
like audio playing, network code, client/server, convex collision detection and a custom script language, the torque script, and much more stuff. It is based partly on the first half life code, and the second quake, though several years later, it started supporting custom shaders, and many other interesting features, i don't know if this would be present or not.
https://github.com/GarageGames/Torque3D
It is released under the MIT license.