Following slight rewrites from id Software's John Carmack to avoid potential patent infringement, the source code behind Doom 3 was made public on Tuesday for open source use.

The source does not contain any game data, which is still covered by the original EULA.

The source also does not include functionality enabling rendering of stencil shadows via the "depth field" method (commonly called "Carmack's Reverse"), which lawyers from parent company Zenimax said might infringe on a patent for a Creative Labs 3D shading technique.

According to Carmack, minor tweaks were made to the code to avoid any infringement: he recently tweeted that the workaround "added four lines of code and changed two."

The source is available now on GitHub.