material.h File Reference

Defines the material system of the library. More...

#include <assimp/types.h>
#include "./Compiler/pushpack1.h"
#include "./Compiler/poppack1.h"

Go to the source code of this file.

Classes
struct	aiUVTransform
	Defines how an UV channel is transformed. More...
struct	aiMaterial
	Data structure for a material. More...

Macros
#define	AI_MATERIAL_H_INC
#define	AI_DEFAULT_MATERIAL_NAME   "DefaultMaterial"
#define	AI_TEXTURE_TYPE_MAX   aiTextureType_UNKNOWN
#define	AI_MATKEY_NAME   "?mat.name",0,0
#define	AI_MATKEY_TWOSIDED   "$mat.twosided",0,0
#define	AI_MATKEY_SHADING_MODEL   "$mat.shadingm",0,0
#define	AI_MATKEY_ENABLE_WIREFRAME   "$mat.wireframe",0,0
#define	AI_MATKEY_BLEND_FUNC   "$mat.blend",0,0
#define	AI_MATKEY_OPACITY   "$mat.opacity",0,0
#define	AI_MATKEY_TRANSPARENCYFACTOR   "$mat.transparencyfactor",0,0
#define	AI_MATKEY_BUMPSCALING   "$mat.bumpscaling",0,0
#define	AI_MATKEY_SHININESS   "$mat.shininess",0,0
#define	AI_MATKEY_REFLECTIVITY   "$mat.reflectivity",0,0
#define	AI_MATKEY_SHININESS_STRENGTH   "$mat.shinpercent",0,0
#define	AI_MATKEY_REFRACTI   "$mat.refracti",0,0
#define	AI_MATKEY_COLOR_DIFFUSE   "$clr.diffuse",0,0
#define	AI_MATKEY_COLOR_AMBIENT   "$clr.ambient",0,0
#define	AI_MATKEY_COLOR_SPECULAR   "$clr.specular",0,0
#define	AI_MATKEY_COLOR_EMISSIVE   "$clr.emissive",0,0
#define	AI_MATKEY_COLOR_TRANSPARENT   "$clr.transparent",0,0
#define	AI_MATKEY_COLOR_REFLECTIVE   "$clr.reflective",0,0
#define	AI_MATKEY_GLOBAL_BACKGROUND_IMAGE   "?bg.global",0,0
#define	AI_MATKEY_GLOBAL_SHADERLANG   "?sh.lang",0,0
#define	AI_MATKEY_SHADER_VERTEX   "?sh.vs",0,0
#define	AI_MATKEY_SHADER_FRAGMENT   "?sh.fs",0,0
#define	AI_MATKEY_SHADER_GEO   "?sh.gs",0,0
#define	AI_MATKEY_SHADER_TESSELATION   "?sh.ts",0,0
#define	AI_MATKEY_SHADER_PRIMITIVE   "?sh.ps",0,0
#define	AI_MATKEY_SHADER_COMPUTE   "?sh.cs",0,0
#define	AI_MATKEY_TEXTURE(type, N)   _AI_MATKEY_TEXTURE_BASE,type,N
#define	AI_MATKEY_UVWSRC(type, N)   _AI_MATKEY_UVWSRC_BASE,type,N
#define	AI_MATKEY_TEXOP(type, N)   _AI_MATKEY_TEXOP_BASE,type,N
#define	AI_MATKEY_MAPPING(type, N)   _AI_MATKEY_MAPPING_BASE,type,N
#define	AI_MATKEY_TEXBLEND(type, N)   _AI_MATKEY_TEXBLEND_BASE,type,N
#define	AI_MATKEY_MAPPINGMODE_U(type, N)   _AI_MATKEY_MAPPINGMODE_U_BASE,type,N
#define	AI_MATKEY_MAPPINGMODE_V(type, N)   _AI_MATKEY_MAPPINGMODE_V_BASE,type,N
#define	AI_MATKEY_TEXMAP_AXIS(type, N)   _AI_MATKEY_TEXMAP_AXIS_BASE,type,N
#define	AI_MATKEY_UVTRANSFORM(type, N)   _AI_MATKEY_UVTRANSFORM_BASE,type,N
#define	AI_MATKEY_TEXFLAGS(type, N)   _AI_MATKEY_TEXFLAGS_BASE,type,N
#define	aiGetMaterialFloat
#define	aiGetMaterialInteger

