page_title: Open-source video game
section_title: 3D games and source releases
hierarchical_section_title: Open-source video game / History / 3D games and source releases
caption_attribution_description: Screenshot of human base in game Tremulous attacked by dragoons
context_page_description: An open-source video game, or simply an open-source game, is a video game whose source code is open-source. They are often freely distributable and sometimes cross-platform compatible.
context_section_description: Proprietary games such as Doom and Descent brought in the age of three-dimensional games in the early to mid 1990s, and free games started to make the switch themselves. Tuxedo T. Penguin: A Quest for Herring by Steve Baker, a game featuring the Linux mascot Tux, was an early example of a three-dimensional free software game. He and his son Oliver would later create other popular 3D free games and clones such as TuxKart and contribute to those by other developers such as Tux Racer. The Genesis3D engine project, Crystal Space and Cube also spawned other 3D free software engines and games. FlightGear is another good example, especially noting that it is not a shooter engine but a flight simulator.
  id Software, an early entrant into commercial Linux gaming, would also prove to be an early supporter of free gaming when John D. Carmack released the source code for Wolfenstein 3D and Doom, first under a custom license and then later the GPL. This was followed by the release of Quake engine, id Tech 2, id Tech 3 and most recently id Tech 4. This led not only to source ports that allowed the playing of the non-free games based on these engines (plus fan added enhancements) on free engines and systems, but also to new free games such as Freedoom, Nexuiz/Xonotic, Tremulous, and OpenArena. Freeware games, such as CodeRED: Alien Arena, Warsow, World of Padman and Urban Terror, have also taken advantage of these free engines and sometimes have given code back to the community. id Tech 4 was released as free software, even amongst patent concerns from Creative Labs. Development and editing tools are also commonly released freely, such as GtkRadiant.
  id partners and related, such as Raven Software, Bungie and 3D Realms, as well as several of the developers who participated in the Humble Indie Bundle, have also released code and it is now accepted practice for some mainstream game developers to release legacy source code. Formerly proprietary games such as Jump 'n bump, Meritous, Warzone 2100, HoverRace and Abuse have even been entirely released freely, including multimedia assets and levels. Some games are mostly free software but contain some proprietary content such as the Cube sequel, Sauerbraten or the former Quake III Arena mod Smokin' Guns, but some developers desire and/or work on replacing these with free content. Primarily proprietary developers have also helped free gaming by creating free libraries. Loki Software helped create and maintain the Simple DirectMedia Layer and OpenAL libraries and Linux Game Publishing created and maintain the free network layer Grapple. LGP also avoids publishing games similar to popular free titles. Many libraries/infrastructures have been created without corporate assistance however, such as the online gaming system GGZ Gaming Zone. In addition, various game creators are free software such as the ZZT remake MegaZeux, versions of Game Editor, the Game Maker inspired G-Creator, Godot, Construct, and ZGameEditor.
caption: Tremulous
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