Early id Software game engines open-sourced

Gaming giant id Software has extended its practice of releasing previous-generation game engines under open source licences, going right back to the founding of the company and the titles it released under the Softdisk label.

Now owned by Bethesda, many of the co-founders and early employees of id Software - including John Romero, John Carmack, Kevin Cloud, Jay Wilbur, Tom Hall and Adrian Carmack - got their start working for a disks-by-mail organisation called Softdisk. Their biggest success was a 3D ray-casting game engine created by John Carmack and used to create a range of games that would presage id Software's hit Wolfenstein 3D.

In recent years, id Software has got into the habit of releasing the source code to its game engines under the GNU Public Licence - allowing coders to take the engine and make their own games, or port existing games to new platforms, without having to pay royalties or suffer restrictions on the code's use. Its very early games, however, were created while under Softdisk's direct employ - meaning id Software has been previously unable to distribute the source code.

'Thanks to [current copyright holder] Flat Rock Software,' John Carmack wrote in a Twitter post late last week, 'the early code I wrote for Softdisk is going GPL.' The code itself is available on the company's official GitHub repository, with the sources of the Catacomb series - Catacomb, Catacomb II, Catacomb Abyss, Catacomb Armageddon, Catacomb 3D - and Hovertank 3D - currently available.

As with id Software's direct engine release, the source code does not come with the still-copyright game assets such as graphics and audio; in other words, you can't just clone the repository, compile and have ready-to-play versions of the games at your fingertips. The code does, however, provide an insight into the early careers of some of gaming's biggest names - and the potential for some clever hacks and mods to come.