Enumerations
enum	aiTextureOp {   aiTextureOp_Multiply = 0x0, aiTextureOp_Add = 0x1, aiTextureOp_Subtract = 0x2, aiTextureOp_Divide = 0x3,   aiTextureOp_SmoothAdd = 0x4, aiTextureOp_SignedAdd = 0x5, _aiTextureOp_Force32Bit = INT_MAX }
	Defines how the Nth texture of a specific type is combined with the result of all previous layers. More...
enum	aiTextureMapMode {   aiTextureMapMode_Wrap = 0x0, aiTextureMapMode_Clamp = 0x1, aiTextureMapMode_Decal = 0x3, aiTextureMapMode_Mirror = 0x2,   _aiTextureMapMode_Force32Bit = INT_MAX }
	Defines how UV coordinates outside the [0...1] range are handled. More...
enum	aiTextureMapping {   aiTextureMapping_UV = 0x0, aiTextureMapping_SPHERE = 0x1, aiTextureMapping_CYLINDER = 0x2, aiTextureMapping_BOX = 0x3,   aiTextureMapping_PLANE = 0x4, aiTextureMapping_OTHER = 0x5, _aiTextureMapping_Force32Bit = INT_MAX }
	Defines how the mapping coords for a texture are generated. More...
enum	aiTextureType {   aiTextureType_NONE = 0, aiTextureType_DIFFUSE = 1, aiTextureType_SPECULAR = 2, aiTextureType_AMBIENT = 3,   aiTextureType_EMISSIVE = 4, aiTextureType_HEIGHT = 5, aiTextureType_NORMALS = 6, aiTextureType_SHININESS = 7,   aiTextureType_OPACITY = 8, aiTextureType_DISPLACEMENT = 9, aiTextureType_LIGHTMAP = 10, aiTextureType_REFLECTION = 11,   aiTextureType_BASE_COLOR = 12, aiTextureType_NORMAL_CAMERA = 13, aiTextureType_EMISSION_COLOR = 14, aiTextureType_METALNESS = 15,   aiTextureType_DIFFUSE_ROUGHNESS = 16, aiTextureType_AMBIENT_OCCLUSION = 17, aiTextureType_UNKNOWN = 18, _aiTextureType_Force32Bit = INT_MAX }
	Defines the purpose of a texture. More...
enum	aiShadingMode {   aiShadingMode_Flat = 0x1, aiShadingMode_Gouraud = 0x2, aiShadingMode_Phong = 0x3, aiShadingMode_Blinn = 0x4,   aiShadingMode_Toon = 0x5, aiShadingMode_OrenNayar = 0x6, aiShadingMode_Minnaert = 0x7, aiShadingMode_CookTorrance = 0x8,   aiShadingMode_NoShading = 0x9, aiShadingMode_Fresnel = 0xa, _aiShadingMode_Force32Bit = INT_MAX }
	Defines all shading models supported by the library. More...
enum	aiTextureFlags { aiTextureFlags_Invert = 0x1, aiTextureFlags_UseAlpha = 0x2, aiTextureFlags_IgnoreAlpha = 0x4, _aiTextureFlags_Force32Bit = INT_MAX }
	Defines some mixed flags for a particular texture. More...
enum	aiBlendMode { aiBlendMode_Default = 0x0, aiBlendMode_Additive = 0x1, _aiBlendMode_Force32Bit = INT_MAX }
	Defines alpha-blend flags. More...

