View source for Source 2

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<span style="color:white; font-weight: bold;">{{For|about=the game engine
|the documentation on Source 2
|[[Source_2/Docs|Source 2 Documentation]]|}}</span>
{{Infobox engine
|title = Source 2
|image = Logo-Source_2.png<!-- using unofficial s2 logo for now, Wikipedia meanwhile uses Source 1 logo or does not have the logo. -->
|imagewidth = 280px
|imagetooltip = Unofficial logo of the Source 2 engine.
|image2 = Half-Life_Alyx_-_Screenshot_1.jpg
|imagetooltip2 = Screenshot of {{hla|1}}, using the {{source2|1}} Engine.
|developer = [[Valve|Valve Corporation]]
|releasedates = September 9, 2015<!-- based off Dota 2 Reborn update, first to use S2. -->
|codelang = [[WP:C++|C++]]
|sdk = [[Source_2/Docs|Source 2 Documentation]], game-specific Workshop Tools
|platform = {{Win|1}}, {{Mac|1}}, {{Linux|1}}, {{android|1}}, {{ios|1}}<!-- only first-party games -->
|website = 
|links = 
|license = [[WP:Proprietary software|Proprietary]]
|previousengine = {{Src|2}}
|nextengine = 
}}
{{todo|This page is not a stub but could use some more detail.}}
[[File:Screenshot-CS2-Source 2 engine.png|340px|thumb|In-game screenshot of {{CsgoMap|de_dust2}} in {{Cs2|1}}. It is also the most recent and latest {{src2|name}} game to be released.]]
[[File:Screenshot - CS2 LC Performance Test map.jpg|340px|thumb|Another in-game screenshot of {{Cs2|1}}, with the community-made map "[https://steamcommunity.com/sharedfiles/filedetails/?id=3181655247 Lost Coast] by CZXA1", showcasing the graphical capabilities of Source 2, such as [[Volumetric lighting]], 8K textures and lightmaps.]]
[[File:De_nuke - Source vs Source 2 comparison.jpg|340px|thumb|Comparison of {{CsgoMap|de_nuke}} map in {{src|1}} and {{source2|1}}.]]

{{source2|4}} is a 3D video game engine developed by [[Valve]] as a successor to {{src|4}}.
Introduced in 2015, it is used in {{dota2|1}}, {{svrh|1}}, {{hla|1}}, {{s&box|1}}, {{cs2|1}}, and much more.<!-- once this page is a bit longer, this list should probably be shortened. not while it's still kinda short, though. now it did! -->

Development of Source 2 was planned after the release of {{hl2ep2|1}} and other {{tob|1}} games. In 2010, {{l4d2|1}} was privately ported to the {{Src2|name}} engine as a tech demo, with one of the maps recreated in the Source 2 engine. The engine was later made public with the [[Dota 2 Workshop Tools]] Alpha in August 6th 2014 and formally announced by [[Valve]] in March of 2015 at the [[wikipedia: Game Developers Conference|Game Developers Conference]]. It was then implemented into ''Dota 2'' on June 17th 2015.
Valve has announced that Source 2 will be released to the public for free, and it will only take money should it be used for commercial products.

The engine is capable of rendering highly complex and well detailed scenes with minimal framerate drops, thanks to its new 64-bit support, new [[Source_2/Docs/Level_Design/Visibility|VIS]] method, alongside Vulkan, Direct3D 11, allowing for better multi-core rendering, better graphics and more efficient 3D rendering.

==Features==
=== Renderer ===
; Support MSAA, FXAA and TAA [[anti-aliasing]]
: Source 2 supports various anti-aliasing techniques, each with their own advantages & disadvantages. For more information, see [[anti-aliasing]] page.
; Native [[wikipedia: DirectX 11| DirectX 11®]] and [[wikipedia:Vulkan|Vulkan®]] support, with Shader Model 5.0 and later.
: Add various new rendering features that previous renderer used in Source (Direct3D 9) doesn't have.
; Support for both forward and [[deferred lighting|deferred]] rendering pipelines.
: Deferred rendering is a rendering technique that allow games to render as much lights with little performance impact. Deferred rendering are commonly used in most modern titles.
: Games such as {{cs2|1}} and {{hla|1}} uses forward renderer, while {{deadlock|1}} and {{dota2|1}} uses deferred renderer.
; [[Cascaded Shadow Maps]]
: Real-time dynamic shadows from skybox.
; [[Screen Space Ambient Occlusion]] support
: Simulate soft shadows on area such as walls and other objects by examining an onscreen pixel, and then comparing its location in a depth buffer to the pixels around it.
; [[Physically Based Rendering]] support
: PBR render graphics in a way that more accurately models the flow of light in the real world.
; [[Volumetric lighting]] support.
; Improved [[cubemap]] reflections
: Cubemaps in Source 2 are also [[Parallax Corrected Cubemaps|parallax corrected]].
; [[WEBM|WebM]]
: Source 2 uses WebM video, replacing the previous [[BIK|Bink Video format]]. This will allow in-game intro and cutscenes to take less storage space as WebM provides better compression compared to Bink. WebM is also a open-format compared to Bink video.
; Volumetric smokes {{only|{{cs2}}}}
: Smokes are now volumetric objects, that can be interacted by grenades, bullets, and more. It also react to lighting and the smokes fill the spaces naturally.

