[tintin]

Sunflow seems dead.

Take a look at LuxRender. Source: http://www.luxrender.net/en_GB/source_code

[edit] also take a look at the forum: http://www.luxrender.net/forum/ There are a lot of nice projects related to LuxRender. From exporters to GPU rendering.

[dualogy]

Another good one, yeah. Basically I was just once again abusing HN as my personal bookmarking tool -- so that, when the time comes to learn from their open sources, I won't have a hard time remembering the name of the project.

Wow, LuxRender really does look so promising. Probably I can really skip Sunflow and dive right into Lux. 4-5 years in graphics algorithms is an eternity, after all (which is both wonderful and annoying)...

[Keyframe]

Also worth noting is PBRT: https://github.com/mmp/pbrt-v2 which is described in a book by Matt Pharr: http://www.pbrt.org/ It's basically a modern textbook on the subject. Or, if you prefer GPU, check out Arauna: http://igad.nhtv.nl/~bikker/