Functions
ASSIMP_API const char *	TextureTypeToString (enum aiTextureType in)
ASSIMP_API C_ENUM aiReturn	aiGetMaterialProperty (const C_STRUCT aiMaterial *pMat, const char *pKey, unsigned int type, unsigned int index, const C_STRUCT aiMaterialProperty **pPropOut)
	Retrieve a material property with a specific key from the material. More...
ASSIMP_API C_ENUM aiReturn	aiGetMaterialFloatArray (const C_STRUCT aiMaterial *pMat, const char *pKey, unsigned int type, unsigned int index, ai_real *pOut, unsigned int *pMax)
	Retrieve an array of float values with a specific key from the material. More...
ASSIMP_API C_ENUM aiReturn	aiGetMaterialIntegerArray (const C_STRUCT aiMaterial *pMat, const char *pKey, unsigned int type, unsigned int index, int *pOut, unsigned int *pMax)
	__cplusplus More...
ASSIMP_API C_ENUM aiReturn	aiGetMaterialColor (const C_STRUCT aiMaterial *pMat, const char *pKey, unsigned int type, unsigned int index, C_STRUCT aiColor4D *pOut)
	__cplusplus More...
ASSIMP_API C_ENUM aiReturn	aiGetMaterialUVTransform (const C_STRUCT aiMaterial *pMat, const char *pKey, unsigned int type, unsigned int index, C_STRUCT aiUVTransform *pOut)
	Retrieve a aiUVTransform value from the material property table. More...
ASSIMP_API C_ENUM aiReturn	aiGetMaterialString (const C_STRUCT aiMaterial *pMat, const char *pKey, unsigned int type, unsigned int index, C_STRUCT aiString *pOut)
	Retrieve a string from the material property table. More...
ASSIMP_API unsigned int	aiGetMaterialTextureCount (const C_STRUCT aiMaterial *pMat, C_ENUM aiTextureType type)
C_ENUM aiReturn	aiGetMaterialTexture (const C_STRUCT aiMaterial *mat, C_ENUM aiTextureType type, unsigned int index, C_STRUCT aiString *path, C_ENUM aiTextureMapping *mapping, unsigned int *uvindex, ai_real *blend, C_ENUM aiTextureOp *op, C_ENUM aiTextureMapMode *mapmode, unsigned int *flags)
	Helper function to get all values pertaining to a particular texture slot from a material structure. More...

Detailed Description

Defines the material system of the library.

Macro Definition Documentation

aiGetMaterialFloat

#define aiGetMaterialFloat

Value:

    (pMat, type, index, pKey, pOut) \
    aiGetMaterialFloatArray(pMat, type, index, pKey, pOut, NULL)

aiGetMaterialInteger

#define aiGetMaterialInteger

Value:

    (pMat, type, index, pKey, pOut) \
    aiGetMaterialIntegerArray(pMat, type, index, pKey, pOut, NULL)

Enumeration Type Documentation

aiBlendMode

enum aiBlendMode

Defines alpha-blend flags.

If you're familiar with OpenGL or D3D, these flags aren't new to you. They define how the final color value of a pixel is computed, basing on the previous color at that pixel and the new color value from the material. The blend formula is:

SourceColor * SourceBlend + DestColor * DestBlend

where DestColor is the previous color in the framebuffer at this position and SourceColor is the material color before the transparency calculation.
This corresponds to the #AI_MATKEY_BLEND_FUNC property.

Enumerator
aiBlendMode_Default	Formula: SourceColor*SourceAlpha + DestColor*(1-SourceAlpha)
aiBlendMode_Additive	Additive blending Formula: @code SourceColor*1 + DestColor*1 @endcode

aiShadingMode

enum aiShadingMode

Defines all shading models supported by the library.

The list of shading modes has been taken from Blender. See Blender documentation for more information. The API does not distinguish between "specular" and "diffuse" shaders (thus the specular term for diffuse shading models like Oren-Nayar remains undefined).
Again, this value is just a hint. Assimp tries to select the shader whose most common implementation matches the original rendering results of the 3D modeller which wrote a particular model as closely as possible.

Enumerator
aiShadingMode_Flat	Flat shading. Shading is done on per-face base, diffuse only. Also known as 'faceted shading'.
aiShadingMode_Gouraud	Simple Gouraud shading.
aiShadingMode_Phong	Phong-Shading -
aiShadingMode_Blinn	Phong-Blinn-Shading
aiShadingMode_Toon	Toon-Shading per pixel Also known as 'comic' shader.
aiShadingMode_OrenNayar	OrenNayar-Shading per pixel Extension to standard Lambertian shading, taking the roughness of the material into account
aiShadingMode_Minnaert	Minnaert-Shading per pixel Extension to standard Lambertian shading, taking the "darkness" of the material into account
aiShadingMode_CookTorrance	CookTorrance-Shading per pixel Special shader for metallic surfaces.
aiShadingMode_NoShading	No shading at all. Constant light influence of 1.0.
aiShadingMode_Fresnel	Fresnel shading

aiTextureFlags

enum aiTextureFlags

Defines some mixed flags for a particular texture.

