Source (game engine)
Source is a 3D game engine developed by Valve. It debuted as the successor to GoldSrc in 2004 with the releases of Half-Life: Source, Counter-Strike: Source, and Half-Life 2. It is most well-known for its usage by Valve, but the engine has been used both by small teams and individuals to create modifications of Valve games,[1] and other studios creating distinct games, notably Troika Games title Vampire: The Masquerade – Bloodlines. Valve continued to create incremental updates to the Source engine after its 2004 release, most of which coincided with games created by Valve. In the late 2010s, Valve created the Source 2 to replace Source, with it publically debuting alongside Half-Life: Alyx. The Source engine is most well known for its advancements in physics, AI, and graphics.[2]
| Developer(s) | Valve |
|---|---|
| Initial release | October 2004 |
| Written in | C++ |
| Middleware | Havok |
| Predecessor | GoldSrc |
| Successor | Source 2 |
| License | Proprietary |
History edit
Source distantly originates from the GoldSrc engine, itself a heavily modified version of John Carmack's Quake engine with some code from the Quake II engine. Carmack commented on his blog in 2004 that "there are still bits of early Quake code in Half-Life 2".[3] Valve employee Erik Johnson explained the engine's nomenclature on the Valve Developer Community:[4]
When we were getting very close to releasing 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 forked off the code in VSS to be both
/$Goldsrcand/$Src. 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 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 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[5] 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.[6]
Modularity and notable updates edit
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, 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 mods without the developers performing upgrades to code and, in some cases, content.[7] Both cases required markedly less work to update its version than competing engines.
Source 2006 edit
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. HDR rendering and color correction were first implemented in 2005 using Day of Defeat: Source, which required the engine's shaders to be rewritten.[8] The former, along with developer commentary tracks, were showcased in Half-Life 2: Lost Coast. Episode One introduced Phong shading and other smaller features. Image-based rendering technology had been in development for Half-Life 2,[9] 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 polygonal objects.[10]
Source 2007 edit
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.[citation needed] An in-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.[11] 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.[12] However, support on the PC was experimental and unstable[13] until the release of Left 4 Dead.[14] Multiprocessor support was later backported to Team Fortress 2 and Day of Defeat: Source.[15] 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.[16] Program code can be ported from PC to Xbox 360 simply by recompiling it.[17] 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.[18]
Left 4 Dead branch edit
The Left 4 Dead branch is an overhaul of many aspects of the Source engine through the development of the Left 4 Dead series. Multiprocessor support was further expanded, allowing for features like split screen multiplayer, additional post-processing effects, event scripting with Squirrel, and the highly-dynamic 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 Steamworks integration creating what they called "the best console version of the game".[19]
OS X, Linux, and Android support edit
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 would be released simultaneously for Windows and Mac.[20][21] 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.[22] 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.[23] In May 2014, Nvidia released ports of Portal and Half-Life 2 to their Tegra 4-based Android handheld game console Nvidia Shield.[24]
Tools and resources edit
Source SDK edit
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.[citation needed]
There are three applications packaged in the Source SDK: Hammer Editor, Model Viewer, and Face Poser. 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 facial expressions, gestures and movements for characters, lip sync speech, and sequence expressions and other acting cues and preview what the scene will look like in the game engine.[25]
Hammer Editor edit
The 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. Level geometry is created with 3D polygons called brushes; each face can be assigned a texture which also defines the properties of the surface such as the sounds used for footsteps.[26] Faces can also be converted into a displacement allowing for more natural shapes such as hills to be created.
Scenery objects or complex geometry can be imported as separate 3D models from the game directory. These models can also be used as physics objects or interactive props. The editor also features an in-depth logic I/O system that can be used to create complex interactive elements. Signals to trigger different responses or change the state of an entity can be sent between entities such as buttons, NPCs, intangible trigger brushes, and map props.
Source Dedicated Server edit
The Source Dedicated Server (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:Source and SourceMod, which together provide a framework on top of SRCDS for custom modification of gameplay on existing titles.[27][28]
Source Filmmaker edit
Source Filmmaker (SFM) is a 3D animation application that was built from within the Source engine.[29] Developed by Valve, the tool was originally used to create movies for Day of Defeat: Source and Team Fortress 2. It was also used to create some trailers for Source Engine games. SFM was released to the public in 2012.
