View source for First-person shooter engine

{{VG Graphics}}
{{short description|Type of video game engine}}
A '''first-person shooter engine''' is a [[game engine|video game engine]] specialized for simulating [[3D graphics|3D]] environments for use in a [[first-person shooter]] [[video game]]. First-person refers to the view where the players see the world from the eyes of their characters. Shooter refers to games which revolve primarily around wielding firearms and killing other entities in the game world, either [[non-player character]]s or other players.

The development of the FPS graphic engines is characterized by a steady increase in technologies, with some breakthroughs. Attempts at defining distinct generations lead to arbitrary choices of what constitutes a highly modified version of an 'old engine' and what is a new engine.

The classification is complicated as game engines blend old and new technologies. Features considered advanced in a new game one year, become the expected standard the next year. Games with a combination of both older and newer features are the norm. For example, ''[[Jurassic Park: Trespasser]]'' (1998) introduced physics to the FPS genre, which did not become common until around 2002. ''[[Red Faction]]'' (2001) featured a [[destructible environment]], something still not common in engines years later.

==Timeline==
[[File:FPSChart.svg|600px|A diagram showing the history of FPS engines.]]

=== 1970s and 1980s: Early FPS graphics engines ===
{{see also|List of first-person shooter engines#Early FPS graphics engines}}

Game rendering for this early generation of FPS were already from the first-person perspective and with the need to shoot things, however they were mostly made up using [[vector graphics]].

There are two possible claimants for the first FPS, ''[[Maze War]]'' and ''[[Spasim]]''.<ref name="Rihal">{{cite web
| author=Dharamjit Rihal
| url=https://www.msu.edu/~rihaldha/projects/researchpaper.pdf
| title=The History of First-Person Shooters
| access-date=2009-07-04}}</ref> ''Maze War'' was developed in 1973 and involved a single player making his way through a maze of corridors rendered using a fixed perspective. [[Multiplayer video game|Multiplayer]] capabilities, where players attempted to shoot each other, were added later and were networked in 1974. ''Spasim'' was originally developed in 1974 and involved players moving through a wire-frame 3D universe. ''Spasim'' could be played by up to 32 players on the [[PLATO (computer system)|PLATO]] network.<ref>{{cite web
| url=http://www.gnomeslair.com/2006/12/history-of-fps-pictorial.html
| title=The history of the FPS. A pictorial
| date=2007-04-11
| access-date=2009-07-04}}</ref>

Developed in-house by [[Incentive Software]], the [[Freescape]] engine is considered to be one of the first proprietary 3D engines to be used for computer games, although the engine was not used commercially outside of Incentive's own titles. The first game to use this engine was the [[Puzzle video game|puzzle game]] ''[[Driller (video game)|Driller]]'' in 1987.<ref>{{cite web
| url=http://uk.retro.ign.com/articles/922/922505p1.html
| title=Exploring the Freescape
| publisher=IGN
| date=2008-10-22
| access-date=2009-07-04}}</ref>

===Early 1990s: Wireframes to 2.5D worlds and textures===
{{see also|List of first-person shooter engines#Early 1990s: Wireframes to 2.5D Worlds and Textures}}

Games of this generation often had "3D" in their names but were not capable of full 3D rendering. Instead, they used [[2.5D]] techniques, such as [[ray casting]], portal rendering or BSP rendering, to create a seemingly 3D environment from a 2D map, and flat [[Sprite (computer graphics)|sprites]] to draw enemies instead of [[3D modeling|3D models]]. These games also began to use [[Texture mapping|textures]] for environmental geometry instead of simple [[wire-frame model]]s or solid colors.

