Added support to load Half-Life 1 MDL files.

Added code to use Half-Life 1 MDL loader in MDLLoader.cpp.
Added Half-Life 1 MDL loader files to CMakeLists.
Added new options in config.h to use with Half-Life 1 MDL loader.

code/CMakeLists.txt

@@ -454,6 +454,16 @@ ADD_ASSIMP_IMPORTER( MDL
   MDL/MDLLoader.cpp
   MDL/MDLLoader.h
   MDL/MDLMaterialLoader.cpp
+  MDL/HalfLife/HalfLifeMDLBaseHeader.h
+  MDL/HalfLife/HL1FileData.h
+  MDL/HalfLife/HL1MDLLoader.cpp
+  MDL/HalfLife/HL1MDLLoader.h
+  MDL/HalfLife/HL1ImportDefinitions.h
+  MDL/HalfLife/HL1ImportSettings.h
+  MDL/HalfLife/HL1MeshTrivert.h
+  MDL/HalfLife/LogFunctions.h
+  MDL/HalfLife/UniqueNameGenerator.cpp
+  MDL/HalfLife/UniqueNameGenerator.h
 )
 
 SET( MaterialSystem_SRCS

code/MDL/HalfLife/HL1FileData.h

@@ -0,0 +1,355 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  HL1FileData.h
+ *  @brief Definition of in-memory structures for the
+ *        Half-Life 1 MDL file format.
+ */
+
+#ifndef AI_HL1FILEDATA_INCLUDED
+#define AI_HL1FILEDATA_INCLUDED
+
+#include "HalfLifeMDLBaseHeader.h"
+
+#include <assimp/Compiler/pushpack1.h>
+#include <assimp/types.h>
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+using vec3_t = float[3];
+
+struct Header_HL1 : HalfLifeMDLBaseHeader {
+    char name[64];
+    int32_t length;
+
+    vec3_t eyeposition; // ideal eye position
+    vec3_t min; // ideal movement hull size
+    vec3_t max;
+
+    vec3_t bbmin; // clipping bounding box
+    vec3_t bbmax;
+
+    int32_t unused; // was flags
+
+    int32_t numbones; // bones
+    int32_t boneindex;
+
+    int32_t numbonecontrollers; // bone controllers
+    int32_t bonecontrollerindex;
+
+    int32_t numhitboxes; // complex bounding boxes
+    int32_t hitboxindex;
+
+    int32_t numseq; // animation sequences
+    int32_t seqindex;
+
+    int32_t numseqgroups; // demand loaded sequences
+    int32_t seqgroupindex;
+
+    int32_t numtextures; // raw textures
+    int32_t textureindex;
+    int32_t texturedataindex;
+
+    int32_t numskinref; // replaceable textures
+    int32_t numskinfamilies;
+    int32_t skinindex;
+
+    int32_t numbodyparts;
+    int32_t bodypartindex;
+
+    int32_t numattachments; // queryable attachable points
+    int32_t attachmentindex;
+
+    int32_t unused2; // was "soundtable"
+    int32_t unused3; // was "soundindex"
+    int32_t unused4; // was "soundgroups"
+    int32_t unused5; // was "soundgroupindex"
+
+    int32_t numtransitions; // animation node to animation node transition graph
+    int32_t transitionindex;
+} PACK_STRUCT;
+
+// header for demand loaded sequence group data
+struct SequenceHeader_HL1 : HalfLifeMDLBaseHeader {
+    char name[64];
+    int32_t length;
+} PACK_STRUCT;
+
+// bones
+struct Bone_HL1 {
+    char name[32]; // bone name for symbolic links
+    int32_t parent; // parent bone
+    int32_t unused; // was "flags" -- ??
+    int32_t bonecontroller[6]; // bone controller index, -1 == none
+    float value[6]; // default DoF values
+    float scale[6]; // scale for delta DoF values
+} PACK_STRUCT;
+
+// bone controllers
+struct BoneController_HL1 {
+    int32_t bone; // -1 == 0
+    int32_t type; // X, Y, Z, XR, YR, ZR, M
+    float start;
+    float end;
+    int32_t unused; // was "rest" - byte index value at rest
+    int32_t index; // 0-3 user set controller, 4 mouth
+} PACK_STRUCT;
+
+// intersection boxes
+struct Hitbox_HL1 {
+    int32_t bone;
+    int32_t group; // intersection group
+    vec3_t bbmin; // bounding box
+    vec3_t bbmax;
+} PACK_STRUCT;
+
+//
+// demand loaded sequence groups
+//
+struct SequenceGroup_HL1 {
+    char label[32]; // textual name
+    char name[64]; // file name
+    int32_t unused; // was "cache"  - index pointer
+    int32_t unused2; // was "data" -  hack for group 0
+} PACK_STRUCT;
+
+// The type of blending for a sequence.
+enum SequenceBlendMode_HL1 {
+    NoBlend = 1,
+    TwoWayBlending = 2,
+    FourWayBlending = 4,
+};
+
+// sequence descriptions
+struct SequenceDesc_HL1 {
+    char label[32]; // sequence label
+
+    float fps; // frames per second
+    int32_t flags; // looping/non-looping flags
+
+    int32_t activity;
+    int32_t actweight;
+
+    int32_t numevents;
+    int32_t eventindex;
+
+    int32_t numframes; // number of frames per sequence
+
+    int32_t unused; // was "numpivots" - number of foot pivots
+    int32_t unused2; // was "pivotindex"
+
+    int32_t motiontype;
+    int32_t motionbone;
+    vec3_t linearmovement;
+    int32_t unused3; // was "automoveposindex"
