View source for Source

{{primary sources|date=June 2017}}
{{unreliable sources|date=June 2017}}
{{Use mdy dates|date=July 2015}}
{{Infobox software
| name = Source
| logo = File:Source engine logo and wordmark.svg
| logo caption = 
| screenshot = 
| caption = 
| developer = [[Valve]]
| latest release version = 
| latest release date = 
| programming language = [[C++]]
| platform = 
| genre = [[Game engine]]
| license = [[Proprietary software|Proprietary]]
}}
'''Source''' is a [[Game engine|3D video game engine]] developed by [[Valve Corporation]]. It debuted as the successor to [[GoldSrc]] with ''[[Counter-Strike: Source]]'' in June 2004, followed shortly by ''[[Half-Life 2]]'' in November, and has been in active development since. Source does not have a concise [[version numbering]] scheme; instead, it is designed in constant incremental updates.<ref name="develop-11" /> The successor, Source 2, was officially announced in March 2015, with the first game to use it being ''[[Dota 2]]'', which was ported over from Source later that year.

==History==
Source distantly originates from the [[GoldSrc]] engine, itself a heavily modified version of [[John Carmack]]'s [[Quake engine|''Quake'' engine]]. Carmack commented on his [[blog]] in 2004 that "there are still bits of early ''Quake'' code in ''Half-Life 2''".<ref>{{cite web|url=http://www.armadilloaerospace.com/n.x/johnc/recent%20updates/archive?news_id=290|date=December 31, 2004|work=John Carmack's Blog|title=Welcome, Q3 source, Graphics|deadurl=yes|archiveurl=https://web.archive.org/web/20060517235354/http://www.armadilloaerospace.com/n.x/johnc/recent%20updates/archive?news_id=290|archivedate=May 17, 2006|df=mdy-all}}</ref>  Valve employee Erik Johnson explained the engine's [[nomenclature]] on the Valve Developer Community:<ref name="goldsrc-src-quote">{{cite web|url=https://developer.valvesoftware.com/w/index.php?title=User_talk:Erik_Johnson&oldid=10088#GoldSource|title=Talk:Erik Johnson|work=Valve Developer Community|last=Johnson|first=Erik|date=September 1, 2005|accessdate=August 15, 2007|deadurl=no|archiveurl=https://web.archive.org/web/20120213011333/https://developer.valvesoftware.com/w/index.php?title=User_talk:Erik_Johnson&oldid=10088#GoldSource|archivedate=February 13, 2012|df=mdy-all}}</ref>

{{Quotation|When we were getting very close to releasing ''[[Half-Life (video game)|Half-Life]]'' (less than a week or so), we found there were already some projects that we needed to start working on, but we couldn't risk checking in code to the shipping version of the game. At that point we [[Fork (software development)|forked]] off the code in [[Microsoft Visual SourceSafe|VSS]] to be both <code>/$Goldsrc</code> and <code>/$Src</code>. Over the next few years, we used these terms internally as "Goldsource" and "Source". At least initially, the Goldsrc branch of code referred to the codebase that was [[Software release life cycle#Release|currently released]], and Src referred to the next set of more risky technology that we were working on. When it came down to show ''[[Half-Life 2]]'' for the first time at [[Electronic Entertainment Expo|E3]], it was part of our internal communication to refer to the "Source" engine vs. the "Goldsource" engine, and the name stuck.}}

Source was developed part-by-part from this fork onwards, slowly replacing GoldSrc in Valve's internal projects<ref>{{cite book|last=Hodgson|first=David|year=2004|title=Half-Life 2: Raising the Bar|publisher=[[Prima Games]]|isbn=0-7615-4364-3}}</ref> and, in part, explaining the reasons behind its unusually modular nature. Valve's development of Source since has been a mixture of licensed [[middleware]] and in-house-developed code. Among others, Source uses [[Bink Video]] for video playback.<ref>{{Cite news|url = http://pc.gamespy.com/pc/counter-strike-remake-source-engine-powered/531716p1.html|title = Counter-Strike: Source - Full-Screen E3 2004 Presentation|last = O'Donnell|first = Ryan|date = Jul 19, 2004|work = GameSpy|access-date = Apr 20, 2015|via = |deadurl = no|archiveurl = https://web.archive.org/web/20160304113927/http://pc.gamespy.com/pc/counter-strike-remake-source-engine-powered/531716p1.html|archivedate = March 4, 2016|df = mdy-all}}</ref>

