Anyone managed to get 2-sided GLSL lighting working in QC? I'm actually trying to implement a very simple 'fake' lighting effect in a GLSL Shader patch, whereby the colour at each fragment is a product of it's distance from an arbitrary light-source position. I have this working already, but I'd like to be able to shade the front and back-facing sides of a mesh with different base-colours.I've tried using gl_FrontColor and gl_BackColorset to different colours in the Vertex Shader, but the front color is always used for both faces, even if I embed the GLSL Shader patch inside a Lighting Patch with the 'Use 2-sided lighting' option enabled.
2-sided lighting doesn't deal with gl_BackColor, it only determines whether or not certain lighting calculations are performed on non- front-facing polys. If it were to set gl_BackColor, there'd have to be another input somewhere to control it (gltools feature request? ;)
You can see the effects of it here -- 2 teapots, both with front- facing polygons culled. The left one is "normal" lighting, the second is "2-sided". Otherwise, they're identical. Note the inner specular highlights on the right teapot -- that's what this does.
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-- [ christopher wright ] [EMAIL PROTECTED] http://kineme.net/
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