XenEngine

Xengine (also known as Xengine) is a third-party Source engine branch using licenced code. It is a modified version of the Source 2013 Multiplayer engine branch, whose development was influenced by the limitations of the Source Engine. Although initially only CSM was planned, they gained much more knowledge while working on the engine, which allowed for more experimentation and improvements, eventually leading to the introduction of a completely new lighting system,  Deferred lighting.

Features

Feature list from Chetan Jag's Blog and Black Mesa's page

• Engine
  • Entity Limit and Displacement upgraded 4k to 8k.
  • Temp lights were swapped with new deferred lights.
• Visuals
  • 4Way blends with support for 4 Bumpmaps.
  • Cascaded Shadow Mapping (CSM) with PCF-based soft shadows.
  • Parallax Occlusion Mapping (POM).
  • Dynamic Lighting System with PBR-based lighting, texture-projected lights with animated projection and godrays.
  • "Xog", or Volumetric Xen Fog, that can be applied globally or locally using cuboid/ellipsoid volumes.
  • Soft particles, flares, upgraded tonemapping and bloom.
  • Support for up to 2K dynamic lights per scene and all rendering features on secondary render targets (reflection/refraction, monitors, TV screens, etc.)
  • Optimized shaders for faster compilation and better runtime performance.
• Tools
  • In-game light and PostFX editors.
  • Multiple VRAD upgrades, such as support for Alpha-Tested textures, 4-way blends and more.

Availability

So far, only one title is running on the Xengine branch:

• Black Mesa

The SDK for this branch has been released and is available directly from Black Mesa's bin folder.

See also

• Chetan Jag's Blog, where Chetan Jaggi details his work on the XenEngine and provides some background information.
• Strata Source, an also third-party, modified branch of Source.