Blendo Games, an indie development team run by Brendon Chung and known for their surreal and highly experimental games has released the source code for their latest release, Quadrilateral Cowboy, under the GPL license.
This move will certainly help other independent developers interested in using the idTech 4 engine for their projects.
Excerpt from the Quadrilateral Cowboy F.A.Q.
What technology does Quadrilateral Cowboy use?
SDL2 integration was done by Aaron Melcher.
Where can I download the source code to Quadrilateral Cowboy?
Click here to download the source code (12mb).
Quadrilateral Cowboy uses the idTech 4 (Doom 3) engine. The source code is written in C++ and includes the solution files for Microsoft Visual C++ 2010.
The source code is released under the GPL license.
Source: Quadrilateral Cowboy F.A.Q.