===Modularity and notable upgrades===
Source was created to evolve incrementally with new technology, as opposed to the [[backward compatibility]]-breaking "version jumps" of its competitors. Different systems within Source are represented by separate modules which can be updated independently. With [[Steam (software)|Steam]], Valve can distribute these updates automatically among its many users. In practice, however, there have been occasional breaks in this chain of compatibility. The release of ''[[Half-Life 2: Episode One]]'' and ''[[The Orange Box]]'' both introduced new versions of the engine that could not be used to run older games or [[Mod (video gaming)|mods]] without the developers performing upgrades to code and, in some cases, content.<ref>{{Cite web|url=http://www.planetphillip.com/posts/new-update-breaking-new-and-old-mods/|title=New Update Breaking New and Old Mods?|publisher=PlanetPhillip|accessdate=October 17, 2014|deadurl=no|archiveurl=https://web.archive.org/web/20141021132929/http://www.planetphillip.com/posts/new-update-breaking-new-and-old-mods/|archivedate=October 21, 2014|df=mdy-all}}</ref> Both cases required markedly less work to update its version than competing engines. This was demonstrated in 2010, when Valve updated all of their core Source games to the latest engine build.{{Citation needed|date=December 2016}}

Since Source engine's release in 2004, the following major architectural changes have been made:

==== Source 2006 ====
[[File:Half-Life 2 Episode One Citadel Base.jpg|thumb|upright=1.2|A screenshot of ''[[Half-Life 2: Episode One]]''. The [[high dynamic range rendering]] and [[Phong shading]] effects are evident.]]

The Source 2006 branch was the term used for Valve's games using technology that culminated with the release of ''Half-Life 2: Episode One''. [[High-dynamic-range rendering|HDR rendering]] and [[color correction]] were first implemented in 2005 using ''[[Day of Defeat: Source]]'', which required the engine's shaders to be rewritten.<ref name="hdr_shaders">{{cite video game|title=[[Half-Life 2: Lost Coast]]|developer=[[Valve Corporation]] |year=2005|platform=PC|quote='''Chris Green''': The Source engine supports a wide variety of shaders. The refraction shader on the window here requires us to copy the scene to a texture, refract it, and then apply it the window surface. To fully support HDR, every shader in the engine needed to be updated, so this refraction shader was improved to the support the full range of contrast.}}</ref> The former, along with developer commentary tracks, were showcased in ''[[Half-Life 2: Lost Coast]]''.  ''Episode One'' introduced [[Phong shading]] and other smaller features. Since the transition to Steam Pipe, this branch was made deprecated and is now used for backward compatibility with older mods.{{Citation needed|date=December 2016}} [[Image-based modeling and rendering|Image-based rendering]] technology had been in development for ''[[Half-Life 2]]'',<ref name="driverheaven-2003">{{cite web | url=http://www.driverheaven.net/dhinterviews/gabenewell/ | title=Interview with Gabe Newell | work=DriverHeaven.net | accessdate=November 21, 2009 | deadurl=yes | archiveurl=https://web.archive.org/web/20090628171827/http://www.driverheaven.net/dhinterviews/gabenewell/ | archivedate=June 28, 2009 | df=mdy-all }}</ref> but was cut from the engine before its release. It was mentioned again by [[Gabe Newell]] in 2006 as a piece of technology he would like to add to Source to implement support for much larger scenes that are impossible with strictly [[Polygon (computer graphics)|polygonal]] objects.<ref name="1up-valveweek">{{cite web|url=http://valve.1up.com/|work=[[1UP.com]]|title=Valve Week|accessdate=July 14, 2006|deadurl=no|archiveurl=https://web.archive.org/web/20060713230939/http://valve.1up.com/|archivedate=July 13, 2006|df=mdy-all}}</ref>