+    int32_t unused4; // was "automoveangleindex"
+
+    vec3_t bbmin; // per sequence bounding box
+    vec3_t bbmax;
+
+    int32_t numblends;
+    int32_t animindex; // mstudioanim_t pointer relative to start of sequence group data
+                   // [blend][bone][X, Y, Z, XR, YR, ZR]
+
+    int32_t blendtype[2]; // X, Y, Z, XR, YR, ZR
+    float blendstart[2]; // starting value
+    float blendend[2]; // ending value
+    int32_t unused5; // was "blendparent"
+
+    int32_t seqgroup; // sequence group for demand loading
+
+    int32_t entrynode; // transition node at entry
+    int32_t exitnode; // transition node at exit
+    int32_t nodeflags; // transition rules
+
+    int32_t unused6; // was "nextseq" - auto advancing sequences
+} PACK_STRUCT;
+
+// events
+struct AnimEvent_HL1 {
+    int32_t frame;
+    int32_t event;
+    int32_t unused; // was "type"
+    char options[64];
+} PACK_STRUCT;
+
+// attachment
+struct Attachment_HL1 {
+    char unused[32]; // was "name"
+    int32_t unused2; // was "type"
+    int32_t bone;
+    vec3_t org; // attachment point
+    vec3_t unused3[3]; // was "vectors"
+} PACK_STRUCT;
+
+struct AnimValueOffset_HL1 {
+    unsigned short offset[6];
+} PACK_STRUCT;
+
+// animation frames
+union AnimValue_HL1 {
+    struct {
+        uint8_t valid;
+        uint8_t total;
+    } num PACK_STRUCT;
+    short value;
+} PACK_STRUCT;
+
+// body part index
+struct Bodypart_HL1 {
+    char name[64];
+    int32_t nummodels;
+    int32_t base;
+    int32_t modelindex; // index into models array
+} PACK_STRUCT;
+
+// skin info
+struct Texture_HL1 {
+    char name[64];
+    int32_t flags;
+    int32_t width;
+    int32_t height;
+    int32_t index;
+} PACK_STRUCT;
+
+// studio models
+struct Model_HL1 {
+    char name[64];
+
+    int32_t unused; // was "type"
+
+    float unused2; // was "boundingradius"
+
+    int32_t nummesh;
+    int32_t meshindex;
+
+    int32_t numverts; // number of unique vertices
+    int32_t vertinfoindex; // vertex bone info
+    int32_t vertindex; // vertex vec3_t
+    int32_t numnorms; // number of unique surface normals
+    int32_t norminfoindex; // normal bone info
+    int32_t normindex; // normal vec3_t
+
+    int32_t unused3; // was "numgroups" - deformation groups
+    int32_t unused4; // was "groupindex"
+} PACK_STRUCT;
+
+// meshes
+struct Mesh_HL1 {
+    int32_t numtris;
+    int32_t triindex;
+    int32_t skinref;
+    int32_t numnorms; // per mesh normals
+    int32_t unused; // was "normindex" - normal vec3_t
+} PACK_STRUCT;
+
+struct Trivert {
+    short vertindex; // index into vertex array
+    short normindex; // index into normal array
+    short s, t; // s,t position on skin
+} PACK_STRUCT;
+
+#include <assimp/Compiler/poppack1.h>
+
+#if (!defined AI_MDL_HL1_VERSION)
+#define AI_MDL_HL1_VERSION 10
+#endif
+#if (!defined AI_MDL_HL1_MAX_TRIANGLES)
+#define AI_MDL_HL1_MAX_TRIANGLES 20000
+#endif
+#if (!defined AI_MDL_HL1_MAX_VERTICES)
+#define AI_MDL_HL1_MAX_VERTICES 2048
+#endif
+#if (!defined AI_MDL_HL1_MAX_SEQUENCES)
+#define AI_MDL_HL1_MAX_SEQUENCES 2048
+#endif
+#if (!defined AI_MDL_HL1_MAX_SEQUENCE_GROUPS)
+#define AI_MDL_HL1_MAX_SEQUENCE_GROUPS 32
+#endif
+#if (!defined AI_MDL_HL1_MAX_TEXTURES)
+#define AI_MDL_HL1_MAX_TEXTURES 100
+#endif
+#if (!defined AI_MDL_HL1_MAX_SKIN_FAMILIES)
+#define AI_MDL_HL1_MAX_SKIN_FAMILIES 100
+#endif
+#if (!defined AI_MDL_HL1_MAX_BONES)
+#define AI_MDL_HL1_MAX_BONES 128
+#endif
+#if (!defined AI_MDL_HL1_MAX_BODYPARTS)
+#define AI_MDL_HL1_MAX_BODYPARTS 32
+#endif
+#if (!defined AI_MDL_HL1_MAX_MODELS)
+#define AI_MDL_HL1_MAX_MODELS 32
+#endif
+#if (!defined AI_MDL_HL1_MAX_MESHES)
+#define AI_MDL_HL1_MAX_MESHES 256
+#endif
+#if (!defined AI_MDL_HL1_MAX_EVENTS)
+#define AI_MDL_HL1_MAX_EVENTS 1024
+#endif
+#if (!defined AI_MDL_HL1_MAX_BONE_CONTROLLERS)
+#define AI_MDL_HL1_MAX_BONE_CONTROLLERS 8
+#endif
+#if (!defined AI_MDL_HL1_MAX_ATTACHMENTS)
+#define AI_MDL_HL1_MAX_ATTACHMENTS 512
+#endif
+
+// lighting options
+#if (!defined AI_MDL_HL1_STUDIO_NF_FLATSHADE)
+#define AI_MDL_HL1_STUDIO_NF_FLATSHADE 0x0001
+#endif
+#if (!defined AI_MDL_HL1_STUDIO_NF_CHROME)
+#define AI_MDL_HL1_STUDIO_NF_CHROME 0x0002
+#endif
+#if (!defined AI_MDL_HL1_STUDIO_NF_ADDITIVE)
+#define AI_MDL_HL1_STUDIO_NF_ADDITIVE 0x0020
+#endif
+#if (!defined AI_MDL_HL1_STUDIO_NF_MASKED)
+#define AI_MDL_HL1_STUDIO_NF_MASKED 0x0040
+#endif
+
+} // namespace HalfLife
+} // namespace MDL
+} // namespace Assimp
+
+#endif // AI_HL1FILEDATA_INCLUDED

