Environment Mapping with Standard Diffuse Lighting

Standard diffuse lighting calculations for Gouraud shading of diffuse components can be performed in the geometry pipeline. However, for best realism, the specular component can be generated by cube environment mapping. When both are in operation, the FVF specified by the application should contain one vector in the position for the lighting computation, and a separate 3D texture coordinate set for use as the vector into the cube map.