SuiteSparse: a suite of sparse matrix packages by T. A. Davis et al. (This repository contains copies of the official releases.)
The VCGlib is a C++, templated, no dependency, library for manipulation, processing and cleaning of triangle meshes
Source code for pbrt, the renderer described in the third edition of "Physically Based Rendering: From Theory To Implementation", by Matt Pharr, Wenzel Jakob, and Greg Humphreys.