''[[Hovertank 3D]]'', from [[id Software]], was the first to use thoses techniques in 1990, but was still not using [[Texture mapping|textures]], a capability which was added shortly after on ''[[Catacomb 3D]]'' (1991), then with the [[Wolfenstein 3D engine]] which was later used for several other games. ''Catacomb 3D'' was also the first game to show the player character's hand on-screen, furthering the implication of the player into the character's role.<ref name="Rihal" />

''[[Wolfenstein 3D]]'' engine was the only one to use raycasting, unlike Catacomb how used a lien-rasterisation rendenring. But it was still very primitive. It did not apply textures to the floor and ceiling, and the [[ray casting]] restricted walls to a fixed height, and [[Level (video game)|levels]] were all on the same plane.

Even though it was still not using true 3D, [[Doom engine|id Tech 1]], first used in ''[[Doom (1993 video game)|Doom]]'' (1993) and again from [[id Software]], removed these limitations. It also first introduced the concept of [[binary space partitioning]] (BSP), in replacement of raycasting. Another breakthrough was the introduction of multiplayer abilities in the engine.<ref name="Rihal" /> However, because it was still using 2.5D, it was impossible to look up and down properly in ''Doom'', and all ''Doom'' levels were actually two-dimensional.<ref name="Rihal" /><ref name="Doom2Dunia">{{cite news
| url=http://www.maximumpc.com/article/features/3d_game_engines
| title=Doom to Dunia: A Visual History of 3D Game Engines
| author=Paul Lily
| newspaper=Pcgamer
| date=2009-07-21
| publisher=[[Maximum PC]]
| access-date=2009-07-05}}</ref> Due to the lack of a z-axis, the engine did not allow for [[room-over-room]] support.

''Doom'''s success spawned several games using the same engine or similar techniques, giving rise to the term ''Doom'' clones. The [[Build engine]], used in ''[[Duke Nukem 3D]]'' (1996), later removed some of the limitations of id Tech 1, such as the Build engine being able to have support for [[room-over-room]] by stacking sectors on top of sectors, but the techniques used remained the same.

===Mid 1990s: 3D models, beginnings of hardware acceleration===
{{See also|List of first-person shooter engines#Mid-1990s: Mid-1990s: 3D Models, beginnings of hardware acceleration}}

In the mid-1990s, game engines recreated true [[3-D computer graphics|3D]] worlds with arbitrary level geometry. Instead of sprites the engines used simply [[texture mapping|textured]] (single-pass texturing, no lighting details) [[polygon]]al objects.

[[FromSoftware]] released ''[[King's Field]]'', a full polygon free roaming first-person real-time action title for the [[Sony]] [[PlayStation]] in December 1994. [[Sega]]'s [[Sega 32X|32X]] release ''[[Metal Head]]'' was a first-person shooter [[mecha simulation game]] that used fully [[Texture mapping|texture-mapped]], [[3D computer graphics|3D polygonal graphics]].<ref>{{MobyGames|id=/metal-head|name=Metal Head}}</ref> A year prior, Exact released the [[Sharp X68000]] computer game ''Geograph Seal'', a fully 3D polygonal first-person shooter that employed [[platform game]] mechanics and had most of the action take place in [[Open world|free-roaming]] outdoor environments rather than the corridor labyrinths of ''Wolfenstein 3D''. The following year, Exact released its successor for the PlayStation console, ''[[Jumping Flash!]]'', which used the same game engine but adapted it to place more emphasis on the platforming rather than the shooting. The ''Jumping Flash!'' series continued to use the same engine.<ref>[http://www.the-nextlevel.com/review/retro/geograph-seal-x68000/ Geograph Seal (X68000)] {{Webarchive|url=https://web.archive.org/web/20160129224512/http://www.the-nextlevel.com/review/retro/geograph-seal-x68000/ |date=2016-01-29 }}, ''The Next Level''</ref><ref>{{cite web|url=http://www.ign.com/articles/2008/11/04/jumping-flashback|title=Jumping Flashback|first=Travis|last=Fahs|date=4 November 2008|website=ign.com|access-date=20 April 2018}}</ref>