==== Source 2007 ====
The Source 2007 branch represented a full upgrade of the Source engine for the release of ''The Orange Box''. An artist-driven, threaded [[particle system]] replaced previously [[hard-coded]] effects for all of the games within.{{cn|date=May 2018}} An in-[[Process (computing)|process]] tools framework was created to support it, which also supported the initial builds of [[Source Filmmaker]]. In addition, the facial animation system was made hardware-accelerated on modern video cards for "feature film and broadcast television" quality.<ref name="steamnews_meetheavy">{{cite web|url=http://store.steampowered.com/news/1039/|title=Face-to-Face with TF2's Heavy|work=Steam news|date=May 14, 2007|accessdate=April 25, 2010|deadurl=no|archiveurl=https://web.archive.org/web/20090508071620/http://store.steampowered.com/news/1039/|archivedate=May 8, 2009|df=mdy-all}}</ref> The release of ''The Orange Box'' on multiple platforms allowed for a large [[code refactoring]], which let the Source engine take advantage of multiple CPU cores.<ref name="PCZone">{{cite web|url=http://www.computerandvideogames.com/article.php?id=145846|title=Interview: Gabe Newell|accessdate=September 20, 2006|publisher=[[PC Zone]]|date=September 11, 2006|deadurl=no|archiveurl=https://web.archive.org/web/20120305153907/http://www.computerandvideogames.com/145846/interviews/gabe-newell/|archivedate=March 5, 2012|df=mdy-all}}</ref> However, support on the PC was experimental and unstable<ref name="steam-forum-mat_queue_mode">{{cite web|url=http://forums.steampowered.com/forums/showpost.php?p=8413873&postcount=92|title=Dual Core Performance|date=October 11, 2008|accessdate=December 23, 2008|deadurl=no|archiveurl=https://web.archive.org/web/20120314103803/http://forums.steampowered.com/forums/showpost.php?p=8413873&postcount=92|archivedate=March 14, 2012|df=mdy-all}}</ref> until the release of ''Left 4 Dead''.<ref name="left-4-dead-multicore">{{cite web|url=http://www.pcgameshardware.de/aid,643448/Interview/PCGH_interview_about_Left_4_Dead_part_2/?page=2|title=PCGH interview about Left 4 Dead, part 2|first=Doug|last=Lombardi|others=Interviewer: Frank Stöwer|date=May 13, 2008|accessdate=December 23, 2008}}</ref> Multiprocessor support was later backported to ''Team Fortress 2'' and ''Day of Defeat: Source''.<ref>{{cite web|url=http://www.shacknews.com/onearticle.x/57728|title=Team Fortress 2 Update Adds Multicore Rendering|first=Breckon|last=Nick|date=March 18, 2008|accessdate=August 19, 2009|deadurl=no|archiveurl=https://web.archive.org/web/20090616033113/http://www.shacknews.com/onearticle.x/57728|archivedate=June 16, 2009|df=mdy-all}}</ref> Valve created the [[Xbox 360]] release of ''The Orange Box'' in-house, and support for the console is fully integrated into the main engine codeline. It includes asset converters, cross-platform play and [[Xbox Live]] integration.<ref name="official_consoles">{{cite web|url=http://source.valvesoftware.com/console.php|title=Source - Console Support|publisher=Valve|accessdate=August 8, 2009|deadurl=yes|archiveurl=https://web.archive.org/web/20090813213319/http://source.valvesoftware.com/console.php|archivedate=August 13, 2009|df=mdy-all}}</ref> Program code can be ported from PC to Xbox 360 simply by recompiling it.<ref name="joystiq_source360">{{cite web|url=http://www.joystiq.com/2006/10/17/joystiq-interviews-doug-lombardi-about-xbox-360-source/|title=Joystiq interviews Doug Lombardi about Xbox 360 Source|publisher=Joystiq|date=October 17, 2006|accessdate=August 8, 2009|deadurl=no|archiveurl=https://web.archive.org/web/20090922165323/http://www.joystiq.com/2006/10/17/joystiq-interviews-doug-lombardi-about-xbox-360-source/|archivedate=September 22, 2009|df=mdy-all}}</ref> The [[PlayStation 3]] release was outsourced to Electronic Arts, and was plagued with issues throughout the process. [[Gabe Newell]] cited these issues when criticizing the console during the release of ''The Orange Box''.<ref>{{Cite news|url = https://www.engadget.com/2007/10/11/gabe-newell-calls-ps3-waste-of-everybodys-time/|title = Gabe Newell calls PS3 'waste of everybody's time'|last = Yoon|first = Andrew|date = October 11, 2007|work = Engadget|access-date = April 20, 2015|via = |deadurl = no|archiveurl = https://web.archive.org/web/20150703175918/http://www.engadget.com/2007/10/11/gabe-newell-calls-ps3-waste-of-everybodys-time/|archivedate = July 3, 2015|df = mdy-all}}</ref>

