assimp/include/aiPostProcess.h

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/** @file aiPostProcess.h
 *  @brief Definitions for import post processing steps
 */
#ifndef AI_POSTPROCESS_H_INC
#define AI_POSTPROCESS_H_INC

#include "aiTypes.h"

#ifdef __cplusplus
extern "C" {
#endif

// -----------------------------------------------------------------------------------
/** @enum  aiPostProcessSteps
 *  @brief Defines the flags for all possible post processing steps.
 *
 *  @see Importer::ReadFile
 *  @see aiImportFile
 *  @see aiImportFileEx
 */
// -----------------------------------------------------------------------------------
enum aiPostProcessSteps
{

	// -------------------------------------------------------------------------
	/** <hr>Calculates the tangents and bitangents for the imported meshes. 
	 *
	 * Does nothing if a mesh does not have normals. You might want this post 
	 * processing step to be executed if you plan to use tangent space calculations 
	 * such as normal mapping  applied to the meshes. There's a config setting,
	 * <tt>#AI_CONFIG_PP_CT_MAX_SMOOTHING_ANGLE</tt>, which allows you to specify
	 * a maximum smoothing angle for the algorithm. However, usually you'll
	 * want to let the default value. Thanks.
	 */
	aiProcess_CalcTangentSpace = 0x1,

	// -------------------------------------------------------------------------
	/** <hr>Identifies and joins identical vertex data sets within all 
	 *  imported meshes. 
	 * 
	 * After this step is run each mesh does contain only unique vertices anymore,
	 * so a vertex is possibly used by multiple faces. You usually want
	 * to use this post processing step. If your application deals with
	 * indexed geometry, this step is compulsory or you'll just waste rendering
	 * time. <b>If this flag is not specified</b>, no vertices are referenced by
	 * more than one face and <b>no index buffer is required</b> for rendering.
	 */
	aiProcess_JoinIdenticalVertices = 0x2,

	// -------------------------------------------------------------------------
	/** <hr>Converts all the imported data to a left-handed coordinate space. 
	 *
	 * By default the data is returned in a right-handed coordinate space which 
	 * for example OpenGL prefers. In this space, +X points to the right, 
	 * +Z points towards the viewer and and +Y points upwards. In the DirectX 
     * coordinate space +X points to the right, +Y points upwards and +Z points 
     * away from the viewer.
	 *
	 * You'll probably want to consider this flag if you use Direct3D for
	 * rendering. The #aiProcess_ConvertToLeftHanded flag supersedes this
	 * setting and boundles all conversions typically required for D3D-based
	 * applications.
	 */
	aiProcess_MakeLeftHanded = 0x4,

	// -------------------------------------------------------------------------
	/** <hr>Triangulates all faces of all meshes. 
	 *
	 * By default the imported mesh data might contain faces with more than 3
	 * indices. For rendering you'll usually want all faces to be triangles. 
	 * This post processing step splits up all higher faces to triangles. 
	 * Line and point primitives are *not* modified!. If you want
	 * 'triangles only' with no other kinds of primitives, try the following
	 * solution:
	 * <ul>
	 * <li>Specify both #aiProcess_Triangulate and #aiProcess_SortByPType </li>
	 * </li>Ignore all point and line meshes when you process assimp's output</li>
	 * </ul>
	 */
	aiProcess_Triangulate = 0x8,

