Adds another buffer to the ID3DXPRTBuffer and stores the results in ID3DXPRTBuffer.
HRESULT AddBuffer( LPD3DXPRTBUFFER pBuffer );
If the method succeeds, the return value is S_OK. If the method fails, the following value will be returned.
D3DERR_INVALIDCALLpBuffer and ID3DXPRTBuffer must have the same number of samples, coefficients, and color channels; the method will fail otherwise.
Header: Declared in D3dx9mesh.h.