Assimp: material.h File Reference

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:

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.

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.

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.

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

Commonly refered to as 'wrapping mode'.

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.

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

Example (left: key, right: value):

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

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

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.

__cplusplus

Retrieve a color value from the material property table

See the sample for aiGetMaterialFloat for more information

Retrieve a single float property 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_SHININESS_STRENGTH property of the first diffuse texture)

Parameters

pMat	Pointer to the input material. May not be NULL
pKey	Key to search for. One of the AI_MATKEY_XXX constants.
pOut	Receives the output float.
type	(see the code sample above)
index	(see the code sample above)

Returns

Specifies whether the key has been found. If not, the output float remains unmodified.

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)

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.

Retrieve an integer property with a specific key from a material.

See the sample for aiGetMaterialFloat for more information.

__cplusplus

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

See the sample for aiGetMaterialFloatArray for more information.

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.

Retrieve a string from the material property table.

See the sample for aiGetMaterialFloat for more information.

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 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.

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()

Retrieve a aiUVTransform value from the material property table.

See the sample for aiGetMaterialFloat for more information