''[[Dark Forces]]'', released in 1995 by [[LucasArts]], has been regarded as one of the first "true 3-D" first-person shooter games. Its engine, the [[Jedi (engine)|Jedi Engine]], was one of the first engines to support an environment in three dimensions: areas can exist next to each other in all three planes, including on top of each other (such as stories in a building). Though most of the objects in ''Dark Forces'' are sprites, the game does include support for textured 3D-rendered objects. Another game regarded as one of the first true 3D first-person shooter is [[Parallax Software]]'s 1994 shooter ''[[Descent (video game)|Descent]]''.{{Citation needed|date=May 2016}}

The [[Quake engine]] (''[[Quake (video game)|Quake]]'', 1996) used fewer animated sprites and used true 3D geometry and lighting, using elaborate techniques such as [[z-buffering]] to speed up the rendering. Levels in ''Quake'' and some subsequent engines are made with geometry objects called [[Brush (video games)|brushes]], which allow for map construction in three dimensions, rather than 2D maps projected in 3D, as ''Doom'' had done. ''Quake'' was also the first true-3D game to use a special map design system to preprocess and pre-render the 3D environment: the 3D environment in which the game took place (referred for the first time as a [[Level (video game)|Map]]) was simplified during the creation of the map to reduce the processing required when playing the game.

Static [[lightmap]]s and 3D light sources were also "baked" at render time and added to the [[Binary space partitioning|BSP]] files storing the levels. These features allowing for more realistic lighting than had previously been possible.

The first [[Graphics processing unit]]s<ref>like [[3dfx Interactive|Voodoo]], [[Voodoo 2]], or [[Riva TNT]], or later the more powerful [[DirectX]] 6.0 chipsets such as [[Voodoo3]], [[RIVA TNT2]] and [[Rage 128]]</ref> appeared in the late 1990s, but many games still supported software rendering at that time. [[id Tech 2]] (''[[Quake II]]'', 1997) was one of the first games to take advantage of hardware accelerated graphics<ref>{{cite web |url=http://www.idsoftware.com/business/idtech2/ 
 |title=id Tech 2 
 |publisher=[[id Software]] 
 |access-date=2009-07-05 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20091108191715/http://www.idsoftware.com/business/idtech2/ 
 |archive-date=November 8, 2009}}</ref> ([[id Software]] later reworked ''Quake'' to add [[OpenGL]] support to the game).

[[GoldSrc]], the engine derived from the [[Quake engine]] by [[Valve Corporation|Valve]] for ''[[Half-Life (video game)|Half-Life]]'' (1998), added [[Direct3D]] support, and a [[Skeletal animation|skeletal]] framework to better render the [[Non-player character|NPCs]],<ref name="hl2GameSpot">{{cite web
 |url         = http://uk.gamespot.com/features/halflife_final/part32.html
 |title       = half Life: Improved Technology
 |publisher   = [[GameSpot]]
 |access-date  = 2009-07-08
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20110225015808/http://uk.gamespot.com/features/halflife_final/part32.html
 |archive-date = 2011-02-25}}</ref><ref name="Doom2Dunia3">{{cite news
| url=http://www.maximumpc.com/article/features/3d_game_engines?page=0%2C3
| title=Doom to Dunia: A Visual History of 3D Game Engines
| author=Paul Lily
| newspaper=Pcgamer
| date=2009-07-21
| publisher=[[Maximum PC]]
| access-date=2009-07-05}}</ref> and also greatly improved the [[Game artificial intelligence|NPCs artificial intelligence]] (AI) compared to the Quake engine.<ref name="hl2GameSpot"/>

===Late 1990s: Full 32-bit color, and GPUs become standard===
{{See also|List of first-person shooter engines#Late-1990s: 32-bit color, GPUs becomes standard}}

This period saw the introduction of the first video cards with [[Transform, clipping, and lighting|Transform, clipping, and lighting (T&L)]]. The first card with this innovative technology was the [[GeForce 256]]. This card was superior to what 3dfx had to offer at the time, namely [[Voodoo3]], which only fell short because the lack of T&L. Companies such as [[Matrox]] with their [[Matrox G400|G400]], and [[S3 Graphics|S3]] with their [[S3 Savage|Savage4]] were forced to withdraw from the 3D gaming market during this time period. One year later, [[ATI Technologies|ATI]] released their [[Radeon R100|Radeon 7200]], a true competing graphics card line.

