There was a nice reaction to my raytracing demo on reddit and I got great feedback. One redditor has been helping me optimize the codebase and we’ve open sourced our combined efforts. Here is a demo of the current build (NB: broken rendering in OS X). Much smoother.
The rendering is nearly fast enough for use in games. A simple 3D Asteroids isn’t out of the question.
If you would like to contribute to the project, it is hosted on github.