code/MDL/HalfLife/HL1ImportDefinitions.h

@@ -0,0 +1,64 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file HL1ImportDefinitions.h
+ *  @brief HL1 MDL loader specific definitions.
+ */
+
+#ifndef AI_MDL_HL1_IMPORT_DEFINITIONS_INCLUDED
+#define AI_MDL_HL1_IMPORT_DEFINITIONS_INCLUDED
+
+#define AI_MDL_HL1_NODE_ROOT "<MDL_root>"
+#define AI_MDL_HL1_NODE_BODYPARTS "<MDL_bodyparts>"
+#define AI_MDL_HL1_NODE_BONES "<MDL_bones>"
+#define AI_MDL_HL1_NODE_BONE_CONTROLLERS "<MDL_bone_controllers>"
+#define AI_MDL_HL1_NODE_SEQUENCE_INFOS "<MDL_sequence_infos>"
+#define AI_MDL_HL1_NODE_SEQUENCE_GROUPS "<MDL_sequence_groups>"
+#define AI_MDL_HL1_NODE_SEQUENCE_TRANSITION_GRAPH "<MDL_sequence_transition_graph>"
+#define AI_MDL_HL1_NODE_ATTACHMENTS "<MDL_attachments>"
+#define AI_MDL_HL1_NODE_HITBOXES "<MDL_hitboxes>"
+#define AI_MDL_HL1_NODE_GLOBAL_INFO "<MDL_global_info>"
+#define AI_MDL_HL1_NODE_ANIMATION_EVENTS "AnimationEvents"
+#define AI_MDL_HL1_NODE_BLEND_CONTROLLERS "BlendControllers"
+
+#define AI_MDL_HL1_MATKEY_CHROME(type, N) "$mat.HL1.chrome", type, N
+
+#endif // AI_MDL_HL1_IMPORT_DEFINITIONS_INCLUDED

code/MDL/HalfLife/HL1ImportSettings.h

@@ -0,0 +1,85 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file HL1ImportSettings.h
+ *  @brief Half-Life 1 MDL loader configuration settings.
+ */
+
+#ifndef AI_HL1IMPORTSETTINGS_INCLUDED
+#define AI_HL1IMPORTSETTINGS_INCLUDED
+
+#include <string>
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+struct HL1ImportSettings {
+    HL1ImportSettings() :
+        read_animations(false),
+        read_animation_events(false),
+        read_blend_controllers(false),
+        read_sequence_groups_info(false),
+        read_sequence_transitions(false),
+        read_attachments(false),
+        read_bone_controllers(false),
+        read_hitboxes(false),
+        read_textures(false),
+        read_misc_global_info(false) {
+    }
+
+    bool read_animations;
+    bool read_animation_events;
+    bool read_blend_controllers;
+    bool read_sequence_groups_info;
+    bool read_sequence_transitions;
+    bool read_attachments;
+    bool read_bone_controllers;
+    bool read_hitboxes;
+    bool read_textures;
+    bool read_misc_global_info;
+};
+
+} // namespace HalfLife
+} // namespace MDL
+} // namespace Assimp
+
+#endif // AI_HL1IMPORTSETTINGS_INCLUDED

