Description: SmallUPBP : A (not too) small physically based volumetric renderer
SmallUPBP is a small physically based renderer that implements the unified points, beams and paths algorithm described in the paper
Unifying points, beams, and paths in volumetric light transport simulation Jaroslav Křivánek , Iliyan Georgiev , Toshiya Hachisuka , Petr Vévoda, Martin Šik , Derek Nowrouzezahrai , and Wojciech Jarosz ACM Transactions on Graphics 33(4) (SIGGRAPH 2014) BibTeX
as well as a number of other algorithms, notably including progressive photon mapping, (progressive) bidirectional photon mapping, bidirectional path tracing, vertex connection and merging, beam radiance estimate, and photon beams.