Beginnings and early games '' Just as in
most other forms of software, free software was an unconscious occurrence during the creation of early computer games, particularly for earlier
Unix games. These are mostly arcade conversions, parlour games, and text adventures using libraries like
curses. A notable example of this is the "
BSD Games", a collection of
interactive fiction and other
text-mode titles. Game fan communities such as the
modding community do include
some aspects of free software, such as sharing mods across community sites, sometimes with free to use media made for the modification. With
the rise of
proprietary software in the mid to late 1980s, games became more and more proprietary. However, this
also led to the first deliberately free games such as
GNU Backgammon,
GNU Chess,
GNU Go, and
GNU Shogi of the
GNU Project established in 1983, part of whose goal is to create a complete free software system,
games included. More advanced free gaming projects emerged, such as
Moria and its descendant
Angband,
Hack and its derivatives
NetHack and ''
Slash'EM, in addition to Xtrek successor Netrek, variants of robots, and adventure game Dunnet, which has been included with GNU Emacs since 1994 among others. Still developed and played today, front-ends for frameworks such as X11, SDL, GTK and Qt, plus fuller featured variants such as Vulture's Eye have kept the games accessible. Roguelikes have continued to be produced, including Cataclysm: Dark Days Ahead, Tales of Maj'Eyal, HyperRogue, DRL, Egoboo, Shattered Pixel Dungeon, as well as Linley's Dungeon Crawl and its offspring Dungeon Crawl Stone Soup. The source code to the original Rogue'' was released under the
BSD license in 1986. As
PC gaming began to emerge in the late 1980s, free gaming also advanced. More complicated games utilizing the
X Window System for graphics started to appear, most beginning with the signature letter X. These included
Xconq and XPilot.
XBill is notable as one of the earliest free gaming titles to feature an activist theme of halting proprietary software adoption.
XEvil followed the development cycle of many early pieces of free software, having originally been developed as a university project on the
Project Athena network, although it was freeware for a while. The game was also one of the first free titles to feature
controversial subject matter such as
graphic violence and
drug use.
XTux was also an early
deathmatch game for Linux, featuring various
free software mascots, a theme that would continue to be revisited. ''
Rocks'n'Diamonds is another earlier free software game, and one of the first for Linux. Other games targeted or also supported the SVGAlib library allowing them to run without a windowing system, such as LinCity and
Maelstrom. The General Graphics Interface was also utilized, with games like Heroes
and Thrust.'' '' The
Freeciv project was started in 1995 and gave rise to another new style of free game development. Similar to the cooperative nature of the
Linux kernel development,
Freeciv was extended by many volunteers, rather than only one or two authors. It had started out as a small university student project but then branched out into its current form and is still being developed today.
Freeciv also proved to be one of the earliest very popular free software games, and was among the first to be included with Linux distributions, a system commonly known now as a source of peer review or selection of quality for free gaming projects. Magazines, news sources and websites have also started noting free games, often in listings.
Freeciv and other archetypes have led to the development of many other
clones of popular proprietary games.
Lincity was also started in 1995, despite there having been a
Unix version of its
namesake officially released by DUX Software in 1990. Beyond directly tying to the operating system, various free game development frameworks emerged starting with
Allegro in 1990,
SDL in 1998,
ClanLib in 1999,
OpenAL in 2000,
SFML in 2007, as well as SDL 2 and
Raylib in 2013. The
GNU Image Manipulation Program,
MyPaint,
Krita,
Inkscape,
Synfig,
Pencil2D,
Audacity,
Rosegarden,
OpenShot,
Kdenlive,
Pitivi,
Blender,
MakeHuman, and other applications have provided an entire open source toolchain for creative projects. Various free software
emulators and
compatibility layers have also been produced, such as
MAME and
MESS,
Mednafen,
higan,
Executor,
Darling,
lxrun,
Cygwin,
Dosbox,
ScummVM,
Anbox,
Wine and
Proton, allowing games to run in new environments (broadly targeted by the
RetroArch front-end).
3D games and source releases '' 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.
BZFlag pre-dates all of these, inspired by
Battlezone and started in 1992 and released in 1993.