code/MDL/HalfLife/HL1MDLLoader.h

@@ -0,0 +1,235 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file HL1MDLLoader.h
+ *  @brief Declaration of the Half-Life 1 MDL loader.
+ */
+
+#ifndef AI_HL1MDLLOADER_INCLUDED
+#define AI_HL1MDLLOADER_INCLUDED
+
+#include "HL1FileData.h"
+#include "HL1ImportSettings.h"
+#include "UniqueNameGenerator.h"
+
+#include <assimp/scene.h>
+#include <assimp/texture.h>
+#include <assimp/IOSystem.hpp>
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+class HL1MDLLoader {
+public:
+    HL1MDLLoader() = delete;
+    HL1MDLLoader(const HL1MDLLoader &) = delete;
+
+    /** See variables descriptions at the end for more details. */
+    HL1MDLLoader(
+        aiScene *scene,
+        IOSystem *io,
+        const unsigned char *buffer,
+        const std::string &file_path,
+        const HL1ImportSettings &import_settings);
+
+    ~HL1MDLLoader();
+
+    void load_file();
+
+protected:
+    /** \brief Validate the header data structure of a Half-Life 1 MDL file.
+     * \param[in] header Input header to be validated.
+     * \param[in] is_texture_header Whether or not we are reading an MDL
+     *   texture file.
+     */
+    void validate_header(const Header_HL1 *header, bool is_texture_header);
+
+    void load_texture_file();
+    void load_sequence_groups_files();
+    void read_textures();
+    void read_skins();
+    void read_bones();
+    void read_meshes();
+    void read_animations();
+    void read_sequence_groups_info();
+    void read_sequence_infos();
+    void read_sequence_transitions();
+    void read_attachments();
+    void read_hitboxes();
+    void read_bone_controllers();
+    void read_global_info();
+
+private:
+    void release_resources();
+
+    /** \brief Load a file and copy it's content to a buffer.
+     * \param file_path The path to the file to be loaded.
+     * \param buffer A pointer to a buffer to receive the data.
+     */
+    template <typename MDLFileHeader>
+    void load_file_into_buffer(const std::string &file_path, unsigned char *&buffer);
+
+    /** \brief Read an MDL texture.
+     * \param[in] ptexture A pointer to an MDL texture.
+     * \param[in] data A pointer to the data from \p ptexture.
+     * \param[in] pal A pointer to the texture palette from \p ptexture.
+     * \param[in,out] pResult A pointer to the output resulting Assimp texture.
+     * \param[in,out] last_palette_color The last color from the image palette.
+     */
+    void read_texture(const Texture_HL1 *ptexture,
+            uint8_t *data, uint8_t *pal, aiTexture *pResult,
+            aiColor3D &last_palette_color);
+
+    /** \brief This method reads a compressed anim value.
+    * \param[in] panimvalue A pointer to the animation data.
+    * \param[in] frame The frame to look for.
+    * \param[in] bone_scale The current bone scale to apply to the compressed value.
+    * \param[in,out] value The decompressed anim value at \p frame.
+    */
+    void extract_anim_value(const AnimValue_HL1 *panimvalue,
+            int frame, float bone_scale, float &value);
+
+    /**
+     *  \brief Given the number of blend animations, determine the number of blend controllers.
+     *
+     * \param[in] num_blend_animations The number of blend animations.
+     * \param[out] num_blend_controllers The number of blend controllers.
+     * \return True if the number of blend controllers was determined. False otherwise.
+     */
+    static bool get_num_blend_controllers(const int num_blend_animations, int &num_blend_controllers);
+
+    /** Output scene to be filled */
+    aiScene *scene_;
+
+    /** Output I/O handler. Required for additional IO operations. */
+    IOSystem *io_;
+
+    /** Buffer from MDLLoader class. */
+    const unsigned char *buffer_;
+
+    /** The full file path to the MDL file we are trying to load.
+     * Used to locate other MDL files since MDL may store resources
+     * in external MDL files. */
+    const std::string &file_path_;
+
+    /** Configuration for HL1 MDL */
+    const HL1ImportSettings &import_settings_;
+
+    /** Main MDL header. */
+    const Header_HL1 *header_;
+
+    /** External MDL texture header. */
+    const Header_HL1 *texture_header_;
+
+    /** External MDL animation headers.
+     * One for each loaded animation file. */
+    SequenceHeader_HL1 **anim_headers_;
+
+    /** Texture file data. */
+    unsigned char *texture_buffer_;
+
+    /** Animation files data. */
+    unsigned char **anim_buffers_;
+
+    /** The number of sequence groups. */
+    int num_sequence_groups_;
+
+    /** The list of children to be appended to the scene's root node. */
+    std::vector<aiNode *> rootnode_children_;
+
+    /** A unique name generator. Used to generate names for MDL values
+     * that may have empty/duplicate names. */
+    UniqueNameGenerator unique_name_generator_;
+
+    /** The list of unique sequence names. */
+    std::vector<std::string> unique_sequence_names_;
+
+    /** The list of unique sequence groups names. */
+    std::vector<std::string> unique_sequence_groups_names_;
+
+    /** Structure to store temporary bone information. */
+    struct TempBone {
+
+        TempBone() :
+            node(nullptr),
+            absolute_transform(),
+            offset_matrix() {}
+
+        aiNode *node;
+        aiMatrix4x4 absolute_transform;
+        aiMatrix4x4 offset_matrix;
+    };
+
+    std::vector<TempBone> temp_bones_;
+
+    /** The number of available bone controllers in the model. */
+    int num_blend_controllers_;
+
+    /** Self explanatory. */
+    int total_models_;
+};
+
+// ------------------------------------------------------------------------------------------------
+template <typename MDLFileHeader>
+void HL1MDLLoader::load_file_into_buffer(const std::string &file_path, unsigned char *&buffer) {
+    if (!io_->Exists(file_path))
+        throw DeadlyImportError("Missing file " + DefaultIOSystem::fileName(file_path) + ".");
+
+    std::unique_ptr<IOStream> file(io_->Open(file_path));
+
+    if (file.get() == NULL)
+        throw DeadlyImportError("Failed to open MDL file " + DefaultIOSystem::fileName(file_path) + ".");
+
+    const size_t file_size = file->FileSize();
+    if (file_size < sizeof(MDLFileHeader))
+        throw DeadlyImportError("MDL file is too small.");
+
+    buffer = new unsigned char[1 + file_size];
+    file->Read((void *)buffer, 1, file_size);
+    buffer[file_size] = '\0';
+}
+
+} // namespace HalfLife
+} // namespace MDL
+} // namespace Assimp
+
+#endif // AI_HL1MDLLOADER_INCLUDED

