Source 2

is a 3D video game engine developed by Valve as a successor to .
Introduced in 2015, it is used in , , , , , and much more.
Development of Source 2 was planned after the release of and other games. In 2010, was privately ported to the 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 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 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 DirectX 11® and 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 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 and uses forward renderer, while and uses deferred renderer.
; 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.
; WebM
: Source 2 uses WebM video, replacing the previous 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 
: 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 ===
; 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.
=== Networking ===
; Sub-tick system 
: 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 ) 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 . It is similar to the now-deprecated Source SDK Launcher and Authoring Tools previously used in Source engine.
; 
: Completely rebuilt Hammer level editor, featuring modern polygon mesh editing tools.
; Hardware accelerated ray-tracing for 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 and 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 update in 2021 (except ).
=== Other ===
; Replaced brushes & BSP with octree Meshes
: BSP and Brushes (from Source, which goes back to and ), has been replaced with octree Meshes for geometry. Brush entities has been also replaced with mesh entity.
; Improved VIS
: Source 2's VIS works differently than , and Visleaf system.
==Limitations==
==Products using Source 2 ==
==Documentation==
* Source 2 Documentation Index
* Source 2 General Discoveries
==See also==
* Source 2 on WikipediaCategory:Game engines Category:Valve