bulletphysics/bullet3 — pull request #297 by Orbots (2014-12-13 04:32:47+00:00)
Title: Convex hull fix

The GrahamScan2dConvexHull method has a couple of bugs that are fixed here.
* firstly the angles were not calculated robustly, especially if you consider vectors not co planar with the designated plane normal. This is fixed by using atan2 after the planar projection.

* next the method would terminate early and return a hull of only one point if the stack contained only 3 points that make a non-convex angle. This is fixed by pushing points onto the stack if it needed.