	// -------------------------------------------------------------------------
	/** <hr>Removes some parts of the data structure (animations, materials, 
	 *  light sources, cameras, textures, vertex components).
	 *
	 * The  components to be removed are specified in a separate
	 * configuration option, <tt>#AI_CONFIG_PP_RVC_FLAGS</tt>. This is quite useful
	 * if you don't need all parts of the output structure. Especially vertex 
	 * colors are rarely used today ... . Calling this step to remove unrequired
	 * stuff from the pipeline as early as possible results in an increased 
	 * performance and a better optimized output data structure.
	 * This step is also useful if you want to force Assimp to recompute 
	 * normals or tangents. The corresponding steps don't recompute them if 
	 * they're already there (loaded from the source asset). By using this 
	 * step you can make sure they are NOT there.
	 *
	 * This flag is a poor one, mainly because it's purpose is usually
     * misunderstood. Consider the following case: a 3d model has been exported
	 * from a CAD app, it has per-face vertex colors. Vertex positions can't be
	 * shared, thus the #aiProcess_JoinIdenticalVertices step fails to
	 * optimize the data. Just because these nasty, little vertex colors.
	 * Most apps don't even process them, so it's all for nothing. By using
	 * this step, unneeded components are excluded as early as possible
	 * thus opening more room for internal optimzations. 
	 */
	aiProcess_RemoveComponent = 0x10,

	// -------------------------------------------------------------------------
	/** <hr>Generates normals for all faces of all meshes. 
	 *
	 * This is ignored if normals are already there at the time where this flag 
	 * is evaluated. Model importers try to load them from the source file, so
	 * they're usually already there. Face normals are shared between all points
	 * of a single face, so a single point can have multiple normals, which in
	 * other words, enforces the library to duplicate vertices in some cases.
	 * #aiProcess_JoinIdenticalVertices is *senseless* then.
	 *
	 * This flag may not be specified together with #aiProcess_GenSmoothNormals.
	 */
	aiProcess_GenNormals = 0x20,

	// -------------------------------------------------------------------------
	/** <hr>Generates smooth normals for all vertices in the mesh.
	*
	* This is ignored if normals are already there at the time where this flag 
	* is evaluated. Model importers try to load them from the source file, so
	* they're usually already there. 
	*
	* This flag may (of course) not be specified together with 
	* #aiProcess_GenNormals. There's a configuration option, 
	* <tt>#AI_CONFIG_PP_GSN_MAX_SMOOTHING_ANGLE</tt> which allows you to specify
	* an angle maximum for the normal smoothing algorithm. Normals exceeding
	* this limit are not smoothed, resulting in a a 'hard' seam between two faces.
	* Using a decent angle here (e.g. 80<EFBFBD>) results in very good visual
	* appearance.
	*/
	aiProcess_GenSmoothNormals = 0x40,

	// -------------------------------------------------------------------------
	/** <hr>Splits large meshes into smaller submeshes
	*
	* This is quite useful for realtime rendering where the number of triangles
	* which can be maximally processed in a single draw-call is usually limited 
	* by the video driver/hardware. The maximum vertex buffer is usually limited,
	* too. Both requirements can be met with this step: you may specify both a 
	* triangle and vertex limit for a single mesh.
	*
	* The split limits can (and should!) be set through the 
	* <tt>#AI_CONFIG_PP_SLM_VERTEX_LIMIT</tt> and <tt>#AI_CONFIG_PP_SLM_TRIANGLE_LIMIT</tt> 
	* settings. The default values are <tt>#AI_SLM_DEFAULT_MAX_VERTICES</tt> and 
	* <tt>#AI_SLM_DEFAULT_MAX_TRIANGLES</tt>. 
	*
	* Note that splitting is generally a time-consuming task, but not if there's
	* nothing to split. The use of this step is recommended for most users.
	*/
	aiProcess_SplitLargeMeshes = 0x80,

	// -------------------------------------------------------------------------
	/** <hr>Removes the node graph and pre-transforms all vertices with
	* the local transformation matrices of their nodes. The output
	* scene does still contain nodes, however, there is only a
	* root node with children, each one referencing only one mesh,
	* each mesh referencing one material. For rendering, you can
	* simply render all meshes in order, you don't need to pay
	* attention to local transformations and the node hierarchy.
	* Animations are removed during this step. 
	* This step is intended for applications that have no scenegraph.
	* The step CAN cause some problems: if e.g. a mesh of the asset
	* contains normals and another, using the same material index, does not, 
	* they will be brought together, but the first meshes's part of
	* the normal list will be zeroed.
	*/
	aiProcess_PreTransformVertices = 0x100,