Usually you'll instruct your cg artists how textures have to look like ... and how they will be processed in your application. However, if you use Assimp for completely generic loading purposes you might also need to process these flags in order to display as many 'unknown' 3D models as possible correctly.

This corresponds to the #AI_MATKEY_TEXFLAGS property.

Enumerator
aiTextureFlags_Invert	The texture's color values have to be inverted (component-wise 1-n)
aiTextureFlags_UseAlpha	Explicit request to the application to process the alpha channel of the texture. Mutually exclusive with aiTextureFlags_IgnoreAlpha. These flags are set if the library can say for sure that the alpha channel is used/is not used. If the model format does not define this, it is left to the application to decide whether the texture alpha channel - if any - is evaluated or not.
aiTextureFlags_IgnoreAlpha	Explicit request to the application to ignore the alpha channel of the texture. Mutually exclusive with aiTextureFlags_UseAlpha.

aiTextureMapMode

enum aiTextureMapMode

Defines how UV coordinates outside the [0...1] range are handled.

Commonly referred to as 'wrapping mode'.

Enumerator
aiTextureMapMode_Wrap	A texture coordinate u|v is translated to u%1|v%1
aiTextureMapMode_Clamp	Texture coordinates outside [0...1] are clamped to the nearest valid value.
aiTextureMapMode_Decal	If the texture coordinates for a pixel are outside [0...1] the texture is not applied to that pixel
aiTextureMapMode_Mirror	A texture coordinate u|v becomes u%1|v%1 if (u-(u%1))%2 is zero and 1-(u%1)|1-(v%1) otherwise

aiTextureMapping

enum aiTextureMapping

Defines how the mapping coords for a texture are generated.

Real-time applications typically require full UV coordinates, so the use of the aiProcess_GenUVCoords step is highly recommended. It generates proper UV channels for non-UV mapped objects, as long as an accurate description how the mapping should look like (e.g spherical) is given. See the #AI_MATKEY_MAPPING property for more details.

Enumerator
aiTextureMapping_UV	The mapping coordinates are taken from an UV channel. The #AI_MATKEY_UVWSRC key specifies from which UV channel the texture coordinates are to be taken from (remember, meshes can have more than one UV channel).
aiTextureMapping_SPHERE	Spherical mapping
aiTextureMapping_CYLINDER	Cylindrical mapping
aiTextureMapping_BOX	Cubic mapping
aiTextureMapping_PLANE	Planar mapping
aiTextureMapping_OTHER	Undefined mapping. Have fun.

aiTextureOp

enum aiTextureOp

Defines how the Nth texture of a specific type is combined with the result of all previous layers.

Example (left: key, right: value):

DiffColor0     - gray
DiffTextureOp0 - aiTextureOpMultiply
DiffTexture0   - tex1.png
DiffTextureOp0 - aiTextureOpAdd
DiffTexture1   - tex2.png

Written as equation, the final diffuse term for a specific pixel would be:

diffFinal = DiffColor0 * sampleTex(DiffTexture0,UV0) +
   sampleTex(DiffTexture1,UV0) * diffContrib;

where 'diffContrib' is the intensity of the incoming light for that pixel.

Enumerator
aiTextureOp_Multiply	T = T1 * T2
aiTextureOp_Add	T = T1 + T2
aiTextureOp_Subtract	T = T1 - T2
aiTextureOp_Divide	T = T1 / T2
aiTextureOp_SmoothAdd	T = (T1 + T2) - (T1 * T2)
aiTextureOp_SignedAdd	T = T1 + (T2-0.5)

aiTextureType

enum aiTextureType

Defines the purpose of a texture.

This is a very difficult topic. Different 3D packages support different kinds of textures. For very common texture types, such as bumpmaps, the rendering results depend on implementation details in the rendering pipelines of these applications. Assimp loads all texture references from the model file and tries to determine which of the predefined texture types below is the best choice to match the original use of the texture as closely as possible.

In content pipelines you'll usually define how textures have to be handled, and the artists working on models have to conform to this specification, regardless which 3D tool they're using.

