Microsoft DirectX 8.0 (C++) |
These are the texture registers. There are as many texture registers as there are simultaneous textures supported. The texture registers are initialized to contain texture colors from the texture sampling units including filtering modes defined by that stage's texture stage state. The colors come from their corresponding textures as defined by IDirect3DDevice8::SetTexture and sampled at the corresponding texture coordinates.
Any texture register that does not have a texture set will be sampled as opaque black (0,0,0,1). A maximum of two texture registers can appear in any single shader instruction. Texture registers may also be used as temporary registers. Specifically, after the texture addressing instructions, these registers can be used as read/write temporary registers.
In most cases, a texture register is only valid as a destination of a texture command; however, note that the arithmetic instructions can read from texture registers.