How to deal with Normals in opengl?
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Posted 18 June 2001 - 04:08 AM
I have a problem.... i create my geometry from scratch before entering the render task, for example: (-5, 0, 5) (5, 0, 5) (5, 0, -5) (-5, 0, -5) define a plane perpendicular to the y-axis, so the unit normal is 1. this normal is precalculated before entering the main loop. when i move and rotate through the world, i use glRotate and glTranslate and then pass the calculated normal (which remains the same as well as the vertex of the plane). but if i take a dot product on any polys vertex and normal, for example, to test backface culling, it does not work correctly. do i have to rotate the corresponding poly and normal coords as well by the current angles? thankful, gammastrahler