Microsoft DirectX 8.0 (C++)

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These are the constant registers. Derived from the D3DRS_TEXTUREFACTOR constant, the constant factor registers are loaded by the application through the IDirect3DDevice8::SetPixelShaderConstant method.

The constant factor registers are read-only. There are at least eight constant factor registers defined for use by a pixel shader, but a maximum of two may be used in any one instruction.