Assimp  v3.0 (July 2012)
Classes | Macros | Enumerations | Variables
material.h File Reference

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

Classes

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

Macros

#define AI_DEFAULT_MATERIAL_NAME   "DefaultMaterial"
#define AI_MATKEY_BLEND_FUNC   "$mat.blend",0,0
#define AI_MATKEY_BUMPSCALING   "$mat.bumpscaling",0,0
#define AI_MATKEY_COLOR_AMBIENT   "$clr.ambient",0,0
#define AI_MATKEY_COLOR_DIFFUSE   "$clr.diffuse",0,0
#define AI_MATKEY_COLOR_EMISSIVE   "$clr.emissive",0,0
#define AI_MATKEY_COLOR_REFLECTIVE   "$clr.reflective",0,0
#define AI_MATKEY_COLOR_SPECULAR   "$clr.specular",0,0
#define AI_MATKEY_COLOR_TRANSPARENT   "$clr.transparent",0,0
#define AI_MATKEY_ENABLE_WIREFRAME   "$mat.wireframe",0,0
#define AI_MATKEY_GLOBAL_BACKGROUND_IMAGE   "?bg.global",0,0
#define AI_MATKEY_MAPPING(type, N)   _AI_MATKEY_MAPPING_BASE,type,N
#define AI_MATKEY_MAPPINGMODE_U(type, N)   _AI_MATKEY_MAPPINGMODE_U_BASE,type,N
#define AI_MATKEY_MAPPINGMODE_V(type, N)   _AI_MATKEY_MAPPINGMODE_V_BASE,type,N
#define AI_MATKEY_NAME   "?mat.name",0,0
#define AI_MATKEY_OPACITY   "$mat.opacity",0,0
#define AI_MATKEY_REFLECTIVITY   "$mat.reflectivity",0,0
#define AI_MATKEY_REFRACTI   "$mat.refracti",0,0
#define AI_MATKEY_SHADING_MODEL   "$mat.shadingm",0,0
#define AI_MATKEY_SHININESS   "$mat.shininess",0,0
#define AI_MATKEY_SHININESS_STRENGTH   "$mat.shinpercent",0,0
#define AI_MATKEY_TEXBLEND(type, N)   _AI_MATKEY_TEXBLEND_BASE,type,N
#define AI_MATKEY_TEXFLAGS(type, N)   _AI_MATKEY_TEXFLAGS_BASE,type,N
#define AI_MATKEY_TEXMAP_AXIS(type, N)   _AI_MATKEY_TEXMAP_AXIS_BASE,type,N
#define AI_MATKEY_TEXOP(type, N)   _AI_MATKEY_TEXOP_BASE,type,N
#define AI_MATKEY_TEXTURE(type, N)   _AI_MATKEY_TEXTURE_BASE,type,N
#define AI_MATKEY_TWOSIDED   "$mat.twosided",0,0
#define AI_MATKEY_UVTRANSFORM(type, N)   _AI_MATKEY_UVTRANSFORM_BASE,type,N
#define AI_MATKEY_UVWSRC(type, N)   _AI_MATKEY_UVWSRC_BASE,type,N
#define AI_TEXTURE_TYPE_MAX   aiTextureType_UNKNOWN

Enumerations

enum  aiBlendMode { aiBlendMode_Default = 0x0, aiBlendMode_Additive = 0x1 }
 Defines alpha-blend flags. 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
}
 Defines all shading models supported by the library. More...
enum  aiTextureFlags { aiTextureFlags_Invert = 0x1, aiTextureFlags_UseAlpha = 0x2, aiTextureFlags_IgnoreAlpha = 0x4 }
 Defines some mixed flags for a particular texture. More...
enum  aiTextureMapMode { aiTextureMapMode_Wrap = 0x0, aiTextureMapMode_Clamp = 0x1, aiTextureMapMode_Decal = 0x3, aiTextureMapMode_Mirror = 0x2 }
 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
}
 Defines how the mapping coords for a texture are generated. More...
enum  aiTextureOp {
  aiTextureOp_Multiply = 0x0, aiTextureOp_Add = 0x1, aiTextureOp_Subtract = 0x2, aiTextureOp_Divide = 0x3,
  aiTextureOp_SmoothAdd = 0x4, aiTextureOp_SignedAdd = 0x5
}
 Defines how the Nth texture of a specific type is combined with the result of all previous layers. More...
enum  aiTextureType {
  aiTextureType_NONE = 0x0, aiTextureType_DIFFUSE = 0x1, aiTextureType_SPECULAR = 0x2, aiTextureType_AMBIENT = 0x3,
  aiTextureType_EMISSIVE = 0x4, aiTextureType_HEIGHT = 0x5, aiTextureType_NORMALS = 0x6, aiTextureType_SHININESS = 0x7,
  aiTextureType_OPACITY = 0x8, aiTextureType_DISPLACEMENT = 0x9, aiTextureType_LIGHTMAP = 0xA, aiTextureType_REFLECTION = 0xB,
  aiTextureType_UNKNOWN = 0xC
}
 Defines the purpose of a texture. More...