code/MDL/HalfLife/HL1MeshTrivert.h

@@ -0,0 +1,127 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file HL1MeshTrivert.h
+ *  @brief This file contains the class declaration for the
+ *         HL1 mesh trivert class.
+ */
+
+#ifndef AI_HL1MESHTRIVERT_INCLUDED
+#define AI_HL1MESHTRIVERT_INCLUDED
+
+#include "HL1FileData.h"
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+/* A class to help map model triverts to mesh triverts. */
+struct HL1MeshTrivert {
+    HL1MeshTrivert() :
+        vertindex(-1),
+        normindex(-1),
+        s(0),
+        t(0),
+        localindex(-1) {
+    }
+
+    HL1MeshTrivert(short vertindex, short normindex, short s, short t, short localindex) :
+        vertindex(vertindex),
+        normindex(normindex),
+        s(s),
+        t(t),
+        localindex() {
+    }
+
+    HL1MeshTrivert(const Trivert &a) :
+        vertindex(a.vertindex),
+        normindex(a.normindex),
+        s(a.s),
+        t(a.t),
+        localindex(-1) {
+    }
+
+    inline bool operator==(const Trivert &a) const {
+        return vertindex == a.vertindex &&
+               normindex == a.normindex &&
+               s == a.s &&
+               t == a.t;
+    }
+
+    inline bool operator!=(const Trivert &a) const {
+        return !(*this == a);
+    }
+
+    inline bool operator==(const HL1MeshTrivert &a) const {
+        return localindex == a.localindex &&
+               vertindex == a.vertindex &&
+               normindex == a.normindex &&
+               s == a.s &&
+               t == a.t;
+    }
+
+    inline bool operator!=(const HL1MeshTrivert &a) const {
+        return !(*this == a);
+    }
+
+    inline HL1MeshTrivert &operator=(const Trivert &other) {
+        vertindex = other.vertindex;
+        normindex = other.normindex;
+        s = other.s;
+        t = other.t;
+        return *this;
+    }
+
+    short vertindex;
+    short normindex;
+    short s, t;
+    short localindex;
+};
+
+struct HL1MeshFace {
+    short v0, v1, v2;
+};
+
+} // namespace HalfLife
+} // namespace MDL
+} // namespace Assimp
+
+#endif // AI_HL1MESHTRIVERT_INCLUDED

code/MDL/HalfLife/HalfLifeMDLBaseHeader.h

@@ -0,0 +1,64 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file HalfLifeMDLBaseHeader.h */
+
+#ifndef AI_HALFLIFEMDLBASEHEADER_INCLUDED
+#define AI_HALFLIFEMDLBASEHEADER_INCLUDED
+
+#include <assimp/types.h>
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+/** Used to interface different Valve MDL formats. */
+struct HalfLifeMDLBaseHeader
+{
+    char ident[4];
+    int32_t version;
+};
+
+}
+}
+}
+
+#endif // AI_HALFLIFEMDLBASEHEADER_INCLUDED