While all games of this period supported [[16-bit color]], many were adopting [[Color depth#12-bit color|32-bit color]] (really 24-bit color with an 8-bit alpha channel) as well. Soon, many benchmark sites began touting 32-bit as a standard. The [[Unreal Engine]], used in a large number of FPS games since its release, was an important milestone at the time.<ref>{{cite web
| url=http://www.beyondunreal.com/articles/history-of-unreal-part-1/
| title=History of Unreal - Part 1
| date=2005-05-31
| publisher=beyondunreal.com
| access-date=2009-08-05}}</ref> It used the [[Glide API]], specifically developed for [[3dfx Interactive|3dfx]] GPUs,<ref name="Doom2Dunia3"/> instead of [[OpenGL]]. Probably the biggest reason for its popularity was that the engine architecture and the inclusion of a [[UnrealScript|scripting language]] made it easy to [[Modding|mod]] it.<ref>{{cite web
| url=http://www.beyondunreal.com/articles/history-of-unreal-part-1/?page=2
| title=History of Unreal - Part 1
| date=2005-05-31
| quote=''Probably the biggest draw to Unreal was the ability to mod it. Tim Sweeney (Founder of Epic) wrote a simple scripting engine into the game called UnrealScript.''
| publisher=beyondunreal.com
| access-date=2009-07-05
| archive-date=2011-07-07
| archive-url=https://web.archive.org/web/20110707231206/http://www.beyondunreal.com/articles/history-of-unreal-part-1/?page=2
| url-status=dead
}}</ref><ref name="informitUnreal">{{cite web
| url=http://www.informit.com/articles/article.aspx?p=1377834
| title=Introduction to Unreal Technology
| date=2009-07-21
| publisher=[[InformIT (publisher)|InformIT]]
| access-date=2009-08-08}}</ref> One other improvement of Unreal compared to the previous generation of engines was its [[Computer network|networking technology]], which greatly improved the scalability of the engine on [[Multiplayer video game|multiplayer]].<ref>{{cite web
| url=http://unreal.epicgames.com/Network.htm
| title=Network
| date=1999-07-21
| publisher=[[Epic Games]]
| access-date=2009-08-08
| archive-date=2010-07-28
| archive-url=https://web.archive.org/web/20100728233924/http://unreal.epicgames.com/Network.htm
| url-status=dead
}}</ref>

[[id Tech 3]], first used for ''[[Quake III Arena]]'', improved from its predecessor by allowing to store much more complex and smoother animations. It also had improved lighting and [[Shadow volume|shadowing]] and introduced [[shader]]s and curved surfaces.<ref name="Doom2Dunia4">{{cite news
| url=http://www.maximumpc.com/article/features/3d_game_engines?page=0%2C4
| title=Doom to Dunia: A Visual History of 3D Game Engines
| author=Paul Lily
| newspaper=Pcgamer
| date=2009-07-21
| publisher=[[Maximum PC]]
| access-date=2009-07-05}}</ref>

===Early 2000s: Increasing detail, outdoor environments, and rag-doll physics===
{{See also|List of first-person shooter engines#Early 2000s: increasing detail, outdoor environments, rag-doll physics}}

New graphics hardware provided new capabilities, allowing new engines to add various new effects, such as particle effects or fog, as well as increase texture and polygon detail. Many games featured large outdoor environments, vehicles, and [[rag-doll physics]].