FlightGear and YSFlight are additional examples of original 3D games, first started in 1997 and 1999 respectively, especially noting that they are not first-person shooters but
flight simulators;
Danger from the Deep meanwhile simulates
submarines. The
OpenGL specification provided a foundation for
hardware acceleration since 1992, primarily through the free
Mesa implementation since 1995, and later complimented by
Vulkan since 2016. The
Direct3D API has also been made available on free operating systems via
compatibility layers such as
WineD3D and
DXKV. The
Glide API was also made open source following the dissolution of
3dfx in 2002. The
Genesis3D engine project,
Crystal Space and
Cube also spawned other 3D free software engines and games, later joined by the likes of
Delta3D and
Dim3. Engines even exist for
high-level programming languages such as
Python and
Pascal. Several engines exist with rendering in
low-level C or
C++ with higher level scripting, such as
Panda3D for Python,
Basic4GL, and Cafu for Lua, or offering a variety of language binding options such as
Cocos3D,
Horde3D,
OGRE and the
Irrlicht Engine. The games
Yo Frankie! and
Sintel The Game were developed by the
Blender Foundation to showcase the abilities of the
Blender modelling tool and the erstwhile
Blender Game Engine, which has since been
forked as UPBGE. Since May 2023, the
GDevelop tool allows low to no code 3D game creation.
id Software, an
early entrant into commercial
Linux gaming, would also prove to be an
early supporter of free gaming when
John Carmack released the source code for
Wolfenstein 3D in 1995 and
Doom in 1997, first under a custom license and then later the
GNU General Public License (GPL) in 1999 (later termed
id Tech 1). This was followed by the release of
Quake engine in 1999, the
Quake II engine in 2001 (both known as
id Tech 2),
id Tech 3 in 2004 and most recently
id Tech 4 in 2011 (including the updated version from the
Doom 3: BFG Edition in 2012) before Carmack left id in 2013. id Tech 4 was released as free software, even amongst patent concerns from
Creative Labs over
Carmack's reverse, while the original
Doom source release shipped without music due to complications with the
Cygnus Studios developed DMX library (which lead to the
Linux version being selected for release). Carmack has continued to advise developers to be careful when depending on middleware, noting how it can limit the possibilities of later releasing source code.
Tim Sweeney has implied this issue has hindered potential releases of older
Unreal Engine source code. The
Godot,
Nebula Device,
Plasma,
Torque,
Bork3D,
Stride,
PlayCanvas,
Dagor Engine, and
Defold engines were also initially commercial and proprietary, while the
Open 3D Engine is derived from released code from
Amazon Lumberyard originally based on
CryEngine. '' 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 has also to the production of standalone free games. These include
Freedoom,
Blasphemer,
Open Quartz,
LibreQuake,
Nexuiz/
Xonotic,
Tremulous/
Unvanquished, and
OpenArena on
id Tech. Freeware games, such as
Harmony,
Alien Arena,
World of Padman, and
Urban Terror, have also taken advantage of these free engines and sometimes have given code back to the community. Development and editing tools are also commonly released freely, such as
GtkRadiant,
Qoole,
Doom Builder, and
LibreSprite. Released engines have also been used for
fangames such as
Sonic Robo Blast 2,
Wolfenstein: Blade of Agony,
Project Osiris,
ZBlood/Transfusion,
SUPERQOT, and ''
Slayer's Testament, and even commercial games such as Wrath: Aeon of Ruin, and Steel Storm, on the DarkPlaces engine, as well as titles by Blendo Games on the id Tech 2 and id Tech 4 engines. The game Ion Fury is built on the source available Build engine, and Excalibur: Morgana's Revenge'' on
Aleph One. '' id partners and related, such as
Raven Software,
Bungie,
Volition,
GarageGames,
Cyan Worlds, and
3D Realms, as well as Two Tribes,
Pangea Software, former developers from
Capstone Software,
Fields of Vision,
Virtual Design, and
Black Magic Software, and 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. Some games are mostly free software but contain proprietary content such as the
Cube sequel,
Sauerbraten (and
later forks, but not
Red Eclipse),
Warsow /
Warfork, or the former
id Tech mods
The Dark Mod and ''
Smokin' Guns, but some developers desire and/or work on replacing these with free content. Mods for originally proprietary games have gone standalone following the source code being released for their parent game, such as Nexuiz for Quake, Alien Arena for Quake II, and Urban Terror for Quake III, as well as Penumbra: Necrologue for Amnesia: The Dark Descent. Derivatives of released code or recreations have even been used for commercial re-releases of vintage games such as Wolfenstein 3D Classic for iOS, Abuse Classic for iPhone, Marathon 2: Durandal for Xbox Live Arcade, Duke Nukem and Duke Nukem II for the Evercade, and The Original Strife: Veteran Edition. Source code releases were used however for unauthorized versions of Lugaru and Abuse'' that were allowed onto the
App Store prior to takedown claims by the original developers. 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 maintained the free network layer
Grapple. LGP also avoided publishing games similar to popular free titles. Many libraries/infrastructures have been created without corporate assistance however, such as
Mumble voice over IP,
OBS Studio for
screencasting, and the
Lutris game manager.