code/MDL/HalfLife/LogFunctions.h

@@ -0,0 +1,95 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file LogFunctions.h */
+
+#ifndef AI_MDL_HALFLIFE_LOGFUNCTIONS_INCLUDED
+#define AI_MDL_HALFLIFE_LOGFUNCTIONS_INCLUDED
+
+#include <assimp/Logger.hpp>
+#include <string>
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+/**
+ * \brief A function to log precise messages regarding limits exceeded.
+ *
+ * \param[in] subject Subject.
+ * \param[in] current_amount Current amount.
+ * \param[in] direct_object Direct object.
+ *            LIMIT Limit constant.
+ *
+ * Example: Model has 100 textures, which exceeds the limit (50)
+ *
+ *          where \p subject is 'Model'
+ *                \p current_amount is '100'
+ *                \p direct_object is 'textures'
+ *                LIMIT is '50'
+ */
+template <int LIMIT>
+static inline void log_warning_limit_exceeded(
+    const std::string &subject, int current_amount,
+    const std::string &direct_object) {
+
+    ASSIMP_LOG_WARN(MDL_HALFLIFE_LOG_HEADER
+        + subject
+        + " has "
+        + std::to_string(current_amount) + " "
+        + direct_object
+        + ", which exceeds the limit ("
+        + std::to_string(LIMIT)
+        + ")");
+}
+
+/** \brief Same as above, but uses 'Model' as the subject. */
+template <int LIMIT>
+static inline void log_warning_limit_exceeded(int current_amount,
+    const std::string &direct_object) {
+    log_warning_limit_exceeded<LIMIT>("Model", current_amount, direct_object);
+}
+
+} // namespace HalfLife
+} // namespace MDL
+} // namespace Assimp
+
+#endif // AI_MDL_HALFLIFE_LOGFUNCTIONS_INCLUDED

code/MDL/HalfLife/UniqueNameGenerator.cpp

@@ -0,0 +1,180 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file UniqueNameGenerator.cpp
+ *  @brief Implementation for the unique name generator.
+ */
+
+#include "UniqueNameGenerator.h"
+#include <algorithm>
+#include <list>
+#include <map>
+#include <numeric>
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+UniqueNameGenerator::UniqueNameGenerator() :
+    template_name_("unnamed"),
+    separator_("_") {
+}
+
+UniqueNameGenerator::UniqueNameGenerator(const char *template_name) :
+    template_name_(template_name),
+    separator_("_") {
+}
+
+UniqueNameGenerator::UniqueNameGenerator(const char *template_name, const char *separator) :
+    template_name_(template_name),
+    separator_(separator) {
+}
+
+UniqueNameGenerator::~UniqueNameGenerator() {
+}
+
+void UniqueNameGenerator::make_unique(std::vector<std::string> &names) {
+    struct DuplicateInfo {
+        DuplicateInfo() :
+            indices(),
+            next_id(0) {
+        }
+
+        std::list<size_t> indices;
+        size_t next_id;
+    };
+
+    std::vector<size_t> empty_names_indices;
+    std::vector<size_t> template_name_duplicates;
+    std::map<std::string, DuplicateInfo> names_to_duplicates;
+
+    const std::string template_name_with_separator(template_name_ + separator_);
+
+    auto format_name = [&](const std::string &base_name, size_t id) -> std::string {
+        return base_name + separator_ + std::to_string(id);
+    };
+
+    auto generate_unique_name = [&](const std::string &base_name) -> std::string {
+        auto *duplicate_info = &names_to_duplicates[base_name];
+
+        std::string new_name = "";
+
+        bool found_identical_name;
+        bool tried_with_base_name_only = false;
+        do {
+            // Assume that no identical name exists.
+            found_identical_name = false;
+
+            if (!tried_with_base_name_only) {
+                // First try with only the base name.
+                new_name = base_name;
+            } else {
+                // Create the name expected to be unique.
+                new_name = format_name(base_name, duplicate_info->next_id);
+            }
+
+            // Check in the list of duplicates for an identical name.
+            for (size_t i = 0;
+                    i < names.size() &&
+                    !found_identical_name;
+                    ++i) {
+                if (new_name == names[i])
+                    found_identical_name = true;
+            }
+
+            if (tried_with_base_name_only)
+                ++duplicate_info->next_id;
+
+            tried_with_base_name_only = true;
+
+        } while (found_identical_name);
+
+        return new_name;
+    };
+
+    for (size_t i = 0; i < names.size(); ++i) {
+        // Check for empty names.
+        if (names[i].find_first_not_of(' ') == std::string::npos) {
+            empty_names_indices.push_back(i);
+            continue;
+        }
+
+        /* Check for potential duplicate.
+        a) Either if this name is the same as the template name or
+        b) <template name><separator> is found at the beginning. */
+        if (names[i] == template_name_ ||
+                names[i].substr(0, template_name_with_separator.length()) == template_name_with_separator)
+            template_name_duplicates.push_back(i);
+
+        // Map each unique name to it's duplicate.
+        if (names_to_duplicates.count(names[i]) == 0)
+            names_to_duplicates.insert_or_assign(names[i], DuplicateInfo());
+        else
+            names_to_duplicates[names[i]].indices.push_back(i);
+    }
+
+    // Make every non-empty name unique.
+    for (auto it = names_to_duplicates.begin();
+            it != names_to_duplicates.end(); ++it) {
+        for (auto it2 = it->second.indices.begin();
+                it2 != it->second.indices.end();
+                ++it2)
+            names[*it2] = generate_unique_name(it->first);
+    }
+
+    // Generate a unique name for every empty string.
+    if (template_name_duplicates.size()) {
+        // At least one string ressembles to <template name>.
+        for (auto it = empty_names_indices.begin();
+                it != empty_names_indices.end(); ++it)
+            names[*it] = generate_unique_name(template_name_);
+    } else {
+        // No string alike <template name> exists.
+        size_t i = 0;
+        for (auto it = empty_names_indices.begin();
+                it != empty_names_indices.end(); ++it, ++i)
+            names[*it] = format_name(template_name_, i);
+    }
+}
+
+} // namespace HalfLife
+} // namespace MDL
+} // namespace Assimp

