A callback function that must be implemented by a user to set an array of vertex shader floating-point constants.
HRESULT SetPixelShaderConstantF( UINT StartRegister, CONST FLOAT* pConstantData, UINT RegisterCount );
The user-implemented method should return S_OK. If the callback fails when setting the device state, either of the following will occur:
Header: Declared in D3dx9effect.h.