libfixgl, is an implementation of the OpenGL standard for realtime 3D graphics, based on fixed point arithmetic. It is mainly targeted towards handheld consoles such as the GP2X, GP32, GBA, or other FPU-less embedded devices.
Fully customizable and configurable global illumination ray tracer written in C++. H-RT is a research project aimed at comparing popular and less popular light reflection models.
You can obtain the source code of H-RayTracer at (Mercurial repository):
https://bitbucket.org/bayger/hrt