Destinations Workshop Tools edit
In June 2016, Valve released the Destinations Workshop Tools, a set of free virtual reality (VR) creation tools running using the Source 2 SDK.[30]
Valve Developer Community edit
In June 2005, Valve opened the Valve Developer Community wiki. It replaced Valve's static Source SDK documentation with a full MediaWiki-powered community site.[31]
Academic papers edit
Valve staff have occasionally produced professional and/or academic papers for various events and publications, including SIGGRAPH, Game Developer Magazine and Game Developers Conference, explaining various aspects of Source engine's development.[32]
Notable games using Source edit
Titanfall, Titanfall 2, and Apex Legends are not included because their engines, while originally based on the Source SDK, were modified to the point that they are effectively different engines.[36]
Source 2 edit
A successor to Source, Source 2, was announced by Valve at the Game Developers Conference in March 2015.[37] There, Valve stated that it would be free to use for developers, with support for the Vulkan graphical API, as well as using a new in-house physics engine called Rubikon.[38][39] In June 2015, Valve announced that Dota 2, originally made in the Source engine, would be ported over to Source 2 in an update called Dota 2 Reborn.[40][41] Reborn was first released to the public as an opt-in beta update that same month before officially replacing the original client in September 2015, making it the first game to use the engine.[42][43] The engine had succeeded Source by the late 2010s.
See also edit
Notes edit
- ^ Ported to Source 2 in 2015
References edit
- ^ Birsner, Chris (August 22, 2021). "10 Best Half-Life 2 Mods". TheGamer. Retrieved November 30, 2023.
- ^ Mitra, Ritwik (January 26, 2020). "11 Best Video Game Engines, Ranked". Game Rant. Retrieved November 30, 2023.
- ^ . John Carmack's Blog. December 31, 2004. Archived from the original on May 17, 2006.
- ^ Johnson, Erik (September 1, 2005). "Talk:Erik Johnson". Valve Developer Community. Archived from the original on February 15, 2012. Retrieved August 15, 2007.
- ^ Hodgson, David (2004). Half-Life 2: Raising the Bar. Prima Games. ISBN 0-7615-4364-3.
- ^ O'Donnell, Ryan (July 19, 2004). "Counter-Strike: Source - Full-Screen E3 2004 Presentation". GameSpy. from the original on March 4, 2016. Retrieved April 20, 2015.
- ^ "New Update Breaking New and Old Mods?". PlanetPhillip. from the original on October 21, 2014. Retrieved October 17, 2014.
- ^ Valve. Half-Life 2: Lost Coast (PC).
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.
- ^ . DriverHeaven.net. Archived from the original on June 28, 2009. Retrieved November 21, 2009.
- ^ . 1UP.com. Archived from the original on July 13, 2006. Retrieved July 14, 2006.
- ^ "Face-to-Face with TF2's Heavy". Steam news. May 14, 2007. from the original on May 8, 2009. Retrieved April 25, 2010.
- ^ "Interview: Gabe Newell". PC Zone. September 11, 2006. from the original on March 5, 2012. Retrieved September 20, 2006.
- ^ "Dual Core Performance". October 11, 2008. from the original on March 14, 2012. Retrieved December 23, 2008.
- ^ Lombardi, Doug (May 13, 2008). "PCGH interview about Left 4 Dead, part 2". Interviewer: Frank Stöwer. Retrieved December 23, 2008.[permanent dead link]
- ^ Breckon, Nick (March 18, 2008). "Team Fortress 2 Update Adds Multicore Rendering". from the original on June 16, 2009. Retrieved August 19, 2009.
- ^ . Valve. Archived from the original on August 13, 2009. Retrieved August 8, 2009.
- ^ "Joystiq interviews Doug Lombardi about Xbox 360 Source". Joystiq. October 17, 2006. from the original on September 22, 2009. Retrieved August 8, 2009.