	// -------------------------------------------------------------------------
	/** <hr>Limits the number of bones simultaneously affecting a single vertex
	*  to a maximum value.
	*
	* If any vertex is affected by more than that number of bones, the least 
	* important vertex weights are removed and the remaining vertex weights are
	* renormalized so that the weights still sum up to 1.
	* The default bone weight limit is 4 (defined as <tt>#AI_LMW_MAX_WEIGHTS</tt> in
	* aiConfig.h), but you can use the <tt>#AI_CONFIG_PP_LBW_MAX_WEIGHTS</tt> setting to
	* supply your own limit to the post processing step.
	*
	* If you intend to perform the skinning in hardware, this post processing 
	* step might be of interest for you.
	*/
	aiProcess_LimitBoneWeights = 0x200,

	// -------------------------------------------------------------------------
	/** <hr>Validates the imported scene data structure
	 * This makes sure that all indices are valid, all animations and
	 * bones are linked correctly, all material references are correct .. etc.
	 *
	 * It is recommended to capture Assimp's log output if you use this flag,
	 * so you can easily find ot what's actually wrong if a file fails the
	 * validation. The validator is quite rude and will find *all*
	 * inconsistencies in the data structure ... plugin developers are
	 * recommended to use it to debug their loaders. There are two types of
	 * validation failures:
	 * <ul>
	 * <li>Error: There's something wrong with the imported data. Further
	 *   postprocessing is not possible and the data is not usable at all.
	 *   The import fails. #Importer::GetErrorString() or #aiGetErrorString()
	 *   carry the error message around.</li>
	 * <li>Warning: There are some minor issues (e.g. 1000000 animation 
	 *   keyframes with the same time), but further postprocessing and use
	 *   of the data structure is still safe. Warning details are written
	 *   to the log file, <tt>#AI_SCENE_FLAGS_VALIDATION_WARNING</tt> is set
	 *   in #aiScene::mFlags</li>
	 * </ul>
	 *
	 * This post-processing step is not time-consuming. It's use is not
	 * compulsory, but recommended. 
	*/
	aiProcess_ValidateDataStructure = 0x400,

	// -------------------------------------------------------------------------
	/** <hr>Reorders triangles for better vertex cache locality.
	 *
	 * The step tries to improve the ACMR (average post-transform vertex cache
	 * miss ratio) for all meshes. The implementation runs in O(n) and is 
	 * roughly based on the 'tipsify' algorithm (see <a href="
	 * http://www.cs.princeton.edu/gfx/pubs/Sander_2007_%3ETR/tipsy.pdf">this
	 * paper</a>).
	 *
	 * If you intend to render huge models in hardware, this step might
	 * be of interest for you. The <tt>#AI_CONFIG_PP_ICL_PTCACHE_SIZE</tt>config
	 * setting can be used to fine-tune the cache optimization.
	 */
	aiProcess_ImproveCacheLocality = 0x800,

	// -------------------------------------------------------------------------
	/** <hr>Searches for redundant/unreferenced materials and removes them.
	 *
	 * This is especially useful in combination with the 
	 * #aiProcess_PretransformVertices and #aiProcess_OptimizeMeshes flags. 
	 * Both join small meshes with equal characteristics, but they can't do 
	 * their work if two meshes have different materials. Because several
	 * material settings are always lost during Assimp's import filters,
	 * (and because many exporters don't check for redundant materials), huge
	 * models often have materials which are are defined several times with
	 * exactly the same settings ..
	 *
	 * Several material settings not contributing to the final appearance of
	 * a surface are ignored in all comparisons ... the material name is
	 * one of them. So, if you're passing additional information through the
	 * content pipeline (probably using using *magic* material names), don't 
	 * specify this flag. Alternatively take a look at the
	 * <tt>#AI_CONFIG_PP_RRM_EXCLUDE_LIST</tt> setting.
	 */ 
	aiProcess_RemoveRedundantMaterials = 0x1000,

