OpenGL.org:

AA2K6 is the latest in a series of standalone games based on a classic Sci-Fi theme with a modern, updated visual experience. With 32 levels, five game modes, 5 mutators, enahnced bot AI, 9 characters, 8 weapons, the game has an endless supply of replayability. It uses the open source CRX v5.0 OpenGL API-based engine which adds light blooms, multitexture combine, reflective water, textured particles, stainmaps, 32 bit color, vertex lighting on models, shaders, fog, and more.