Angel is a 2D game prototyping engine based on OpenGL and C++. It was originally made by a group of employees at Electronic Arts Los Angeles for use in a GameJam they were planning for April of 2008. Angel provides many useful functions for prototyping gameplay, including simple physics, particles, text rendering, sound, input mappings, config files, pathfinding, and Python scripting.
SHTns is a high-performance Spherical Harmonic Transform library. It was designed for numerical simulation (fluid flows, mhd, etc.) in spherical geometries, but can be used for any kind of problem involving scalar or vector spherical harmonics. It is very fast, thanks to careful vectorization and runtime tuning. It supports multi-threaded transforms via OpenMP. It features scalar and vector transforms, synthesis and analysis, and flexible truncation and normalization. A Python interface is included.