Variables

struct aiUVTransform PACK_STRUCT

Detailed Description

Defines the material system of the library.


Macro Definition Documentation

#define AI_DEFAULT_MATERIAL_NAME   "DefaultMaterial"
#define AI_MATKEY_BLEND_FUNC   "$mat.blend",0,0
#define AI_MATKEY_BUMPSCALING   "$mat.bumpscaling",0,0
#define AI_MATKEY_COLOR_AMBIENT   "$clr.ambient",0,0
#define AI_MATKEY_COLOR_DIFFUSE   "$clr.diffuse",0,0
#define AI_MATKEY_COLOR_EMISSIVE   "$clr.emissive",0,0
#define AI_MATKEY_COLOR_REFLECTIVE   "$clr.reflective",0,0
#define AI_MATKEY_COLOR_SPECULAR   "$clr.specular",0,0
#define AI_MATKEY_COLOR_TRANSPARENT   "$clr.transparent",0,0
#define AI_MATKEY_ENABLE_WIREFRAME   "$mat.wireframe",0,0
#define AI_MATKEY_GLOBAL_BACKGROUND_IMAGE   "?bg.global",0,0
#define AI_MATKEY_MAPPING (   type,
 
)    _AI_MATKEY_MAPPING_BASE,type,N
#define AI_MATKEY_MAPPINGMODE_U (   type,
 
)    _AI_MATKEY_MAPPINGMODE_U_BASE,type,N
#define AI_MATKEY_MAPPINGMODE_V (   type,
 
)    _AI_MATKEY_MAPPINGMODE_V_BASE,type,N
#define AI_MATKEY_NAME   "?mat.name",0,0
#define AI_MATKEY_OPACITY   "$mat.opacity",0,0
#define AI_MATKEY_REFLECTIVITY   "$mat.reflectivity",0,0
#define AI_MATKEY_REFRACTI   "$mat.refracti",0,0
#define AI_MATKEY_SHADING_MODEL   "$mat.shadingm",0,0
#define AI_MATKEY_SHININESS   "$mat.shininess",0,0
#define AI_MATKEY_SHININESS_STRENGTH   "$mat.shinpercent",0,0
#define AI_MATKEY_TEXBLEND (   type,
 
)    _AI_MATKEY_TEXBLEND_BASE,type,N
#define AI_MATKEY_TEXFLAGS (   type,
 
)    _AI_MATKEY_TEXFLAGS_BASE,type,N
#define AI_MATKEY_TEXMAP_AXIS (   type,
 
)    _AI_MATKEY_TEXMAP_AXIS_BASE,type,N
#define AI_MATKEY_TEXOP (   type,
 
)    _AI_MATKEY_TEXOP_BASE,type,N
#define AI_MATKEY_TEXTURE (   type,
 
)    _AI_MATKEY_TEXTURE_BASE,type,N
#define AI_MATKEY_TWOSIDED   "$mat.twosided",0,0
#define AI_MATKEY_UVTRANSFORM (   type,
 
)    _AI_MATKEY_UVTRANSFORM_BASE,type,N
#define AI_MATKEY_UVWSRC (   type,
 
)    _AI_MATKEY_UVWSRC_BASE,type,N
#define AI_TEXTURE_TYPE_MAX   aiTextureType_UNKNOWN

Enumeration Type Documentation

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 colro 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:

SourceColor*1 + DestColor*1

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.

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 (componentwise 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.

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

Commonly refered 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.

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.

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)

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 

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_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 postprocessing.


Variable Documentation

struct aiUVTransform PACK_STRUCT