Doom 3 source code released

id Software’s Doom 3 source code has finally been released to the masses, and you are able to download it from Github. The reason why this slightly modified code was delayed in its mass market release was due to a particular issue that did not play nice with the shading software used, where said shading software is owned by Creative. Over on Twitter, John Carmack mentioned that “this demonstrates the idiocy of the patent — the workaround added four lines of code and changed two” when addressing the effort required to rewrite the code.

It seems that the Depth Fail shading patent that caused the delay is owned by Creative, although colloquially, it has been called “Carmack’s reverse”. The source code note in the acknowledgement did mention that “the Doom 3 GPL source code release does not include functionality enabling rendering of stencil shadows via the ‘depth fail’ method, a functionality commonly known as ‘Carmack’s Reverse.” Bear in mind that the Github code will not hold any game data, but at least you know how the Doom 3 universe works now.