Microsoft DirectX 8.0 (Visual Basic) |
Dot products require signed data, so you need to convert the inputs using the _bx2 argument modifier. Lighting clamps negative values using the _sat instruction modifier.
// Diffuse is the light direction. ps.1.0 // DirectX8 Version tex t0 // The normal map dp3_sat r0, t0_bx2, v0_bx2