Hi, I've just finished implementing GJK for collision detection in my 2D physics engine. However, I'm trying to modify my implementation so that it will work with circles as well. Normally, this would be pretty straight forward since a support function for a circle is really simple (circle.pos + |dir|*radius). However, I'm also warmstarting my GJK implementation using the cached support vertices from the previous frame. Since circles obviously don't have vertices (to cache say the index), and the actual support point will change between frames it suddenly doesn't seem so clear. Does anyone have a good suggestion on how to go about caching a simplex that also involves a circle?