code/MDL/HalfLife/UniqueNameGenerator.h

@@ -0,0 +1,81 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file UniqueNameGenerator.h
+ *  @brief Declaration of the unique name generator.
+ */
+
+#ifndef AI_UNIQUENAMEGENERATOR_INCLUDED
+#define AI_UNIQUENAMEGENERATOR_INCLUDED
+
+#include <string>
+#include <vector>
+
+namespace Assimp {
+namespace MDL {
+namespace HalfLife {
+
+class UniqueNameGenerator {
+public:
+    UniqueNameGenerator();
+    UniqueNameGenerator(const char *template_name);
+    UniqueNameGenerator(const char *template_name, const char *separator);
+    ~UniqueNameGenerator();
+
+    inline void set_template_name(const char *template_name) {
+        template_name_ = template_name;
+    }
+    inline void set_separator(const char *separator) {
+        separator_ = separator;
+    }
+
+    void make_unique(std::vector<std::string> &names);
+
+private:
+    std::string template_name_;
+    std::string separator_;
+};
+
+} // namespace HalfLife
+} // namespace MDL
+} // namespace Assimp
+
+#endif // AI_UNIQUENAMEGENERATOR_INCLUDED

code/MDL/MDLLoader.cpp

@@ -51,6 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "MDL/MDLLoader.h"
 #include "MDL/MDLDefaultColorMap.h"
 #include "MD2/MD2FileData.h"
+#include "MDL/HalfLife/HL1MDLLoader.h"
 
 #include <assimp/qnan.h>
 #include <assimp/StringUtils.h>
@@ -142,6 +143,18 @@ void MDLImporter::SetupProperties(const Importer* pImp)
 
     // AI_CONFIG_IMPORT_MDL_COLORMAP - palette file
     configPalette =  pImp->GetPropertyString(AI_CONFIG_IMPORT_MDL_COLORMAP,"colormap.lmp");
+
+    // Read configuration specific to MDL (Half-Life 1).
+    mHL1ImportSettings.read_animations = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATIONS, true);
+    if (mHL1ImportSettings.read_animations) {
+        mHL1ImportSettings.read_animation_events = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATION_EVENTS, true);
+        mHL1ImportSettings.read_blend_controllers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_BLEND_CONTROLLERS, true);
+        mHL1ImportSettings.read_sequence_transitions = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_SEQUENCE_TRANSITIONS, true);
+    }
+    mHL1ImportSettings.read_attachments = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_ATTACHMENTS, true);
+    mHL1ImportSettings.read_bone_controllers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_BONE_CONTROLLERS, true);
+    mHL1ImportSettings.read_hitboxes = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_HITBOXES, true);
+    mHL1ImportSettings.read_misc_global_info = pImp->GetPropertyBool(AI_CONFIG_IMPORT_MDL_HL1_READ_MISC_GLOBAL_INFO, true);
 }
 
 // ------------------------------------------------------------------------------------------------
@@ -224,10 +237,20 @@ void MDLImporter::InternReadFile( const std::string& pFile,
     else if (AI_MDL_MAGIC_NUMBER_BE_HL2a == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_HL2a == iMagicWord ||
         AI_MDL_MAGIC_NUMBER_BE_HL2b == iMagicWord || AI_MDL_MAGIC_NUMBER_LE_HL2b == iMagicWord)
     {
-        ASSIMP_LOG_DEBUG("MDL subtype: Source(tm) Engine, magic word is IDST/IDSQ");
         iGSFileVersion = 0;
+
+        HalfLife::HalfLifeMDLBaseHeader *pHeader = (HalfLife::HalfLifeMDLBaseHeader *)mBuffer;
+        if (pHeader->version == AI_MDL_HL1_VERSION)
+        {
+            ASSIMP_LOG_DEBUG("MDL subtype: Half-Life 1/Goldsrc Engine, magic word is IDST/IDSQ");
+            InternReadFile_HL1(pFile, iMagicWord);
+        }
+        else
+        {
+            ASSIMP_LOG_DEBUG("MDL subtype: Source(tm) Engine, magic word is IDST/IDSQ");
             InternReadFile_HL2();
         }
+    }
     else    {
         // print the magic word to the log file
         throw DeadlyImportError( "Unknown MDL subformat " + pFile +
@@ -1955,6 +1978,23 @@ void MDLImporter::JoinSkins_3DGS_MDL7(
     }
 }
 
