Hi, I've been trying to write a simple separating axis collision detection function between two polygons in C and I can't find any working example code. I don't really care what language it's in, as long as I can run it on my mac and can then port it to C. I'm also simultaneously working on the same thing in Processing, just for testing purposes. You can view the Processing Java Applet here: http://magneon.ath.cx/Test (source file linked from the page) to see what my problem is (the collision is just a little bit off on one side). If anyone has any links or example code lying around I would greatly appreciate it.

I wouldn't use that code though. I would first read this and this, and use that code.

and a physics demo here.

Thanks for the great replies guys, I've read through everything :). I still can't get my code to work :(. I'm using C, and I can't get your C++ code to run (I'm compiling from a mac). I have a method that works fine for stationary objects (checking vertex incusion and edge intersection) but this doesn't give me anything to work with for collision response. I would like my end function to look something like this:

int polyCollide(float polyA[][32], int numVertexA,float polyB[][32], int numVertexB, float &polyAXSpeed,float &polyAYSpeed,float &polyAX, float &polyAY, float polyBX,float polyBY){   //here be the little bit I'm missing   if(polygonsCollide){ return 1; }else{ return 0;}}

where polyAX/YSpeed are pointers to the speed of the first polygon's speed. If a collision takes place the pointers for polygon a's speed and position get updated to reflect the collision. Polygon B is immobile. I would really rather know what to do and code this myself rather than borrow someone elses code (although after a few days of smashing my brain against this problem I'm not sure if it's worth the offort).

Does anyone have examples/tutorials anything in C?

Thanks,
Joseph

I dunno what to say more... in the thread I presented, I posted a method to do what you asked, as well as C source code. Well, it's C done with C++, but it is relatively straight forward.

If you don;t understand the code, your problem is not with the collision stuff, but with c/c++.