Average Video Hardware requirements: a GPU with hardware [[T&L]] such as the DirectX 7.0 [[GeForce 2]] or [[Radeon R100|Radeon 7200]] was typically required. The next-generation [[GeForce 3]] or [[Radeon 8500]] were recommended due to their more efficient architecture, though their DirectX 8.0 vertex and pixel shaders were of little use. A handful of games still supported DirectX 6.0 chipsets such as [[RIVA TNT2]] and [[Rage 128]], and software rendering (with an integrated [[Intel GMA]]), though this was apparent that even a powerful CPU could not compensate for the lack of hardware T&L.

Games engines originally developed for the [[Personal computer|PC]] platform, like the [[Unreal Engine 2]], started to be adapted for [[History of video game consoles (sixth generation)|sixth generation consoles]] like [[PlayStation 2]] or [[GameCube]], those now having the computer power to handle graphic-intensive video games.

===Mid 2000s: Lighting and pixel shaders, physics===
{{see also|List of first-person shooter engines#Mid 2000s: lighting and pixel shaders, physics}}

The new generation of graphics chips allowed [[Vertex and pixel shaders|pixel shader]]-based textures, [[bump mapping]], and lighting and shadowing technologies to become common. Shader technologies included [[HLSL]] (for [[DirectX]]), [[GLSL]] (for [[OpenGL]]), or [[Cg (programming language)|Cg]].

This resulted in the obsolescence of [[DirectX#Version history|DirectX 7.0]] graphics chips such as the widespread [[GeForce 2]] and [[Radeon R100|Radeon 7200]], as well as DirectX 6.0 chipsets such as [[RIVA TNT2]] and [[Rage 128]], and integrated [[Motherboard|on-board]] [[Intel GMA|graphics accelerators]]. Until this generation of games, a powerful CPU was able to somewhat compensate for an older video card. Average Video Hardware requirements: minimum was a [[GeForce 3]] or [[Radeon 8500]], strongly recommended was the GeForce FX, [[Radeon 9700]] (or other cards with [[High Level Shader Language#Pixel shader comparison|Pixel shader 2.x]] support). The Radeon 9700 demonstrated that [[Spatial anti-aliasing|anti-aliasing]] (AA) and/or [[anisotropic filtering]] (AF) could be fully usable options, even in the newest and most demanding titles at the time, and resulted in the widespread acceptance of AA and AF as standard features. AA and AF had been supported by many earlier graphics chips prior to this but carried a heavy performance hit and so most gamers opted not to enable these features.

<!-- Commented out: [[File:Doom3shadows2.jpg|thumb|right|The shadowing effects of [[id Tech 4]] for ''[[Doom 3]]''.]] -->
With these new technologies game engines featured seamlessly integrated indoor/outdoor environments, used shaders for more realistic animations (characters, water, weather effects, etc.), and generally increased realism. The fact that the [[Graphics processing unit|GPU]] performed some of the tasks that were already done by the [[Central processing unit|CPU]], and more generally the increasing processing power available, allowed to add realistic physics effects to the games, for example with the inclusion of the [[Havok (software)|Havok]] physics engine in most video games.<ref>{{cite web
| url=http://www.hlhmod.com/physics.html
| title=Playing Dead: Physics in Pop Games
| year=2007
| publisher=hlhmod.com
| access-date=2009-08-09
| archive-url=https://web.archive.org/web/20090401042848/http://www.hlhmod.com/physics.html
| archive-date=2009-04-01
| url-status=dead}}</ref> Physics had been already added in a video game in 1998 with ''[[Jurassic Park: Trespasser]]'', but limited hardware capabilities at the time, and the absence of a [[middleware]] like Havok to handle physics had made it a technical and commercial failure.<ref>{{cite web
| url=http://www.gamasutra.com/view/feature/3339/postmortem_dreamworks_.php
| archive-url=https://web.archive.org/web/20080227075642/http://www.gamasutra.com/view/feature/3339/postmortem_dreamworks_.php
| url-status=dead
| archive-date=February 27, 2008
| title=Postmortem: DreamWorks Interactive's Trespasser
| date=1999-05-14
| publisher=[[Gamasutra]]
| access-date=2009-08-09}}</ref>

