Texture unit. 
| Enumerator | 
|---|
| Graphic3d_TextureUnit_0 |  | 
| Graphic3d_TextureUnit_1 |  | 
| Graphic3d_TextureUnit_2 |  | 
| Graphic3d_TextureUnit_3 |  | 
| Graphic3d_TextureUnit_4 |  | 
| Graphic3d_TextureUnit_5 |  | 
| Graphic3d_TextureUnit_6 |  | 
| Graphic3d_TextureUnit_7 |  | 
| Graphic3d_TextureUnit_8 |  | 
| Graphic3d_TextureUnit_9 |  | 
| Graphic3d_TextureUnit_10 |  | 
| Graphic3d_TextureUnit_11 |  | 
| Graphic3d_TextureUnit_12 |  | 
| Graphic3d_TextureUnit_13 |  | 
| Graphic3d_TextureUnit_14 |  | 
| Graphic3d_TextureUnit_15 |  | 
| Graphic3d_TextureUnit_BaseColor | sampler2D occSamplerBaseColor. RGB(A) base color of the material and alpha mask/opacity.  | 
| Graphic3d_TextureUnit_Emissive | sampler2D occSamplerEmissive. RGB emissive map controls the color and intensity of the light being emitted by the material.  | 
| Graphic3d_TextureUnit_Occlusion | sampler2D occSamplerOcclusion. Occlusion map indicating areas of indirect lighting. Encoded into RED channel, with 1.0 meaning no occlusion (full color intensity) and 0.0 complete occlusion (black).  | 
| Graphic3d_TextureUnit_Normal | sampler2D occSamplerNormal. XYZ tangent space normal map.  | 
| Graphic3d_TextureUnit_MetallicRoughness | sampler2D occSamplerMetallicRoughness. Metalness + roughness of the material. Encoded into GREEN (roughness) + BLUE (metallic) channels, so that it can be optionally combined with occlusion texture (RED channel).  | 
| Graphic3d_TextureUnit_EnvMap | samplerCube occSampler0. Environment cubemap for background. Rendered by dedicated program and normally occupies first texture unit.  | 
| Graphic3d_TextureUnit_PointSprite | sampler2D occSamplerPointSprite. Sprite alpha-mask or RGBA image mapped using point UV, additional to BaseColor (mapping using vertex UV). This texture unit is set Graphic3d_TextureUnit_1, so that it can be combined with Graphic3d_TextureUnit_BaseColor, while other texture maps (normal map and others) are unexpected and unsupported for points. Note that it can be overridden to Graphic3d_TextureUnit_0 for FFP fallback on hardware without multi-texturing.  | 
| Graphic3d_TextureUnit_DepthPeelingDepth | sampler2D occDepthPeelingDepth. 1st texture unit for Depth Peeling lookups.  | 
| Graphic3d_TextureUnit_DepthPeelingFrontColor | sampler2D occDepthPeelingFrontColor. 2nd texture unit for Depth Peeling lookups.  | 
| Graphic3d_TextureUnit_ShadowMap | sampler2D occShadowMapSampler. Directional light source shadowmap texture.  | 
| Graphic3d_TextureUnit_PbrEnvironmentLUT | sampler2D occEnvLUT. Lookup table for approximated PBR environment lighting. Configured as index at the end of available texture units - 3.  | 
| Graphic3d_TextureUnit_PbrIblDiffuseSH | sampler2D occDiffIBLMapSHCoeffs. Diffuse (irradiance) IBL map's spherical harmonics coefficients baked for PBR from environment cubemap image. Configured as index at the end of available texture units - 2.  | 
| Graphic3d_TextureUnit_PbrIblSpecular | samplerCube occSpecIBLMap. Specular IBL (Image-Based Lighting) environment map baked for PBR from environment cubemap image. Configured as index at the end of available texture units - 1.  |