Lighting State (Direct3D 9)
If you do not light with a vertex shader or a pixel shader, you may choose to use the lighting engine in the runtime. The lighting engine requires that the vertex data contains per-vertex normals; vertices without normal data will generate a dot product of zero in all lighting computations. The lighting calculations are covered in more detail in Mathematics of Lighting (Direct3D 9).
To enable the lighting engine, use:
SetRenderState(D3DRS_LIGHTING, TRUE);
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