    int getMaterialPropertyInt(int idx, int type);
    uint32_t getMaterialPropertyColor(int idx, int type);
    float getMaterialPropertyFloat(int idx, int type);
    m3dtx_t *getMaterialPropertyMap(int idx, int type);
    std::vector<m3dv_t> getVertices();
    std::vector<m3df_t> getFace();
    std::vector<m3dh_t> getShape();
    std::string getShapeName(int idx);
    unsigned int getShapeGroup(int idx);
    std::vector<m3dc_t> getShapeCommands(int idx);
    std::vector<m3dl_t> getAnnotationLabels();
    std::vector<m3ds_t> getSkin();
    std::vector<m3da_t> getActions();
    std::string getActionName(int aidx);
    unsigned int getActionDuration(int aidx);
    std::vector<m3dfr_t> getActionFrames(int aidx);
    unsigned int getActionFrameTimestamp(int aidx, int fidx);
    std::vector<m3dtr_t> getActionFrameTransforms(int aidx, int fidx);
    std::vector<m3dtr_t> getActionFrame(int aidx, int fidx, std::vector<m3dtr_t> skeleton);
    std::vector<m3db_t> getActionPose(int aidx, unsigned int msec);
    std::vector<m3di_t> getInlinedAssets();
    std::vector<std::unique_ptr<m3dchunk_t>> getExtras();
    std::vector<unsigned char> Save(int quality, int flags);
};

#endif /* impl */
} // namespace M3D

#ifdef _WIN32
#    pragma warning(pop)
#endif // _WIN32

#endif

#endif /* __cplusplus */

#endif