2D Physics engine to simulate gravity using images

Question

I am searching for a 2D physics engine to simulate gravity using images, preferably PNG images with transparency. So the engine will know how to calculate the collision base on the opaque parts of the image. I have only found Javascript engines that works with primitive shapes and basic HTML elements, but not with images.

Answer 1

One think you could do is compute the convex hull of your image (you can have a look here) and then use those hulls to compute collisions and so on (using GJK for example, you can find some great explanations here or here)

As noted by micnic, I guess you can indeed use Box2D.js and feed a b2PolygonShape why the non transparent pixels of your images (or you can compute their contours and use contours as input for the b2PolygonShape)