Physics engines such as
Box2D,
Bullet,
Chipmunk,
Open Dynamics Engine,
Newton Game Dynamics and
PhysX have been made available as open source. In addition, various
game creation systems are free software such as versions of
Game Editor,
Adventure Game Studio,
OHRRPGCE,
Game-Maker, the engine behind
Stencyl, the original
Construct,
GDevelop and
Godot.
Rise in popularity and diversity '' Individuals and teams have continued creating many popular free software games, starting really in the late 1990s to the present day. Many of these are clones such as
Pingus (Lemmings),
Enigma (
Oxyd),
Beats of Rage (
Streets of Rage),
TetriNET (
Tetris),
Blobby Volley (
Arcade Volleyball), ''
Rocks'n'Diamonds (Boulder Dash), UltraStar (SingStar), OpenClonk (Clonk), Scorched 3D (Scorched Earth), Triplane Turmoil (Sopwith), Luanti (Minecraft),Zaz (Zuma), Pioneer and Oolite (Elite), SuperTux, Secret Maryo Chronicles and Mari0 (Super Mario Bros.), Frets on Fire (Guitar Hero), and StepMania (Dance Dance Revolution'').
Frozen Bubble, originally a clone of
Puzzle Bobble, has become a classic known for its addictive gameplay and winner of many
Linux Journal Reader's Choice Awards. These games and others have also helped expand the prevalent
Tux genre which started with titles and like
A Quest for Herring and are related to the activist content of games like
XBill. As well as ground up clones, open source
re-implementations of various proprietary games have become
increasingly common, which utilize the original game data. More original games such as the platformer
Teeworlds, puzzle games such as
kiki the nano bot and
The Powder Toy, and arcade games such as
C-Dogs,
Chromium B.S.U., have been able to carve out their own niches. A number of these games and those mentioned earlier and later in this section have received mainstream press coverage and commercial compilations, and have helped to establish free gaming as a moderately popular pastime, most
prominently among
Linux users and other free
Unix-like systems. As well, open source games have been made available for
Palm OS,
Android, and
iOS mobile devices. Additionally, these games provide options for a variety of alternative and
hobbyist systems. '' Strategy and simulation games have been a prevalent force in free software gaming, partly due to the lack of proprietary options for free software operating systems as compared to other genres like
first-person shooters and
role-playing games.
Xconq and
XBattle, and later
Freeciv and
Lincity, began the trend, and were followed by other clone titles like
FreeCol,
C-evo,
OpenCity,
TripleA,
Mindustry,
OpenRCT2,
OpenTTD,
Simutrans,
Tenés Empanadas Graciela,
Endgame: Singularity,
Thousand Parsec,
Unknown Horizons and
Widelands. The
Stratagus project began as an attempt to recreate the proprietary
Warcraft II engine, under the name FreeCraft.
Blizzard Entertainment sent a
cease and desist letter in 2003 over the use of the name "craft" in comparison to
Warcraft and
StarCraft. Though the earlier free software strategy game
CRAFT: The Vicious Vikings shared the name "craft" without controversy. With the new, legally inoffensive name Stratagus and the old FreeCraft assets renamed ''Aleona's Tales
, the team began work on a new strategy game called Bos Wars''. '' After the Stratagus example, other real-time strategy games were developed, such as
Globulation 2, which experiments with game management mechanics, the similarly experimental
Liquid War, the 3D project
0 A.D. (a former freeware project), and
Glest. One of the earliest was
RARS, which evolved following the principle of forking into
TORCS and then
Speed Dreams. Other racing games include versions of
Racer,
VDrift,
Rigs of Rods,
GLtron and
Armagetron Advanced, the
Mario Kart–inspired
SuperTuxKart,
Elasto Mania clone
X-Moto, sledding game
Extreme Tux Racer, and
Dust Racing 2D. ''
WorldForge,
Ryzom,
Crossfire, and
Solipsis are further examples of increasing diversification, offering free
massively multiplayer online role-playing game worlds. Single-player role-playing games are also available, such as
A Dark Room and GNU FreeDink. The rise of the
independent game development in the 2000s and 2010s was partly driven by the growing ecosystem of open-source libraries and engines; indie developers utilized the open-source ecosystem due to good
cross-platform capabilities and availability for limited financial burden. Educational languages such as
Snap! and
Scratch are also free software. Individual developers such as
Jason Rohrer, creator of
Passage and
One Hour One Life, and
Kenta Cho have embraced open source.
