Following the poll, buoyancy seemed to be the popular choice for Box2D feature. I decided against the fancy and probably unreliable technique I was going to use, and have produced a “controller” based on good old, geometry, cribbing a fair amount of Erin Catto’s notes on the subject. Demo
My first proper contribution to the wonderful Box2D engine, specifically the Flash port. I’ve added a third shape type to the engine, which dramatically increases the possible shapes you can describe. Hopefully my contribution will also show other people how to add shapes, and some of the deeper aspects of the engine.
It’s easier to describe than see, so try out a demo: Demo