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Fragment lighting is implemented as an optional pipeline step during pixel processing. It's implemented by having the vertex shader output an additional attribute describing the transformation (represented by a quaternion) to surface-local space. This per-vertex quaternion can then be interpolated across screen space to calculate dot products relevant for lighting (e.g. light vector dot normal vector). To provide support for advanced lighting models, these dot products are used as indices into programmable lookup tables. With this setup, PICA200 in particular supports the shading models Blinn-Phong, Cook-Terrance, Ward, and microfacet-based BRDF-models.
Fragment lighting is implemented as an optional pipeline step during pixel processing. It's implemented by having the vertex shader output an additional attribute describing the transformation (represented by a quaternion) to surface-local space. This per-vertex quaternion can then be interpolated across screen space to calculate dot products relevant for lighting (e.g. light vector dot normal vector). To provide support for advanced lighting models, these dot products are used as indices into programmable lookup tables. With this setup, PICA200 in particular supports the shading models Blinn-Phong, Cook-Terrance, Ward, and microfacet-based BRDF-models.
PICA200 supports four texture units, the fourth of which is used exclusively for [[GPU/Procedural Texture Generation|procedural texture generation]].
== SDIO controller ==
== SDIO controller ==