No need for mentors, the rendering code (Time/light.cxx and Viewer/renderer.cxx) is interesting enough to follow. Some comments are a bit misleading, but the code is written very cleanly. So the bus might be able to run over people, but the clean and functioning code - the bedrock of the project - will remain clean and functional.
It's quite interesting to just dive into the FlightGear renderer code and explore. I know too that I could get my basic questions answered on the devel mailing list, as I'm sure Curt and James knows the overall design of the code. But I find it more fun to just delete or comment out individual parts and see what happens when you start up FG You learn by seeing a lot of funkiness and weirdness. I might consider adding to the wiki, but this seems like a moving target and the wiki article would become out of date quite quickly. For example I might come up with some changes that would disrupt such an article. It'd be of greater benefit to document the code itself using detailed comments. But I'll see what I can do with The_FlightGear_Rendering_Pipeline.
Regards,
Edward