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Doom 3 Source Released
alteveer writes "Just like Quake 3 before it, the Doom 3 source code has been released to the public (minus rendering of stencil shadows via the 'depth fail' method, a functionality commonly known as 'Carmack's Reverse')."
It's funny you mention Modern Warfare 3 since that game's engine is based on id Tech 3, an engine id Software open sourced before, just like they are doing now with Tech 4. "The engine was first used for Call of Duty 2 in 2005 under a proprietary license of id Tech 3 created by id Software in 1999, as at this time, the engine was a heavily modified version of the Quake III engine. The engine did not have an official name until IGN was told at the E3 2009 by the studio that Call of Duty: Modern Warfare 2 would run on the "IW 4.0 engine". (http://en.wikipedia.org/wiki/IW_engine)
Here are a few link to lists that answer your question:
http://en.wikipedia.org/wiki/Id_Tech_3#Projects_based_on_the_GPL_source_release
http://en.wikipedia.org/wiki/Id_Tech_2#Games_based_on_the_GPL_source_release
This is hardly an authoritative source, but it does give some historical insight (from 2009) into why Carmack's Reverse had to be removed from the Doom 3 source release: http://newenthusiast.com/carmacks-reverse-still-an-issue-20090409489
This doesn't seem to be a problem since the base GPL v3 license explicitly allows replacement of Section 16:
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I've worked extensively with the Quake 1 and 2 sources (I ported them both to Pocket PC, which required rewriting a lot of the computationally expensive routines from floating point to fixed point math, as the ARM processors of that era did not have a FPU). I can say that no, you're not going to learn anything that way. The code has few if any comments at all, the routines are optimized, the data structures are optimized, tons of preprocessing of data happens both at the content level and during load time, plus any other trick Carmack could throw in there to increase performance. Unless you wanting to follow the path of execution as it relates to a specific data set or type of rendering, just to see the exact techniques used (obviously knowing specifically what you are looking for) then you're not going to learn that way.
Better known as 318230.
You can read the substituted implementation here: https://github.com/TTimo/doom3.gpl/blob/master/neo/renderer/tr_stencilshadow.cpp https://github.com/TTimo/doom3.gpl/blob/master/neo/renderer/tr_shadowbounds.cpp I won't pretend to fully understand it but it does seem to be an implementaion of shadow volumes.