	// -------------------------------------------------------------------------
	/** <hr>This step tries to determine which meshes have normal vectors 
	 * that are facing inwards. The algorithm is simple but effective:
	 * the bounding box of all vertices + their normals is compared against
	 * the volume of the bounding box of all vertices without their normals.
	 * This works well for most objects, problems might occur with planar
	 * surfaces. However, the step tries to filter such cases.
	 * The step inverts all in-facing normals. Generally it is recommended
	 * to enable this step, although the result is not always correct.
	*/
	aiProcess_FixInfacingNormals = 0x2000,

	// -------------------------------------------------------------------------
	/** <hr>This step splits meshes with more than one primitive type in 
	 *  homogeneous submeshes. 
	 *
	 *  The step is executed after the triangulation step. After the step
	 *  returns, just one bit is set in aiMesh::mPrimitiveTypes. This is 
	 *  especially useful for real-time rendering where point and line
	 *  primitives are often ignored or rendered separately.
	 *  You can use the <tt>#AI_CONFIG_PP_SBP_REMOVE</tt> option to specify which
	 *  primitive types you need. This can be used to easily exclude
	 *  lines and points, which are rarely used, from the import.
	*/
	aiProcess_SortByPType = 0x8000,

	// -------------------------------------------------------------------------
	/** <hr>This step searches all meshes for degenerated primitives and
	 *  converts them to proper lines or points.
	 *
	 * A face is 'degenerated' if one or more of its points are identical.
	 * To have the degenerated stuff not only detected and collapsed but
	 * also removed, try one of the following procedures:
	 * <br><b>1.</b> (if you support lines&points for rendering but don't
	 *    want the degenerates)</br>
	 * <ul>
	 *   <li>Specify the #aiProcess_FindDegenerates flag.
	 *   </li>
	 *   <li>Set the <tt>AI_CONFIG_PP_FD_REMOVE</tt> option to 1. This will 
	 *       cause the step to remove degenerated triangles from the import
	 *       as soon as they're detected. They won't pass any further
	 *       pipeline steps.
	 *   </li>
	 * </ul>
	 * <br><b>2.</b>(if you don't support lines&points at all ...)</br>
	 * <ul>
	 *   <li>Specify the #aiProcess_FindDegenerates flag.
	 *   </li>
	 *   <li>Specify the #aiProcess_SortByPType flag. This moves line and
	 *     point primitives to separate meshes.
	 *   </li>
	 *   <li>Set the <tt>AI_CONFIG_PP_SBP_REMOVE</tt> option to 
	 *       @code aiPrimitiveType_POINTS | aiPrimitiveType_LINES
	 *       @endcode to cause SortByPType to reject point
	 *       and line meshes from the scene.
	 *   </li>
	 * </ul>
	 * @note Degenerated polygons are not necessarily evil and that's why
	 * they're not removed by default. There are several file formats which 
	 * don't support lines or points ... some exporters bypass the
	 * format specification and write them as degenerated triangle instead.
	*/
	aiProcess_FindDegenerates = 0x10000,

	// -------------------------------------------------------------------------
	/** <hr>This step searches all meshes for invalid data, such as zeroed
	 *  normal vectors or invalid UV coords and removes them.
	 *
	 * This is especially useful for normals. If they are invalid, and
	 * the step recognizes this, they will be removed and can later
	 * be computed by one of the other steps.<br>
	 * The step will also remove meshes that are infinitely small.
	*/
	aiProcess_FindInvalidData = 0x20000,

