Hello Raymond, I have a small question to make sure that I understand the lighting > properly. I am using GLSL to do my lighting and I would like to be 100% sure > that the call > stateSet->setMode(GL_LIGHT0 + id, osg::StateAttribute::ON); > is not necessary for lighting with GLSL. I assume that this call is for > fixed functionality OpenGL only, is this correct? Or is it used for other > purposes too?
You're totally right. When using shaders, you'll need to maintain an integer count of the number of enabled lights (if you take care to always group all your enabled lights together from 0) or a bool array of the state of lights (8 booleans, to say if light at index i [0..7] is enabled or not). Then in your shader you need to loop from 0 to 7, check if light i is enabled, and do the appropriate calculations depending on light type for that light source. Or you can do it in some other way, that's just the classic way to emulate the fixed pipeline. On this site: http://www.mew.cx/glsl/ you can find a tool called "ShaderGen" which lets you play with the different features of the fixed pipeline, and then generates shaders that emulate those features. You can do some various hand-optimizations afterwards, but it's a good starting point if you want to see what it looks like. Hope this helps, J-S -- ______________________________________________________ Jean-Sebastien Guay jean-sebastien.g...@cm-labs.com http://whitestar02.webhop.org/
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