==== ''Left 4 Dead'' branch ====
The Left 4 Dead branch was a complete overhaul of the Source engine through the development of the [[Left 4 Dead (series)|''Left 4 Dead'' series]]. Multiprocessor support was further expanded, allowing for features like split screen multiplayer, additional post-processing effects, event scripting with [[Squirrel (programming language)|Squirrel]], and the highly-dynamic [[Left 4 Dead#AI Director|AI Director]]. The menu interface was re-implemented with a new layout designed to be more console-oriented. This branch later fueled the releases of ''[[Alien Swarm]]'' and ''[[Portal 2]]'', the former released with source code outlining many of the changes made since the branch began. ''Portal 2'', in addition, served as the result of Valve taking the problem of porting to PlayStation 3 in-house, and in combination with [[Steam (software)#Developer features|Steamworks]] integration creating what they called "the best console version of the game".<ref>{{cite web|title=Portal 2: Pretty Much Every PS3 Question Answered (And That Cake Thing, Too)|url=http://blog.eu.playstation.com/2011/04/14/portal-2-pretty-much-every-ps3-question-answered-and-that-cake-thing-too/|publisher=[[Sony Computer Entertainment America]]|date=April 14, 2011|deadurl=no|archiveurl=http://archive.wikiwix.com/cache/20110902205417/http://blog.eu.playstation.com/2011/04/14/portal-2-pretty-much-every-ps3-question-answered-and-that-cake-thing-too/|archivedate=September 2, 2011|df=mdy-all}}</ref>

==== [[OS X]], [[Linux]], and [[Android (operating system)|Android]] support ====
In April 2010, Valve released all of their major Source games on OS X, coinciding with the release of the Steam client on the same platform. Valve announced that all their future games will be released simultaneously for Windows and Mac.<ref>{{cite web|url=http://store.steampowered.com/news/3569/|title=Valve to Deliver Steam & Source on the Mac|publisher=Valve|date=March 8, 2010|accessdate=March 8, 2010|deadurl=no|archiveurl=https://web.archive.org/web/20130826011221/http://store.steampowered.com/news/3569/|archivedate=August 26, 2013|df=mdy-all}}</ref><ref>{{cite web|url=http://kotaku.com/5488375/left-4-dead-2-team-fortress-2-portal-and-steam-coming-to-mac-in-april|title=Left 4 Dead 2, Team Fortress 2, Portal and Steam Coming to Mac in April|publisher=Kotaku|date=March 8, 2010|accessdate=March 8, 2010|deadurl=no|archiveurl=https://web.archive.org/web/20111218172810/http://kotaku.com/5488375/left-4-dead-2-team-fortress-2-portal-and-steam-coming-to-mac-in-april|archivedate=December 18, 2011|df=mdy-all}}</ref> The first of Valve's games to support Linux was ''[[Team Fortress 2]]'', the port released in October 2012 along with the closed beta of the Linux version of Steam. Both the OS X and Linux ports of the engine take advantage of [[OpenGL]] and are powered by [[Simple DirectMedia Layer|SDL]].<ref>{{Cite web|title = Simple DirectMedia Layer - Homepage|url = https://www.libsdl.org/|accessdate = April 21, 2015|deadurl = no|archiveurl = https://web.archive.org/web/20180421220935/http://libsdl.org/|archivedate = April 21, 2018|df = mdy-all}}</ref> During the process of porting, Valve rearranged most of the games released up to ''The Orange Box'' into separate, but parallel "singleplayer" and "multiplayer" branches. The game code to these branches was made public to mod developers in 2013, and they serve as the current stable release of Source designated for mods. Support for Valve's internal Steam Pipe distribution system as well as the [[Oculus Rift]] are included.<ref>{{Cite web|title = News - Source SDK 2013 Release|url = http://store.steampowered.com/news/10962/|website = Steam|accessdate = April 21, 2015|deadurl = no|archiveurl = https://web.archive.org/web/20150408214515/http://store.steampowered.com/news/10962/|archivedate = April 8, 2015|df = mdy-all}}</ref> In May 2014, [[Nvidia]] released ports of ''Portal'' and ''Half-Life 2'' to their [[Tegra 4]]-based Android [[handheld game console]] [[Nvidia Shield]].<ref>{{cite web|url=http://blogs.nvidia.com/blog/2014/05/12/half-life-2-portal-shield/|title=The Greatest PC Games of All-Time – ‘Half-Life 2′ and ‘Portal’ – Now Available on SHIELD|publisher=Nvidia|date=May 12, 2014|accessdate=May 12, 2014|deadurl=no|archiveurl=http://archive.wikiwix.com/cache/20140513215833/http://blogs.nvidia.com/blog/2014/05/12/half-life-2-portal-shield/|archivedate=May 13, 2014|df=mdy-all}}</ref>