	// -------------------------------------------------------------------------
	/** <hr>This step converts non-UV mappings (such as spherical or
	 *  cylindrical apping) to proper texture coordinate channels.
	 *
	 * Most applications will support UV mapping only, so you will
	 * probably want to specify this step in every case. Note tha Assimp is not
	 * always able to match the original mapping implementation of the 
	 * 3d app which produced a model perfectly. It's always better to let the
	 * father app compute the UV channels, at least 3ds max, maja, blender, 
	 * lightwave, modo, ... are able to achieve this.
	 *
	 * @note If this step is not requested, you'll need to process the
	 * <tt>#AI_MATKEY_MAPPING<7tt> material property in order to display all assets
	 * properly.
	 */
	aiProcess_GenUVCoords = 0x40000,

	// -------------------------------------------------------------------------
	/** <hr>This step applies per-texture UV transformations and bakes
	 *  them to stand-alone vtexture coordinate channelss.
	 *  
	 * UV transformations are specified per-texture - see the 
	 * <tt>#AI_MATKEY_UVTRANSFORM</tt> material key for more information. 
	 * This step processes all textures with 
	 * transformed input UV coordinates and generates new (pretransformed) UV channel 
	 * which replace the old channel. Most applications won't support UV 
	 * transformations, so you will probably want to specify this step.
     *
	 * @note UV transformations are usually implemented in realtime apps by 
	 * transforming texture coordinates at vertex shader stage with a 3x3
	 * (homogenous) transformation matrix.
	*/
	aiProcess_TransformUVCoords = 0x80000,

	// -------------------------------------------------------------------------
	/** <hr>This step searches for duplicate meshes and replaces duplicates
	 *  with references to the first mesh.
	 *
	 *  This step takes a while, don't use it if you have no time.
	 *  It's main purpose is to workaround the limitation that many export
	 *  file formats don't support instanced meshes, so exporters need to
	 *  duplicate meshes. This step removes the duplicates again. Please 
 	 *  note that Assimp does currently not support per-node material
	 *  assignment to meshes, which means that identical meshes with
	 *  differnent materials are currently *not* joined, although this is 
	 *  planned for future versions.
	 */
	aiProcess_FindInstances = 0x100000,

	// -------------------------------------------------------------------------
	/** <hr>This step flips all UV coordinates along the y-axis and adjusts
	 * material settings and bitangents accordingly.
	 * <br><b>Output UV coordinate system:</b>
	 * @code
	 * 0y|0y ---------- 1x|0y 
     * |                 |
     * |                 |
     * |                 |
     * 0x|1y ---------- 1x|1y
	 * @endcode
	 *
	 * You'll probably want to consider this flag if you use Direct3D for
	 * rendering. The #aiProcess_ConvertToLeftHanded flag supersedes this
	 * setting and boundles all conversions typically required for D3D-based
	 * applications.
	*/
	aiProcess_FlipUVs = 0x80000000, /* don't change */

	// -------------------------------------------------------------------------
	/** <hr>This step adjusts the output face winding order to be cw.
	 *
	 * The default face winding order is counter clockwise.
	 * <br><b>Output face order:</b>
	 * @code
	 *       x2
	 *           
	 *                         x0
	 *  x1
	 * @endcode
	*/
	aiProcess_FlipWindingOrder  = 0x40000000 /* don't change */



	// aiProcess_GenEntityMeshes = 0x100000,
	// aiProcess_OptimizeAnimations = 0x200000
	// aiProcess_OptimizeNodes      = 0x400000
};


// ---------------------------------------------------------------------------------------
/** @def aiProcess_ConvertToLeftHanded
 *  @brief Shortcut flag for Direct3D-based applications. 
 *
 *  Supersedes the #aiProcess_MakeLeftHanded and #aiProcess_FlipUVs and
 *  The output data matches Direct3D's conventions: left-handed geometry, upper-left
 *  origin for UV coordinates and finally clockwise face order, suitable for CCW culling.
 *
 *  @deprecated 
 */
#define aiProcess_ConvertToLeftHanded ( \
	aiProcess_MakeLeftHanded     | \
	aiProcess_FlipUVs            | \
	aiProcess_FlipWindingOrder   | \
	0 ) 


