CG_GL engine is OpenGL API-based open source engine for creating and managing effects. The newest version of the engine adds features like movable and scalable portals (like in the “Portal” game) working with NVidia PhysX, improved bokeh depth of field, more realistic fog, particles, fake raytrace using cube maps and many improvements. It now works both on Windows and Linux. There is also simple game created using the engine.
Engine can be found at: http://tweety3d.no-ip.org