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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')."
Xonotic (successor to Nexuiz) is worth a look: http://www.xonotic.org/
I think that might actually have evolved from Quake 2 era code originally, or something crazy like that - it's a lot more advanced now.
UFO:AI uses the Quake 2 engine on some level as well I think: http://ufoai.ninex.info/wiki/index.php/News
In my experience Nexuiz and UFO:AI have both been quality Open Source games, although I think UFO:AI contains some media that are not categorised as fully Free in the strictest sense. Xonotic looks to be doing some cool new things and I hope that UFO:AI has also improved since I last played with it.
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)
It seems that the licensing is a mess.
The header in the source files state that the code is GPLv3 or any later version, with additional clauses added.
In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code. If not, please request a copy in writing from id Software at the address below.
However, it seems that it is only possible to apply these additional terms to GPL version 3 exactly (and not any later version):
2. Replacement of Section 16. Section 16 of the GPL shall be deleted in its entirety and replaced with the following:
These additional terms seem to be just disclaimers of liability and an indemnity clause, but it is entirely possible that they make the source GPL-incompatible, which, if true, would be a huge disappointment.
So not only is the license not self-consistent, it is likely also GPL-incompatible. The additional terms may further make the license non-free, and definitely non-DFSG-compliant. Thanks go to the corporate lawyers who have turned Carmack's good intentions into an abomination. I hope that they can re-release this under saner terms.
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
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.
IMHO the best thing about Doom 3 was that it lead to Quake 4, which is definitely one of my favorite single player games. Hell, Q4 is also one of the few games that had both worthwhile single player and multiplayer.
Check out Tremulous
Or World Of Padman, also (as far as I know) a derivative work from Quake3 sources, like Tremulous. (World Of Padman)
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.
Minor detail: id Software, as well as Bethesda Softworks, is owned by Zenimax Media. In other words, id and Bethesda are sister companies.
Now please mod me informative.
Dropbox drops it like it's hot.