Microsoft DirectX 8.0 (C++) |
These are the vertex color registers. The input vertex color registers contain color values obtained by per-pixel Gouraud iteration of the color values emitted by the vertex shader (which may in turn receive them from the vertex stream). A compliant Microsoft® DirectX® 8.0 implementation must support at least two of the input color registers.
Input color registers are read-only, and a maximum of one of these colors can be used in any one instruction.
To simulate flat shading, a constant color is more efficient. However, when the shade mode is D3DSHADE_FLAT, applications iteration of both colors is disabled. Note that fog should continue to be iterated. Ideally, all color iteration should be perspective correct in the same manner as the texture coordinate iteration.