// ---------------------------------------------------------------------------------------
/** @def aiProcessPreset_TargetRealtimeUse_Fast
 *  @brief Default postprocess configuration optimizing the data for real-time rendering.
 *  
 *  Applications would want to use this preset to load models on end-user PCs,
 *  maybe for direct use in game.
 *
 * If you're using DirectX, don't forget to combine this value with
 * the #aiProcess_ConvertToLeftHanded step. If you don't support UV transformations
 * in your application apply the #aiProcess_TransformUVCoords step, too.
 *  @note Please take the time to read the doc to the steps enabled by this preset. 
 *  Some of them offer further configurable properties, some of them might not be of
 *  use for you so it might be better to not specify them.
 */
#define aiProcessPreset_TargetRealtime_Fast ( \
	aiProcess_CalcTangentSpace		|  \
	aiProcess_GenNormals			|  \
	aiProcess_JoinIdenticalVertices |  \
	aiProcess_Triangulate			|  \
	aiProcess_GenUVCoords           |  \
	aiProcess_SortByPType           |  \
	0 )

 // ---------------------------------------------------------------------------------------
 /** @def aiProcessPreset_TargetRealtime_Quality
  *  @brief Default postprocess configuration optimizing the data for real-time rendering.
  *
  *  Unlike #aiProcessPreset_TargetRealtime_Fast, this configuration
  *  performs some extra optimizations to improve rendering speed and
  *  to minimize memory usage. It could be a good choice for a level editor
  *  environment where import speed is not so important.
  *  
  *  If you're using DirectX, don't forget to combine this value with
  *  the #aiProcess_ConvertToLeftHanded step. If you don't support UV transformations
  *  in your application apply the #aiProcess_TransformUVCoords step, too.
  *  @note Please take the time to read the doc for the steps enabled by this preset. 
  *  Some of them offer further configurable properties, some of them might not be of
  *  use for you so it might be better to not specify them.
  */
#define aiProcessPreset_TargetRealtime_Quality ( \
	aiProcess_CalcTangentSpace				|  \
	aiProcess_GenSmoothNormals				|  \
	aiProcess_JoinIdenticalVertices			|  \
	aiProcess_ImproveCacheLocality			|  \
	aiProcess_LimitBoneWeights				|  \
	aiProcess_RemoveRedundantMaterials      |  \
	aiProcess_SplitLargeMeshes				|  \
	aiProcess_Triangulate					|  \
	aiProcess_GenUVCoords                   |  \
	aiProcess_SortByPType                   |  \
	aiProcess_FindDegenerates               |  \
	aiProcess_FindInvalidData               |  \
	0 )

 // ---------------------------------------------------------------------------------------
 /** @def aiProcessPreset_TargetRealtime_MaxQuality
  *  @brief Default postprocess configuration optimizing the data for real-time rendering.
  *
  *  This preset enables almost every optimization step to achieve perfectly
  *  optimized data. It's your choice for level editor environments where import speed 
  *  doesn't care.
  *  
  *  If you're using DirectX, don't forget to combine this value with
  *  the #aiProcess_ConvertToLeftHanded step. If you don't support UV transformations
  *  in your application, apply the #aiProcess_TransformUVCoords step, too.
  *  @note Please take the time to read the doc for the steps enabled by this preset. 
  *  Some of them offer further configurable properties, some of them might not be of
  *  use for you so it might be better to not specify them.
  */
#define aiProcessPreset_TargetRealtime_MaxQuality ( \
	aiProcessPreset_TargetRealtime_Quality   |  \
	aiProcess_FindInstances                  |  \
	aiProcess_ValidateDataStructure          |  \
	0 )


#ifdef __cplusplus
} // end of extern "C"
#endif

#endif // AI_POSTPROCESS_H_INC