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O-san

OpenGL Flickering lighting

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Hello! I'm having problems with standard OpenGL lighting enabled with GL_SEPARATE_SPECULAR_COLOR. I've got a normal pointing let's say 0, 0, 1 and my light rays hit this polygon in a parallel way to the polygon. The lighting/surface then starts to flicker when I move the view… How can I avoid this? I think it's because the rays hit the surface at "no angle". I don't want to slightly noise my polygon normal or some other work-around like that... any ideas what could cause this problem? An image showing my polygon normal and a light ray (line with arrow):
An image showing the problem in action, to the right the view has changed slightly. Lighting on the mud has become distorted:

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I take it you are using hardware lightmapping?

if so make sure you don't have Z-fighting going on!

do this by adding
glPolygonOffset(1, 1);
glEnable(GL_POLYGON_OFFSET);
...
glDisable(GL_POLYGON_OFFSET);

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