I wasn't sure if this was the right forum to ask it in, but I'm guessing it's a pretty elementary question. Anyway, some time ago I finished programming a simple sidescroller with simple rectangular collision detection (Did this in SDL). However, I decided it would be nice as I move on to know how to check for collisions on diagonal surfaces (like a rhombus for example). I tried per-pixel collision, but it caused a huge amount of lag and took forever to make simple collision boxes. So my question is, what would be the best way to go about implementing diagonal collision surfaces in a 2-D game? If you got any good tutorials on this it would be greatly appreciated. Thanks in advance.

Separating Axis Theorem

This is probably what you want.

Quote:Original post by X Abstract X
Separating Axis Theorem

This is probably what you want.

http://www.metanetsoftware.com/technique/tutorialA.html

there's a nudder one