Chipmunk Physics

how can textures be changed in chipmunk and how are sprites changed so for example in a collision sprite A changes to sprite B

Chipmunk doesn't do any rendering (other than the debug rendering used in the demos). So changing a texture/sprite is completely up to whatever graphics library you are using.

You would set up a collision handler to detect the collision however: http://chipmunk-physics.net/release/Chi ... nCallbacks