+// ------------------------------------------------------------------------------------------------
+// Read a Half-life 1 MDL
+void MDLImporter::InternReadFile_HL1(const std::string& pFile, const uint32_t iMagicWord)
+{
+    // We can't correctly load an MDL from a MDL "sequence" file.
+    if (iMagicWord == AI_MDL_MAGIC_NUMBER_BE_HL2b || iMagicWord == AI_MDL_MAGIC_NUMBER_LE_HL2b)
+        throw DeadlyImportError("Impossible to properly load a model from an MDL sequence file.");
+
+    // Read the MDL file.
+    HalfLife::HL1MDLLoader loader(
+        pScene,
+        pIOHandler,
+        mBuffer,
+        pFile,
+        mHL1ImportSettings);
+}
+
 // ------------------------------------------------------------------------------------------------
 // Read a half-life 2 MDL
 void MDLImporter::InternReadFile_HL2( )

code/MDL/MDLLoader.h

@@ -51,6 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/BaseImporter.h>
 #include "MDLFileData.h"
 #include "HMP/HalfLifeFileData.h"
+#include "HalfLife/HL1ImportSettings.h"
 
 struct aiNode;
 struct aiTexture;
@@ -77,6 +78,7 @@ using namespace MDL;
  *      <li>3D Game Studio MDL3, MDL4</li>
  *      <li>3D Game Studio MDL5</li>
  *      <li>3D Game Studio MDL7</li>
+ *      <li>Halflife 1</li>
  *      <li>Halflife 2</li>
  *   </ul>
  *  These formats are partially identical and it would be possible to load
@@ -131,6 +133,11 @@ protected:
     */
     void InternReadFile_3DGS_MDL7( );
 
+    // -------------------------------------------------------------------
+    /** Import a Half-Life 1 MDL file
+    */
+    void InternReadFile_HL1(const std::string& pFile, const uint32_t iMagicWord);
+
     // -------------------------------------------------------------------
     /** Import a CS:S/HL2 MDL file (not fully implemented)
     */
@@ -436,6 +443,9 @@ protected:
 
     /** Size of the input file in bytes */
     unsigned int iFileSize;
+
+    /* Configuration for HL1 MDL */
+    HalfLife::HL1ImportSettings mHL1ImportSettings;
 };
 
 } // end of namespace Assimp

include/assimp/config.h.in

@@ -695,6 +695,73 @@ enum aiComponent
 #define AI_CONFIG_IMPORT_SMD_KEYFRAME       "IMPORT_SMD_KEYFRAME"
 #define AI_CONFIG_IMPORT_UNREAL_KEYFRAME    "IMPORT_UNREAL_KEYFRAME"
 
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read animations.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATIONS "IMPORT_MDL_HL1_READ_ANIMATIONS"
+
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read animation events.
+ * \note This property requires AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATIONS to be set to true.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATION_EVENTS "IMPORT_MDL_HL1_READ_ANIMATION_EVENTS"
+
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read blend controllers.
+ * \note This property requires AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATIONS to be set to true.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_BLEND_CONTROLLERS "IMPORT_MDL_HL1_READ_BLEND_CONTROLLERS"
+
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read sequence transition graph.
+ * \note This property requires AI_CONFIG_IMPORT_MDL_HL1_READ_ANIMATIONS to be set to true.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_SEQUENCE_TRANSITIONS "IMPORT_MDL_HL1_READ_SEQUENCE_TRANSITIONS"
+
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read attachments info.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_ATTACHMENTS "IMPORT_MDL_HL1_READ_ATTACHMENTS"
+
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read bone controllers info.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_BONE_CONTROLLERS "IMPORT_MDL_HL1_READ_BONE_CONTROLLERS"
+
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read hitboxes info.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_HITBOXES "IMPORT_MDL_HL1_READ_HITBOXES"
+
+// ---------------------------------------------------------------------------
+/** @brief Set whether the MDL (HL1) importer will read miscellaneous global model info.
+ *
+ * The default value is true (1)
+ * Property type: bool
+ */
+#define AI_CONFIG_IMPORT_MDL_HL1_READ_MISC_GLOBAL_INFO "IMPORT_MDL_HL1_READ_MISC_GLOBAL_INFO"
+
 // ---------------------------------------------------------------------------
 /** Smd load multiple animations
  *