Atmos
Atmos is a simple physically based renderer with the help of PBRT. In 2016, a video demo and the Renderer itself, were as my graduation project from JiangNan University.
Sophia
Sophia is a real-time DirectX 11 renderer. It is not quite a rich graphics engine, only packages some low-level DirectX functions and contains some useful tools. But it is enough to implement some Real-Time algorithms more efficiently.
smallptCuda
A simple cuda version of smallpt with some memory optimization. See more optimization details on Shawnlu and Bingo's blog.
ofxTrianglular
Based on Jonathan Richard Shewchuk's triangle library. ofxTrianglular is an OpenFrameWorks addon for subdividing a complex 2d shape into triangles.