=== Physics ===
; [[Rubikon]]
: Valve's new in-house physics engine, replaced [[Havok]] previously used in Source to reduce licensing costs. Includes support for [[Cloth Simulation]].

=== Sound System ===
; [https://valvesoftware.github.io/steam-audio/ Steam Audio]
: Valve's new in-house sound system licensed under Apache 2.0 license, replaces proprietary Miles Audio System. 
; Improved Steam Audio
: Sounds have been reworked to better reflect the physical environment, be more distinct, and express more game state. They have also been rebalanced for a more comfortable listening experience.
; Other audio improvements
: Improved audio and voice processing.{{clarify}}
=== Networking ===
; Sub-tick system {{since|{{Cs2}}}}
: Tick rate no longer matters for moving, shooting, or throwing.
=== UI ===
; [[Panorama]]
: Valve's new Custom GUI interface that resembles modern web design and authoring (HTML5/CSS/JS). Using .XML and JavaScript files, developers can create dynamic and clean HUDs and menus and even high-quality in-game interactable panels.
: Scalable across any resolution, compared to [[VGUI]] used in previous Source games (prior to {{l4d|1}}) which would become small if the game is running at higher resolution.

=== Tools ===
; Integrated asset management via the [[Asset System]].
; New engine-integrated authoring tools, rebuilt from the ground up.
: All compiling tools except VRAD are now merged into one. The map compiling tool are named as [[Resourcecompiler]].
: All Source 2 engine tools can be launched from {{assetbrowser|2}}. It is similar to the now-deprecated Source SDK Launcher and [[Authoring Tools]] previously used in Source engine.
; {{Hammer5|2}}
: Completely rebuilt [[Valve Hammer Editor|Hammer]] level editor, featuring modern polygon mesh editing tools.
; Hardware accelerated ray-tracing for [[VRAD (Source 2)|VRAD]]
: Currently supports all NVIDIA RTX and AMD RX 6000 series (or later), and other RDNA2 GPU only. Intel Arc not supported yet.
: VRAD3 now requires graphics card with ray-tracing support to preview & bake lighting. This will allow VRAD to quickly calculates lighting data.
: VRAD3 is supported in all Source 2 games since 2022. Some games such as {{hla|1}} and {{Svrh|1}} still provides previous version (VRAD2) for users who want to compile maps lighting on systems that does not support hardware accelerated ray-tracing.

=== Programming ===
; 64-bit support
: Faster game performance, and allowing game to access over 4 GB of RAM. Previously, Source 2 also support 32-bit, which has been dropped with the release of {{dota2|4}} update in 2021 (except {{svrh|4}}).

=== Other ===
; Replaced brushes ([[BSP]]) with meshes ({{code|.vwnod_c}})
: BSP and Brushes (from Source, which goes back to {{quake|1}} and {{quake2|1}}), has been replaced with meshes, and BSP is replaced with [[WP:Octree|octree]] ({{code|.vwnod_c}}) for geometry partitioning. [[Brush entities]] has been also replaced with [[mesh entity]].
; Improved VIS
: Source 2's [[Source_2/Docs/Level_Design/Visibility|VIS]] works differently than {{quake|1}}, {{gldsrc|1}} and {{source|1}} [[Visleaf]] system.

==Limitations==
{{warning|Support for 32-bit, OpenGL, DirectX 9 (includes Direct3D 9), XAudio, and macOS versions below 10.14 were removed in 2021 with the {{dota2|1}} update. {{svrh|1}} is not affected. Newer games such as {{hla|1}} and {{cs2|1}} don't support them.<br>Newer games like {{Cs2|1}} will also require a CPU with SSE 4.2 support.}}
{{warning|Some games like {{cs2|2}} no longer support {{sq|1}}, making things non-trivial to port and with no chance of a proper transition period when both implementations are functional.}}

==Products using Source 2 {{Table tools|Source_2_games}}==
{{source 2 games}}

==Documentation==
* [[Source 2/Docs|Source 2 Documentation Index]]
* [[Source 2 General Discoveries]]

==See also==
* [[w:Source 2|Source 2 on Wikipedia]][[Category:Game engines]] [[Category:Valve]]
* {{Steamdb|icon=hide|tech/Engine/Source2|List of Source 2 games on Steam}} ({{steamdb}})
{{Source 2 topicon}} <!-- adds Source 2 category automatically -->