=== Source 2 ===
As far back as May 2011, one of Valve's largest projects has been the development of new content authoring tools for Source.<ref name="develop-11">{{cite web|last=Crossley|first=Rob|title=Valve on Source and studio culture|url=http://www.develop-online.net/features/1191/Valve-on-Source-and-studio-culture|publisher=Develop Magazine|accessdate=August 14, 2011|date=May 12, 2011|quote=We have as many people working on our tools as we have working on a single project. So, about twenty to thirty core people.|deadurl=yes|archiveurl=https://web.archive.org/web/20110813024757/http://www.develop-online.net/features/1191/Valve-on-Source-and-studio-culture|archivedate=August 13, 2011|df=mdy-all}}</ref> These would replace the current outdated tools, allowing content to be created faster and more efficiently. Newell has described the creation of content with the engine's current toolset as "very painful" and "sluggish".<ref>{{cite web|title=Steamcast #47|url=http://www.thesteamcast.com/episodes/47/|publisher=Steamcast|accessdate=August 14, 2011|date=February 9, 2011|quote=Oh yeah, we're spending a tremendous amount of time on tools right now. So, our current tools are... very painful, so we probably are spending more time on tools development now than anything else and when we’re ready to ship those I think everybody's life will get a lot better. Just way too hard to develop content right now, both for ourselves and for third parties so we’re going to make enormously easier and simplify that process a lot.|deadurl=yes|archiveurl=https://web.archive.org/web/20110818033018/http://www.thesteamcast.com/episodes/47/|archivedate=August 18, 2011|df=mdy-all}}</ref> Valve officially announced the engine at the [[Game Developers Conference]] in March 2015, also stating that it would be free to use for developers, with support for the [[Vulkan (API)|Vulkan graphical API]].<ref>{{cite web|url=http://www.polygon.com/2015/3/3/8145273/valve-source-2-announcement-free-developers|title=Valve announces Source 2 engine, free for developers|last=Kollar|first=Philip|date=March 3, 2015|accessdate=March 3, 2015|deadurl=no|archiveurl=https://web.archive.org/web/20150305093315/http://www.polygon.com/2015/3/3/8145273/valve-source-2-announcement-free-developers|archivedate=March 5, 2015|df=mdy-all}}</ref><ref>{{cite web|last1=Mahardy|first1=Mike|title=GDC 2015: Valve Announces Source 2 Engine|url=http://www.ign.com/articles/2015/03/04/gdc-2015-valve-announces-source-2-engine|accessdate=March 3, 2015|website=[[IGN]]|date=March 3, 2015|deadurl=no|archiveurl=https://web.archive.org/web/20150304021002/http://www.ign.com/articles/2015/03/04/gdc-2015-valve-announces-source-2-engine|archivedate=March 4, 2015|df=mdy-all}}</ref> In addition, Valve confirmed that it would be using a new in-house [[physics engine]] named Rubikon.<ref name=":0">{{Cite web|url = http://media.steampowered.com/apps/valve/2015/Migdalskiy_Sergiy_Physics_Optimization_Strategies.pdf|title = Physics for Game Developers: Physics Optimization Strategies|date = March 2015|accessdate = October 2, 2015|website = |publisher = [[Game Developers Conference]]|last = Migdalskiy|first = Sergiy|deadurl = no|archiveurl = https://web.archive.org/web/20160304061355/http://media.steampowered.com/apps/valve/2015/Migdalskiy_Sergiy_Physics_Optimization_Strategies.pdf|archivedate = March 4, 2016|df = mdy-all}}</ref> In 2015, ''[[Dota 2]]'' was ported over to Source 2 in an update called ''[[Dota 2 Reborn]]'', making it the first game to use the engine.<ref>{{cite web |last1=Macy |first1=Seth |title=Dota 2 Now Valve's First Ever Source 2 Game |url=http://www.ign.com/articles/2015/09/09/dota-2-now-valves-first-ever-source-2-game |website=IGN |accessdate=September 9, 2015 |deadurl=no |archiveurl=https://web.archive.org/web/20150910075128/http://www.ign.com/articles/2015/09/09/dota-2-now-valves-first-ever-source-2-game |archivedate=September 10, 2015 |df=mdy-all }}</ref><ref>{{cite magazine |last=Livingston |first=Christopher |url=http://www.pcgamer.com/valve-announces-dota-2-reborn-new-engine-coming/ |title=Valve announces Dota 2 Reborn, new engine coming |date=June 12, 2015 |magazine=[[PC Gamer]] |accessdate=June 13, 2015 |deadurl=no |archiveurl=https://web.archive.org/web/20150615040444/http://www.pcgamer.com/valve-announces-dota-2-reborn-new-engine-coming/ |archivedate=June 15, 2015 |df=mdy-all }}</ref><ref>{{cite web |last1=Martin |first1=Michael |title=Valve Announces Dota 2 Reborn |url=http://www.ign.com/articles/2015/06/13/valve-announces-dota-2-reborn-open-beta-coming-next-week |website=IGN |accessdate=July 10, 2016 |deadurl=no |archiveurl=https://web.archive.org/web/20160629144536/http://www.ign.com/articles/2015/06/13/valve-announces-dota-2-reborn-open-beta-coming-next-week |archivedate=June 29, 2016 |df=mdy-all }}</ref> The engine has since been used for ''[[Artifact (video game)|Artifact]]'' and ''[[Dota Underlords]]'', with a version of the engine that runs on [[Android (operating system)|Android]] and [[iOS]] devices.<ref>{{cite web | url = https://www.pcgamesn.com/artifact/artifact-source-2-ios-android | title = Artifact will use Source 2, bringing the engine to iOS and Android | first = Dustin | last = Bailey | date = March 8, 2018 | accessdate = March 8, 2018 | work = [[PCGamesN]] | deadurl = no | archiveurl = https://web.archive.org/web/20180309192121/https://www.pcgamesn.com/artifact/artifact-source-2-ios-android | archivedate = March 9, 2018 | df = mdy-all }}</ref>

