I can do collision detection using ray-triangle intersection. How do I check for collision between rotating and/or skeletaly animated shapes? Do I need to do matrix transformations using the CPU? If so, is there a fast way of doing matrix and vector operations?

Edit: I'm making 3d not 2d games

-Ummon

That's something you should do anyway: if you do them with the GPU using for the separate parts (like with glBegin and glEnd), the polygons will be "broken" rather than connected. You might want to look into using quaternions, though: they'll be a little bit easier on the processor.

You could sweep the triangles across the path they will move along and perfom ray/3D object intersection with that, its a lot more easy though to do find an instantaneous intersection check and subdivide time until you know the exact* point in time a collision occurs.

Is there any page that shows how to use quaternions directly for transformations rather than just to avoid gimbal lock?

this is a good read
http://www.geometrictools.com/Documentat...rnions.pdf

bear in mind quaternions are not THE solution for 3D rotation, somthing else may be easier/better etc.

Thanks, I'll read that.