Greater organization '' Despite its initial roots as individual projects, the free software gaming scene has been becoming progressively more organized. The roots of this even go back as far as the games created for the GNU Project and to the original larger-scale free software projects like
Freeciv. Still, for the most part free game development had very little organization throughout its history. Popular games were generally separate efforts, except for instances of people working on them known for other projects such as Ingo Ruhnke (
Pingus), Bill Kendrick (
SuperTux) and Steve Baker (
TuxKart). Games were commonly found in directories such as
The Linux Game Tome and
Freshmeat and hosted on sites like
SourceForge and
GNU Savannah, but they were largely only ever brought together in the form of disorganized lists. Other projects and games existed purely on isolated personal or project websites, often unknown and ignored. The launch of the
GNOME and
KDE desktop projects in the late 1990s organized application and, to a certain extent, game development. Both attempts to create a more usable
Linux desktop attracted volunteers to make utilities to that end. These programs included games, mostly recreations of small games like
Minesweeper or
Solitaire that come with Microsoft Windows, arcade classics and the like, games from combined sets such as
Microsoft Entertainment Pack, and occasionally original ideas. The variety and number of these games, and other free games easily found in software repositories, have had GNOME or KDE-enabled Linux called a better option for
out of the box casual gaming than Microsoft Windows. They also provide games for other
Unix-like operating systems, such as
BSD and
Solaris. Many such games are packaged into kdegames and the erstwhile GNOME Games package. Although designed primarily for application development, the underlying
GTK and
Qt toolkits have also been used broadly for game development, as have
wxWidgets,
Tk, and
FLTK. The availability of
free game engines, such as
Stratagus,
Pygame, and
LÖVE, have also helped unify free software development by making the engine projects themselves hubs of activity for games that make use of them. '' The
Battle for Wesnoth project was started in 2003 and quickly became popular to both players and editors. It also showcased some new ideas when it came to free game development. Like
Freeciv before it, it utilized the efforts of the gaming and
free software community and their code, levels and artwork contributions but it also accepted storyline contributions and ideas for the game's entire
fictional universe. The game's canon is maintained through review and discussion over which submitted
campaigns become official, thus setting up a model for community input and organized results. This helped the game grow in scale and popularity to the point of being almost saga-like in scope. In addition, the project is worked on by many well-known free programmers, artists, designers and musicians such as the co-founder of the
Open Source Initiative Eric S. Raymond, and Linux kernel
hacker Rusty Russell.
Vega Strike has similarly allowed its community to expand the game and the surrounding lore while maintaining canon consistency. The
Wesnoth developers also worked on
Frogatto & Friends, which features a free engine but mostly proprietary game data.
Hubs and development teams '' The general lack of unity and organization has created and continues to generate some controversy among the free software community, with problems of "
reinventing the wheel" by making similar clones, games and multimedia resources being cited as a notable problem to free game development. This is especially taking up more notice as other problems are corrected, such as a lack of tools, libraries, artists and coders. A more central knowledge bank, texture library, and discussion area had been lacking. Traditionally free software video games were developed as individual projects, some small scale and others larger scale. Programmers and other developers did often work on other projects, but the whole system was very unlinked. More recently free software development teams have started appearing, groups that function like software companies and create multiple pieces of work. '' The Linux Game Tome "Game of the Month" team was an open group of game developers that revamp old free software games. Some examples include the transformation of
TuxKart into the more modern
SuperTuxKart, work on
Pingus and
SuperTux, and
Lincity-NG, an updated version of
Lincity with superior graphics.
Hard Vacuum assets with the
OpenRA engine.
PlayPower is a non-profit organization founded in 2008 designed to create free educational computer software for low income families in
India and other developing countries. The Tux4Kids initiative also maintains various educational games featuring the child-friendly Tux character such as
Tux Paint,
Tux, of Math Command,
Tux Typing and related efforts. The
GCompris suite is also available from
KDE. In recent years, content repositories such as
OpenGameArt.org,
Wikimedia Commons,
Openclipart, and
The Freesound Project have enabled developers to easily find appropriately-licensed content rather than relying on
programmer art. Such content is often under
Creative Commons licenses or those in the GNU GPL family, easily facilitating use by most free software projects. OpenGameArt.org is also affiliated with related websites such as Libregamewiki, and the FreeGameDev forums.
GitHub,
GitLab and
Gitea now host a significant number of free and open-source games. The
itch.io service is also a host for many open source games, and also features an open source client. The same is true for competitor
Game Jolt, and was also the case for former distributor
Desura. A number of open source games have even been made available on
Steam. Many free software games are also available from
Flathub and
Snap. ==See also==