== Tools and resources ==

===Source SDK===
[[File:Source SDK Launcher.jpg|thumb|The launcher menu for Source SDK]]
'''Source SDK''' is the [[software development kit]] for the Source engine, and contains many of the tools used by Valve to develop assets for their games. It comes with several command-line programs designed for special functions within the asset pipeline, as well as a few GUI-based programs designed for handling more complex functions. Source SDK was launched as a free standalone toolset through Steam, and required a Source game to be purchased on the same account. Since the release of ''Left 4 Dead'' in late 2008, Valve began releasing "Authoring Tools" for individual games, which constitute the same programs adapted for each game's engine build. After ''Team Fortress 2'' became free-to-play, Source SDK was effectively made open to all Steam users. When some Source games were updated to Source 2013, the older Source SDKs were phased out. The three applications mentioned below are now included in the install of each game.

There are three applications packaged in the Source SDK: Hammer Editor, Model Viewer, and Face Poser. Hammer Editor, the engine's official [[level editor]], uses rendering and compiling tools included in the SDK to create maps using the [[binary space partitioning]] (BSP) method. The tool was originally known as Worldcraft and was developed independently by Ben Morris before Valve acquired it.<ref>{{cite web|accessdate=May 12, 2010|url=http://www.bluesnews.com/pressreleases/WC16release.doc|title=Valve Press Release|publisher=Valve|deadurl=no|archiveurl=https://web.archive.org/web/20110610164022/http://www.bluesnews.com/pressreleases/WC16release.doc|archivedate=June 10, 2011|df=mdy-all}}</ref> The Model Viewer is a program that allows users to view models and can be used for a variety of different purposes, including development. Developers may use the program to view models and their corresponding animations, attachment points, bones, and so on. Face Poser is the tool used to access facial animations and choreography systems.  This tool allows one to edit [[Computer facial animation|facial expressions]], gestures and movements for characters, [[Lip-syncing#In video games|lip sync]] speech, and sequence expressions and other acting cues and preview what the scene will look like in the game engine.