Enumerator
aiTextureType_NONE	Dummy value. No texture, but the value to be used as 'texture semantic' (#aiMaterialProperty::mSemantic) for all material properties *not* related to textures.
aiTextureType_DIFFUSE	LEGACY API MATERIALS Legacy refers to materials which Were originally implemented in the specifications around 2000. These must never be removed, as most engines support them. The texture is combined with the result of the diffuse lighting equation.
aiTextureType_SPECULAR	The texture is combined with the result of the specular lighting equation.
aiTextureType_AMBIENT	The texture is combined with the result of the ambient lighting equation.
aiTextureType_EMISSIVE	The texture is added to the result of the lighting calculation. It isn't influenced by incoming light.
aiTextureType_HEIGHT	The texture is a height map. By convention, higher gray-scale values stand for higher elevations from the base height.
aiTextureType_NORMALS	The texture is a (tangent space) normal-map. Again, there are several conventions for tangent-space normal maps. Assimp does (intentionally) not distinguish here.
aiTextureType_SHININESS	The texture defines the glossiness of the material. The glossiness is in fact the exponent of the specular (phong) lighting equation. Usually there is a conversion function defined to map the linear color values in the texture to a suitable exponent. Have fun.
aiTextureType_OPACITY	The texture defines per-pixel opacity. Usually 'white' means opaque and 'black' means 'transparency'. Or quite the opposite. Have fun.
aiTextureType_DISPLACEMENT	Displacement texture The exact purpose and format is application-dependent. Higher color values stand for higher vertex displacements.
aiTextureType_LIGHTMAP	Lightmap texture (aka Ambient Occlusion) Both 'Lightmaps' and dedicated 'ambient occlusion maps' are covered by this material property. The texture contains a scaling value for the final color value of a pixel. Its intensity is not affected by incoming light.
aiTextureType_REFLECTION	Reflection texture Contains the color of a perfect mirror reflection. Rarely used, almost never for real-time applications.
aiTextureType_BASE_COLOR	PBR Materials PBR definitions from maya and other modelling packages now use this standard. This was originally introduced around 2012. Support for this is in game engines like Godot, Unreal or Unity3D. Modelling packages which use this are very common now.
aiTextureType_UNKNOWN	Unknown texture A texture reference that does not match any of the definitions above is considered to be 'unknown'. It is still imported, but is excluded from any further post-processing.

Function Documentation

aiGetMaterialColor()

ASSIMP_API C_ENUM aiReturn aiGetMaterialColor	(	const C_STRUCT aiMaterial *	pMat,
		const char *	pKey,
		unsigned int	type,
		unsigned int	index,
		C_STRUCT aiColor4D *	pOut
	)

__cplusplus

Retrieve a color value from the material property table

See the sample for aiGetMaterialFloat for more information

aiGetMaterialFloatArray()

ASSIMP_API C_ENUM aiReturn aiGetMaterialFloatArray	(	const C_STRUCT aiMaterial *	pMat,
		const char *	pKey,
		unsigned int	type,
		unsigned int	index,
		ai_real *	pOut,
		unsigned int *	pMax
	)

Retrieve an array of float values with a specific key from the material.

Pass one of the AI_MATKEY_XXX constants for the last three parameters (the example reads the #AI_MATKEY_UVTRANSFORM property of the first diffuse texture)

aiUVTransform trafo;
unsigned int max = sizeof(aiUVTransform);
if (AI_SUCCESS != aiGetMaterialFloatArray(mat, AI_MATKEY_UVTRANSFORM(aiTextureType_DIFFUSE,0),
   (float*)&trafo, &max) || sizeof(aiUVTransform) != max)
{
  // error handling
}

Parameters

pMat	Pointer to the input material. May not be NULL
pKey	Key to search for. One of the AI_MATKEY_XXX constants.
pOut	Pointer to a buffer to receive the result.
pMax	Specifies the size of the given buffer, in float's. Receives the number of values (not bytes!) read.
type	(see the code sample above)
index	(see the code sample above)

Returns

Specifies whether the key has been found. If not, the output arrays remains unmodified and pMax is set to 0.

aiGetMaterialIntegerArray()

ASSIMP_API C_ENUM aiReturn aiGetMaterialIntegerArray	(	const C_STRUCT aiMaterial *	pMat,
		const char *	pKey,
		unsigned int	type,
		unsigned int	index,
		int *	pOut,
		unsigned int *	pMax
	)

__cplusplus

Retrieve an array of integer values with a specific key from a material

See the sample for aiGetMaterialFloatArray for more information.

aiGetMaterialProperty()

ASSIMP_API C_ENUM aiReturn aiGetMaterialProperty	(	const C_STRUCT aiMaterial *	pMat,
		const char *	pKey,
		unsigned int	type,
		unsigned int	index,
		const C_STRUCT aiMaterialProperty **	pPropOut
	)

Retrieve a material property with a specific key from the material.

