mrdoob/three.js — pull request #2866 by bhouston (2012-12-31 13:36:40+00:00)
Title: Fix ArrowHelper so it can point downwards (+ some optimization)

While debugging normals during geometry creation I noticed that ArrowHelper wasn't able to point downwards (0,-1,0). This PR fixes this issue and also optimizes ArrowHelper based on a suggestions from @WestLangley here: https://github.com/mrdoob/three.js/pull/2845#issuecomment-11725063

Tested lights in /editor/index.html and the /examples that referenced ArrowHelper directly. Seems to all works.