The new EXT_depth_bounds test looks promising for the kind of stencil volume shadows that are detailed in lesson 27 of NeHe''s OpenGL Tutorials. The test would eliminate some of the infinity hacks present in stencil volume shadow programs with a fragment test between the scissor and alpha tests. This test will speed up hardware rendering of volume shadows and will be implemented in the next NV FX 5900 drivers (June 2003). The link to the spec is http://www.nvidia.com/dev_content/nvopenglspecs/GL_EXT_depth_bounds_test.txt Hope someone finds this interesting.