but the 2D physics stuff going on here is coming along really well. The balls are responding to collisions from each other just like pool balls and bouncing correctly off the triangles.
Here's a demo or the collision system. Very much a demo rather than necessarily anything to do with the game I'm going to write with this.
Left and right arrows to rotate the direction you are facing, up and down to move forward and backwards.
I figure that a game based on this system can define objects in terms of a polygon that loosely matches its shape, plus some renderable triangles that can be textured.
I can't figure out how I'd go about texturing a level constructed of non-rectangular walls, but I'm going to cross that bridge when I come to it.