OpenGL Headline News
Apr 25, 2005
This demo uses the Nvidia OpenGL API extension NV_fragment_program2 aka Pixel Shader 3.0 to create a soft shadows where the penumbra is generated by jittering the sampling position up to 64 times and averaging the results. The advantage of Pixel Shader 3.0 is that you don’t have to over sample unless on a shadow edge. If you detect that you’re on a lit or completely shadowed area, you can skip the 28 x 2* of 32x2* texture fetch necessary to blur the penumbra, yielding performance gains up to 50%.