how to do polygon collision/overlap?

[kelvin]

is there an easy way to do tell if a polygon overlaps another polygon in OpenGL? I want to use this kind of test for collision detection.

[OneSadCookie]

No.

Don't do collision detection in GL, even if you can find a hack way to do it — the readback from graphics card to CPU will kill performance.

[kelvin]

well, my main issues was that I have multiple matricies pushed on to the model matrix stack, so with rotation, and scaling, it's going to be a big pain in the butt to figure out actual polygon positions.:shock:

[OneSadCookie]

gluProject/gluUnProject are your friends.