This is a copy of the source code for DOOM's executable, v1.10 (public release version). This source code was initially released under the DOOM license in 1997, but then dual licensed (DOOM/GPL) in 1997 to encourage transparency in the development of ports and extensions of the DOOM game engines. A copy of the source under the DOOM license may be obtained at id Software's FTP, or at one of its mirrors on /idgames in the /idstuff/source directory.
Credits:
Everyone who's contributed to the understanding and development of the DOOM source code, and Bernd Kreimeier for preparing the source for release.