[[id Tech 4]], first used for ''[[Doom 3]]'' (2004), used an entirely dynamic [[per-pixel lighting]], whereas previously, 3D engines had relied primarily on pre-calculated per-vertex lighting or [[lightmap]]s and [[Gouraud shading]]. The [[Shadow volume]] approach used in ''Doom 3'' permitted more realistic lighting and shadows,<ref>{{cite web
| url=http://ixbtlabs.com/articles2/doom3/doom3.html
| title=Doom 3
| publisher=ixbtlabs.com
|quote=''The main advantage of the new system of lighting (besides the mentioned direct control of an artist over its masterpiece) is the capacity to render shadows in real time for every frame (...) Secondly, it's very hard to render muzzy, "soft" shadows prevailing in reality using shadow volumes. (...) Thirdly, summing up the two previous paragraphs we draw a conclusion that shadow volumes do not fit well for rendering shadows at vast open spaces.''
| access-date=2009-08-09}}</ref> but this came at a price as it could not render soft shadows, and the engine was primarily good indoors. This was later rectified to work with vast outdoor spaces, with the introduction of [[MegaTexture]] technology in the [[id Tech 4]] engine.

The same year, [[Valve Corporation|Valve]] released ''[[Half-Life 2]]'', powered by their new [[Source (game engine)|Source]] engine. This new engine was notable in that, among other things, it had very realistic facial animations for [[Non-player character|NPCs]], including what was described as an impressive [[Lip-syncing#First-person shooters|lip-syncing]] technology.<ref>{{cite web
| url=http://www.eurogamer.net/articles/r_half-life2_pc
| title=Half-Life 2
| date=2004-11-14
| publisher=[[Eurogamer]]
| quote=''But yet the incredibly lifelike detail and unparalleled attention to detail in the facial and body animation bring the characters to life like no game has ever even come close to doing. Six years ago there were a handful of facial models, bags of imagination and some great voice work; now we've got a huge cast list who all have plenty to say (with impressively accurate dynamic lip synching) and do so with such an impressive array of visible emotions that infuse the game with a head-turning credibility that will change the way people view games forever.''
| access-date=2009-08-09}}</ref>

===Late 2000s: The approach to Photorealism===
{{See also|List of first-person shooter engines#Late 2000s and beyond: the approach to photorealism}}

Further improvements in [[Graphics processing unit|GPUs]] like [[Shader|Shader Model 3]] and [[Unified shader model|Shader Model 4]], made possible by new graphic chipsets as [[GeForce 7 series|GeForce 7]] or [[Radeon R520|Radeon X1xxx]] series, allowed for improvements in graphic effects.

Developers of this era of 3D engines often tout their increasingly [[photorealistic]] quality. Around the same time, [https://esportsgenius.gg esports] were beginning to gain attention. These engines include realistic [[shader]]-based materials with predefined physics, environments with procedural and [[vertex shader]]-based objects ([[vegetation]], debris, human-made objects such as books or tools), [[procedural animation]], cinematographic effects ([[depth of field]], [[motion blur]], etc.), [[high-dynamic-range rendering]], and unified lighting models with soft shadowing and [[volumetric lighting]].

However, most of engines capable of these effects are evolutions of engines from the previous generation, such as [[Unreal Engine 3]], the [[Dunia Engine]] and [[CryEngine 2]], [[id Tech 5]] (which was used with ''[[Rage (video game)|Rage]]'' and makes use of the new [[MegaTexture|Virtual Texturing]] technology<ref>{{cite web|url=http://s09.idav.ucdavis.edu/talks/05-JP_id_Tech_5_Challenges.pdf|title=From Texture Virtualization to Massive Parallelization|date=August 2009|publisher=[[Id Software]]|archive-url=https://web.archive.org/web/20091007031619/http://s09.idav.ucdavis.edu/talks/05-JP_id_Tech_5_Challenges.pdf|archive-date=2009-10-07|url-status=dead|access-date=2009-07-07}}</ref>).