=== Source Dedicated Server ===
The '''Source Dedicated Server''' or '''SRCDS''' is a standalone launcher for the Source engine that runs multiplayer game sessions without requiring a client. It can be launched through Windows or Linux, and can allow for custom levels and assets. Most third-party servers additionally run [[Metamod|Metamod:Source]] and SourceMod, which together provide a framework on top of SRCDS for custom modification of gameplay on existing titles.<ref>{{cite web|url=http://www.sourcemm.net/|title=MetaMod:S|deadurl=no|archiveurl=https://web.archive.org/web/20140701222549/http://www.sourcemm.net/|archivedate=July 1, 2014|df=mdy-all}}</ref><ref>{{cite web|url=http://www.sourcemod.net/|title=SourceMod|deadurl=no|archiveurl=https://web.archive.org/web/20140601222846/http://www.sourcemod.net/|archivedate=June 1, 2014|df=mdy-all}}</ref>

===Source Filmmaker===
{{Main|Source Filmmaker}}
The Source Filmmaker (SFM) is a video capture and editing application that works from within the Source engine.<ref name=sfm_home>{{cite web|url=http://www.sourcefilmmaker.com|title=Source Filmmaker|work=Source Filmmaker|accessdate=March 31, 2013|deadurl=no|archiveurl=https://web.archive.org/web/20130402181751/http://sourcefilmmaker.com/|archivedate=April 2, 2013|df=mdy-all}}</ref> Developed by Valve, the tool was originally used to create movies for ''Day of Defeat: Source'', but is more associated with ''Team Fortress 2''. Today, it is open for public use and downloadable via the [[Steam (software)|Steam]] client.

===Destinations Workshop Tools===
In June 2016, Valve released the Destinations Workshop Tools, a set of free [[virtual reality]] (VR) creation tools running using the Source 2 SDK.<ref>{{cite web|last1=Crecente|first1=Brian|title=Valve rolls out free VR creation tool for new destinations workshop|url=http://www.polygon.com/2016/6/8/11868324/valve-rolls-out-free-vr-creation-tool-for-new-workshop|website=Polygon|accessdate=9 June 2016|deadurl=no|archiveurl=https://web.archive.org/web/20160609045739/http://www.polygon.com/2016/6/8/11868324/valve-rolls-out-free-vr-creation-tool-for-new-workshop|archivedate=June 9, 2016|df=mdy-all}}</ref>

===Valve Developer Community===
In June 2005, Valve opened the Valve Developer Community (VDC) [[wiki]].{{cn|date=April 2018}} VDC replaced Valve's static Source SDK documentation with a full [[MediaWiki]]-powered community site; within a matter of days Valve reported that "the number of useful articles nearly doubled". These new articles covered the previously undocumented ''[[Counter-Strike: Source]]'' [[Video game bot|bot]], Valve's [[non-player character]] AI, advice for mod teams on setting up [[source control]], and other articles.

===Academic papers===
Valve staff occasionally produce professional and/or academic papers for various events and publications, including [[SIGGRAPH]], [[Game Developer (magazine)|Game Developer Magazine]] and [[Game Developers Conference]], explaining various aspects of Source engine's development.<ref name="Valve Publications">{{cite web | url=http://www.valvesoftware.com/company/publications.html | title=Valve Publications | accessdate=September 25, 2013 | deadurl=no | archiveurl=https://web.archive.org/web/20130921181832/http://valvesoftware.com/company/publications.html | archivedate=September 21, 2013 | df=mdy-all }}</ref>

==Games==

===Source===
====Valve games====
* ''[[Half-Life 2]]'' (2004)
* ''[[Half-Life 2: Deathmatch]]'' (2004)
* ''[[Half-Life: Source]]'' (2004)
* ''[[Counter-Strike: Source]]'' (2004)
* ''[[Day of Defeat: Source]]'' (2005)
* ''[[Half-Life 2: Lost Coast]]'' (2005)
* ''[[Half-Life Deathmatch: Source]]'' (2006)
* ''[[Half-Life 2: Episode One]]'' (2006)
* ''[[Half-Life 2: Episode Two]]'' (2007)
* ''[[Team Fortress 2]]'' (2007)
* ''[[Portal (video game)|Portal]]'' (2007)
* ''[[Left 4 Dead]]'' (2008)
* ''[[Left 4 Dead 2]]'' (2009)
* ''[[Alien Swarm]]'' (2010)
* ''[[Portal 2]]'' (2011)
* ''[[Counter-Strike: Global Offensive]]'' (2012)


