Crystal Space is a free (LGPL) and portable 3D engine written in C++. It
supports: true six degree's of freedom, colored lighting, mipmapping,
portals, mirrors, alpha transparency, reflective surfaces, 3D sprites
(frame based or with skeletal animation), procedural textures,
radiosity, particle systems, halos, volumetric fog, scripting (using
Python or other languages), 8-bit, 16-bit, and 32-bit display support,
Direct3D under Windows, Glide and OpenGL on Windows, GNU/Linux, OS/2,
Macintosh, BeOS, ...