XenEngine

Xengine (also known as XenEngine) is a third-party Source Engine branch using licenced code, created by the Crowbar Collective for Black Mesa. It is a modified version of Source 2013 Multiplayer with additions from Team Fortress 2, whose development was influenced by the limitations of Source. Although initially only Cascade Shadow Mapping was planned, Crowbar Collective gained much more knowledge while working on the engine, which allowed for more experimentation and improvements, eventually leading to the introduction of  deferred lighting. Besides using Team Fortress 2's engine version as a base, this engine version is also a hybrid of the Portal 2 engine branch and Left 4 Dead engine branch.

Note:Although it uses Team Fortress 2 engine as a base, this engine does not provide VScript system, and additional features introduced in later versions of Source 2013 Multiplayer and Team Fortress 2 branch, since these features came out in the game much later than first Xengine versions were released.

Features

• Engine
  • Entity and Displacement Limit upgraded from 4k to 8k.
  • Backported a lot of optimizations from Left 4 Dead and Portal 2.
  • Backported some entities from Left 4 Dead and Portal 2.
  • Improved AI, whose behavior depends on the current difficulty level (some NPCs also support Main and Assault Behavior Trees from the ai folder).
  • Dynamic lights on a lightmap were swapped with new deferred lights, which have better performance.
  • Gbuffer that allows the addition of some modern, difficult-to-make effects.
  • Made from scratch Qt UI with the ability to be customized and add new stuff without limitations (VGUI can be reenabled with -oldgameui launch parameter).
  • Uses  Fast ApproXimate Anti-Aliasing (FXAA) instead of  MultiSample Anti-Aliasing (MSAA) for anti-aliasing.
  • New and extended Post Processor.
  • Native Linux support.
  • Improved DirectX 9.0c shaders
  • Enhanced multiplayer with fixes for the client and server.
  • Dynamic music system.
  • Most of source's existing shaders have been rewritten in SM3, in order to be displayed properly with deferred rendering.

• Visuals
  • 4Way blends with support for 4 bumpmaps and tri-planar mapping, enabling all the options from other material shaders.
  • Cascaded Shadow Mapping with viewmodel self-shadowing.
  • Parallax Occlusion Mapping.
  • Procedural Moss.
  • Deferred lighting - A technique that allows lights to be rendered with little performance loss.
  • Dynamic lighting system with PBR-based lighting and speculars.
  • PCCS-based soft shadows.
  • Light cookies for both new point light and new spot light, the last can be animated.
  • Support for up to 2K dynamic lights per scene and all rendering features on secondary render targets (reflection/refraction, monitors, TV screens, etc.)
  • Upgraded flashlight using the new deferred lighting system.
  • Godrays with disk for both the sun and local lights (which also support the "Fancy" godrays type).
  • Screenspace Fog ("Xog"), that can be applied globally or locally using cuboid/ellipsoid volumes.
  • Flowing water.
  • Swaying trees.
  • Cinematic lens flares.
  • Web shader.
  • Upgraded tonemapping with bloom which uses a modified version of the Reinhard filter.
  • Optimized shaders for faster compilation and better runtime performance.
• Tools
  • In-game new lights editor and xog editor.
  • Multiple VRAD upgrades, such as support for Alpha-Tested textures, 4-way blends, baked Ambient Occlusion, Real Sky Ambient Light, and more.
  • 64-bit shader compiler.

Removed

• DirectX compatibility levels support lower than 9.0 (dxlevel 90)

Support for DirectX 8.1 and 8 GPUs has been dropped, and never supported anyway due to deferred lighting only support DirectX 9 and many players already have DirectX 9 capable graphics card.

• Projected textures

The entity was removed because it renders scene twice, making it very expensive.

• MSAA anti-aliasing

While MSAA technically produce sharper results than any post-processing based methods like FXAA and TAA, due to MSAA being complex to implement on deferred renderer (also includes deferred lighting), which also makes it more expensive than forward renderer, and because of Xengine implementation of deferred lighting causing MSAA to have haloing/outline effect, this anti-aliasing method was replaced with FXAA.

• Reflections from func_reflective_glass

The entity is still available, but the shader is not ported, it shows wireframe instead of reflection.

• WorldVertexTransition

The shader is not ported. All the features is available in LightmappedGeneric.

System Requirements

Windows
	Minimum	Recommended
Operating system (OS)	10
Processor (CPU)	2.6GHz Dual Core Processor or Greater	3.2GHz Quad Core Processor or Greater
System memory (RAM)	6 GB RAM	8 GB
Hard disk drive (HDD/SSD)	30 GB
Video card (GPU)	DirectX 9.0 Shader Model 3 capable 2 GB VRAM	DirectX 9.0 Shader Model 3 capable 4 GB VRAM or greater

Linux
	Minimum	Recommended
Operating system (OS)	Ubuntu 14.0+ or other Linux distros
Processor (CPU)	2.6GHz Dual Core Processor or Greater	3.2GHz Quad Core Processor or Greater
System memory (RAM)	4 GB RAM	6 GB
Hard disk drive (HDD/SSD)	30 GB
Video card (GPU)	Vulkan 1.3 capable 2 GB VRAM	Vulkan 1.3 capable 3 GB VRAM or greater
Other	NVIDIA - Does not support the  Nouveau display driver	NVIDIA - Does not support the  Nouveau display driver

Media

Availability and usage

Tip:The authoring tools for this branch have been released and are available directly from Black Mesa\bin\.

Note:There is no source code for this branch. However, you still can heavily modify the Qt UI via  QML programming language.

Note:All the shaders (including new lighting, etc) are stored in Black Mesa\hl2\hl2_misc_dir.vpk.

• 2020 Black Mesa
  • 2017 Black Mesa: Black Ops (restored version)
  • 2020 Black Mesa: Azure Sheep
  • 2025 Black Mesa: Blue Shift

See also

• Engine branches
• Black Mesa
• Alien Swarm Deferred
• Mapbase
• Strata Source

External links

• Chetan Jag's Blog about XenEngine
• Qt Qml 6.8.1- half of the documentation for Qt UI. You'll need it if you want to edit Qt UI for your Black Mesa mods.