====Games by other developers====
* ''[[Vampire: The Masquerade – Bloodlines]]''<ref>{{cite web| url=http://www.gamespot.com/articles/vampire-the-masquerade-bloodlines-designer-diary-3/1100-6085643/| title=Vampire: The Masquerade - Bloodlines Designer Diary #3| date=December 16, 2003| website=[[GameSpot]]| accessdate=January 4, 2015| deadurl=no| archiveurl=https://web.archive.org/web/20160518130331/http://www.gamespot.com/articles/vampire-the-masquerade-bloodlines-designer-diary-3/1100-6085643/| archivedate=May 18, 2016| df=mdy-all}}</ref> (2004)
* ''[[Garry's Mod]]'' (2006)
* ''[[SiN Episodes]]'' (2006)
* ''[[Dark Messiah of Might and Magic]]'' (2006)
* ''[[The Ship (video game)|The Ship]]'' (2006)
* ''[[Kuma\War]]'' (2006)
* ''[[Dystopia (video game)|Dystopia]]'' (2007)
* ''[[Insurgency: Modern Infantry Combat]]'' (2007)
* ''[[Zombie Panic! Source]]'' (2007)
* ''[[Silent Hill Alchemilla]]'' (2015)
* ''[[Zeno Clash]]''<ref>{{cite web| url=http://www.rockpapershotgun.com/2012/06/07/hieronymus-ace-team-explain-zeno-clash-ii/| title=Hieronymus: ACE Team Explain Zeno Clash II| date=June 7, 2012| publisher=[[Rock, Paper, Shotgun]]| accessdate=January 4, 2015| deadurl=no| archiveurl=https://web.archive.org/web/20150405201442/http://www.rockpapershotgun.com/2012/06/07/hieronymus-ace-team-explain-zeno-clash-ii/| archivedate=April 5, 2015| df=mdy-all}}</ref> (2009)
* ''[[NeoTokyo (video game)|NeoTokyo]]'' (2009)
* ''[[Bloody Good Time]]'' (2010)
* ''[[Vindictus]]'' (2010)
* ''[[Pirates, Vikings and Knights II]]'' (2010)
* ''[[E.Y.E.: Divine Cybermancy]]'' (2011)
* ''[[No More Room in Hell]]'' (2011)
* ''[[Nuclear Dawn]]'' (2011)
* ''[[Postal III]]'' (2011)
* ''[[Dino D-Day]]'' (2011)
* ''[[Dear Esther]]'' (2012)
* ''[[Black Mesa (video game)|Black Mesa]]'' (2012)
* ''[[Tactical Intervention]]'' (2013)
* ''[[The Stanley Parable]]'' (2013)
* ''[[Blade Symphony]]'' (2014)
* ''[[Consortium (video game)|Consortium]]'' (2014)
* ''[[Contagion (video game)|Contagion]]'' (2014)
* ''[[Insurgency (video game)|Insurgency]]'' (2014)
* ''[[Titanfall]]'' (2014)
* ''[[Fistful of Frags]]'' (2014)
* ''[[Portal Stories: Mel]]'' (2015)
* ''[[The Beginner's Guide]]'' (2015)
* ''[[Infra (video game)|Infra]]'' (2016)
* ''[[Titanfall 2]]'' (2016) (modified)<ref>{{cite web |title=E3 2016: Respawn Talks Content Variety, Reworked Engine in Titanfall 2 |url=https://www.hardcoregamer.com/2016/06/14/e3-2016-respawn-talks-content-variety-reworked-engine-in-titanfall-2/212196/}}</ref>
* ''[[Day of Infamy (video game)|Day of Infamy]]'' (2017)
* ''[[Apex Legends]]'' (2019) (modified)<ref>{{cite web |title=Apex Legends: the Titanfall 2 engine evolved? |url=https://www.eurogamer.net/articles/digitalfoundry-2019-apex-legends-tech-analysis}}</ref>

===Source 2===
* ''[[Dota 2]]'' (2013) (ported from Source in 2015)
* ''[[The Lab (video game)|The Lab]]'' (2016) (''Robot Repair'' only; rest of the minigames were created with the [[Unity engine]])
* ''[[Artifact (video game)|Artifact]]'' (2018)
* ''[[Dota Underlords]]'' (2019)

==See also==
{{Portal|Video games}}
* [[First-person shooter engine]]
* [[List of Source engine mods]]

==References==
{{Reflist}}

{{Commons category}}

{{Valve Corporation}}
{{Video game engines}}

{{DEFAULTSORT:Source (Game Engine)}}
[[Category:2004 software]]
[[Category:Game engines for Linux]]
[[Category:Proprietary software]]
[[Category:Source (game engine)]]
[[Category:Video game engines]]