Parameters

pMat	Pointer to the input material. May not be NULL
pKey	Key to search for. One of the AI_MATKEY_XXX constants.
type	Specifies the type of the texture to be retrieved ( e.g. diffuse, specular, height map ...)
index	Index of the texture to be retrieved.
pPropOut	Pointer to receive a pointer to a valid aiMaterialProperty structure or NULL if the key has not been found.

aiGetMaterialString()

ASSIMP_API C_ENUM aiReturn aiGetMaterialString	(	const C_STRUCT aiMaterial *	pMat,
		const char *	pKey,
		unsigned int	type,
		unsigned int	index,
		C_STRUCT aiString *	pOut
	)

Retrieve a string from the material property table.

See the sample for aiGetMaterialFloat for more information.

aiGetMaterialTexture()

C_ENUM aiReturn aiGetMaterialTexture	(	const C_STRUCT aiMaterial *	mat,
		C_ENUM aiTextureType	type,
		unsigned int	index,
		C_STRUCT aiString *	path,
		C_ENUM aiTextureMapping *	mapping,
		unsigned int *	uvindex,
		ai_real *	blend,
		C_ENUM aiTextureOp *	op,
		C_ENUM aiTextureMapMode *	mapmode,
		unsigned int *	flags
	)

Helper function to get all values pertaining to a particular texture slot from a material structure.

This function is provided just for convenience. You could also read the texture by parsing all of its properties manually. This function bundles all of them in a huge function monster.

Parameters

[in]	mat	Pointer to the input material. May not be NULL
[in]	type	Specifies the texture stack to read from (e.g. diffuse, specular, height map ...).
[in]	index	Index of the texture. The function fails if the requested index is not available for this texture type. aiGetMaterialTextureCount() can be used to determine the number of textures in a particular texture stack.
[out]	path	Receives the output path If the texture is embedded, receives a '*' followed by the id of the texture (for the textures stored in the corresponding scene) which can be converted to an int using a function like atoi. This parameter must be non-null.
	mapping	The texture mapping mode to be used. Pass NULL if you're not interested in this information.
[out]	uvindex	For UV-mapped textures: receives the index of the UV source channel. Unmodified otherwise. Pass NULL if you're not interested in this information.
[out]	blend	Receives the blend factor for the texture Pass NULL if you're not interested in this information.
[out]	op	Receives the texture blend operation to be perform between this texture and the previous texture. Pass NULL if you're not interested in this information.
[out]	mapmode	Receives the mapping modes to be used for the texture. Pass NULL if you're not interested in this information. Otherwise, pass a pointer to an array of two aiTextureMapMode's (one for each axis, UV order).
[out]	flags	Receives the the texture flags.

Returns

AI_SUCCESS on success, otherwise something else. Have fun.

aiGetMaterialTextureCount()

ASSIMP_API unsigned int aiGetMaterialTextureCount	(	const C_STRUCT aiMaterial *	pMat,
		C_ENUM aiTextureType	type
	)

Get the number of textures for a particular texture type.

Parameters

[in]	pMat	Pointer to the input material. May not be NULL
	type	Texture type to check for

Returns

Number of textures for this type.

Note

A texture can be easily queried using aiGetMaterialTexture()

aiGetMaterialUVTransform()

ASSIMP_API C_ENUM aiReturn aiGetMaterialUVTransform	(	const C_STRUCT aiMaterial *	pMat,
		const char *	pKey,
		unsigned int	type,
		unsigned int	index,
		C_STRUCT aiUVTransform *	pOut
	)

Retrieve a aiUVTransform value from the material property table.

See the sample for aiGetMaterialFloat for more information