- ^ Yoon, Andrew (October 11, 2007). "Gabe Newell calls PS3 'waste of everybody's time'". Engadget. from the original on July 3, 2015. Retrieved April 20, 2015.
- ^ "Portal 2: Pretty Much Every PS3 Question Answered (And That Cake Thing, Too)". Sony Computer Entertainment America. April 14, 2011. Archived from the original on September 2, 2011.
- ^ "Valve to Deliver Steam & Source on the Mac". Valve. March 8, 2010. from the original on August 26, 2013. Retrieved March 8, 2010.
- ^ "Left 4 Dead 2, Team Fortress 2, Portal and Steam Coming to Mac in April". Kotaku. March 8, 2010. from the original on December 18, 2011. Retrieved March 8, 2010.
- ^ "Simple DirectMedia Layer - Homepage". from the original on April 21, 2018. Retrieved April 21, 2015.
- ^ "News - Source SDK 2013 Release". Steam. from the original on April 8, 2015. Retrieved April 21, 2015.
- ^ "The Greatest PC Games of All-Time – 'Half-Life 2′ and 'Portal' – Now Available on SHIELD". Nvidia. May 12, 2014. Archived from the original on May 13, 2014. Retrieved May 12, 2014.
- ^ "Source Engine Licensing - Information Sheet" (PDF). Valve Corporation. p. 6. Retrieved October 12, 2021.
- ^ "Building Crown, part two: layout design, textures, and the Hammer editor". PC Gamer. March 18, 2014. Retrieved September 24, 2021.
- ^ "MetaMod:S". from the original on July 1, 2014.
- ^ "SourceMod". from the original on June 1, 2014.
- ^ "Source Filmmaker". from the original on April 2, 2013. Retrieved March 31, 2013.
- ^ Crecente, Brian (June 8, 2016). "Valve rolls out free VR creation tool for new destinations workshop". Polygon. from the original on June 9, 2016. Retrieved June 9, 2016.
- ^ Maragos, Nich (June 29, 2005). "Valve Developer Community Wiki Opens". Game Developer. Retrieved July 30, 2022.
- ^ "Valve Publications". from the original on May 13, 2021. Retrieved June 6, 2021.
- ^ "Vampire: The Masquerade - Bloodlines Designer Diary #3". GameSpot. December 16, 2003. from the original on May 18, 2016. Retrieved January 4, 2015.
- ^ "Hieronymus: ACE Team Explain Zeno Clash II". Rock, Paper, Shotgun. June 7, 2012. from the original on April 5, 2015. Retrieved January 4, 2015.
- ^ "NEOTOKYO on Steam". Retrieved March 7, 2020.
- ^ Dunsmore, Kevin (June 14, 2016). "E3 2016: Respawn Talks Content Variety, Reworked Engine in Titanfall 2". Hardcore Gamer. Retrieved November 24, 2021.
- ^ Kollar, Philip (March 3, 2015). "Valve announces Source 2 engine, free for developers". Polygon. from the original on March 5, 2015. Retrieved March 3, 2015.
- ^ Mahardy, Mike (March 3, 2015). "GDC 2015: Valve Announces Source 2 Engine". IGN. from the original on March 4, 2015. Retrieved March 3, 2015.
- ^ Migdalskiy, Sergiy (March 2015). "Physics for Game Developers: Physics Optimization Strategies" (PDF). Game Developers Conference. (PDF) from the original on March 4, 2016. Retrieved October 2, 2015.
- ^ Martin, Michael (June 13, 2015). "Valve Announces Dota 2 Reborn". IGN. from the original on June 29, 2016. Retrieved July 10, 2016.
- ^ Macy, Seth (September 9, 2015). "Dota 2 Now Valve's First Ever Source 2 Game". IGN. from the original on September 10, 2015. Retrieved September 9, 2015.
- ^ Livingston, Christopher (June 12, 2015). "Valve announces Dota 2 Reborn, new engine coming". PC Gamer. from the original on June 15, 2015. Retrieved June 13, 2015.
- ^ Macy, Seth (September 9, 2015). "Dota 2 Now Valve's First Ever Source 2 Game". IGN. from the original on September 10, 2015. Retrieved September 9, 2015.