The first games using [[Unreal Engine 3]] were released in November 2006, and the first game to use [[CryEngine 2]] (''[[Crysis]]'') was released in 2007.

===Early 2010s: Graphic technique mixes===
Further improvements in [[Graphics processing unit|GPUs]] like [[Shader|Shader Model 5]], made possible by new graphic chipsets as [[GeForce 400 series]] or [[Radeon HD 5000 series]] and later, allowed for improvements in graphic effects. such as Dynamic [[Displacement Mapping]] and [[Tessellation (computer graphics)|Tessellation]].

As of 2010, two upcoming evolutions of major existing engines had been released: [[Unreal Engine 3]] in [[DirectX 11]] which powered Samaritan Demo<ref>{{cite web|url=https://www.youtube.com/watch?v=RSXyztq_0uM |archive-url=https://ghostarchive.org/varchive/youtube/20211222/RSXyztq_0uM |archive-date=2021-12-22 |url-status=live|title=Unreal Engine 3: Official Samaritan Demo|last=IGN|date=8 March 2011|access-date=20 April 2018|via=YouTube}}{{cbignore}}</ref> (which is used with ''[[Batman: Arkham City]]'', ''[[Batman: Arkham Knight]]'' and more DX11 based UE3 games) and [[CryEngine 3]], which powers ''[[Crysis 2]]'' and ''[[Crysis 3|3]]''.

Few companies had discussed future plans for their engines; [[id Tech 6]], the eventual successor to id Tech 5, was an exception. Preliminary information about this engine which was still in early phases of development tended to show that [[id Software]] was looking toward a direction where [[Ray tracing (graphics)|ray tracing]] and classic [[raster graphics]] would be mixed.<ref name="pcper">{{cite web|publisher=PC Perspective|title=John Carmack on id Tech 6, Ray Tracing, Consoles, Physics and more|url=http://www.pcper.com/article.php?aid=532|date=2008-03-12|quote=''What John does see ray tracing useful for is a very specific data model he has created called "sparse voxel octrees" that allow him to store immense amounts of data in a fashion that is easily accessed using ray tracing methods(...) This new data model and algorithm being worked on for id Tech 6 would allow, according to John, nearly infinite amounts of geometric detail in the world without the problems seen with tessellation engines or trying to store gigabytes of data locally.''|access-date=2010-03-27|archive-url=https://web.archive.org/web/20100314045408/http://www.pcper.com/article.php?aid=532|archive-date=2010-03-14|url-status=dead}}</ref> However, according to [[John D. Carmack|John Carmack]], the hardware capable of id Tech 6 did not yet exist.<ref name="carmack">{{cite news|publisher=[[Maximum PC]]|title=QuakeCon 08: id Tech 6 Will Utilin Carmack Interview. Rage, id Tech 6, Doom 4 Details, and More!|newspaper=Pcgamer |url=http://www.maximumpc.com/article/features/e3_2008_the_john_carmack_interview_rage_id_tech_6_doom_4_details_and_more?page=0%2C1|date=2008-07-15|quote=''I still think there’s one more generation to be had where we virtualize geometry with id Tech 6 and do some things that are truly revolutionary. (...) I know we can deliver a next-gen kick, if we can virtualize the geometry like we virtualized the textures; we can do things that no one's ever seen in games before.''}}</ref> The first title using the engine, ''[[Doom (2016 video game)|Doom]]'', was released in mid 2016.

In September 2015, [[Valve Corporation|Valve]] released [[Source 2]] in an update to ''[[Dota 2]]''.<ref>{{Cite web|url=http://www.dota2.com/reborn/updates/|title=Dota 2 - Reborn|website=Dota2.com|access-date=2016-06-23}}</ref>

==See also==
* [[Game engine]]
* [[List of game engines]]
* [[List of first-person shooter engines]]

== References ==
{{Reflist|2}}
{{Video game engines}}

{{DEFAULTSORT:First-Person Shooter Engine}}
[[Category:Video game engines| ]]