Cross platform Torque 3D game engine will be open sourced soon under MIT license. In a blog post, GarageGames announced that complete Torque 3D 1.2 source code, along with the four starting templates, will be made available in a GitHub repository.
One of the goals of GarageGames is to improve Mac and Linux support once the code is released. Check out a demo video of Torque 3D engine:
Thanks to mr.Ofen