HardwareShadow Mapping Algorithm

Two pass approach



• First, render scene from light’s point-of-view with depth testing
  • Copy the depth buffer to a “depth texture”
• Second, render scene from eye’s point-of-view as follows
  • Configure eye-linear texgen to generate (s,t,r,q) coordinates in light’s coordinate space (“r” is z-planar distance to the light)
  • Configure special shadow texture filter operator
  • Texture filter tests if “r” is less than depth texture texel
  • Texture color is one if tests passes, zero if test fails
  • Modulate fragment color with one or zero texture

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