Volumetric lighting

Volumetric lighting, also known as "God rays", is used to add lighting effects(mainly FOG), to the world. It makes the player see beams of light shining from the sun or other light sources. Currently the only official Valve made Source branch that has support for volumetric lighting is Source Filmmaker, however some third-party engines incorporate volumetric lighting into env_projectedtexture If the game you are making maps for doesn't support volumetric lighting but you still want to add some to you map you can use some trick to get around it like This.

Also most versions of Source 2 has full support for volumetric lighting.

Media

Volumetric lighting in SFM

Todo: alien swarm deferred

Todo: hl alyx

Support

Source

Game	Supports
Source 2004 Source 2006 Source 2007 Source 2009/ Source Multiplayer Source 2013 Half-Life: Source Day of Defeat: Source Half-Life 2 Half-Life 2: Episode One Half-Life 2: Episode Two Alien Swarm Alien Swarm: Reactive Drop Half-Life Deathmatch: Source Half-Life 2: Deathmatch Half-Life 2: Lost Coast Counter-Strike: Source Team Fortress 2 Portal Left 4 Dead Left 4 Dead 2 Portal 2	NO
Black Mesa	YES
Alien Swarm Deferred	YES
Source Filmmaker	YES
Strata Source	YES
Apex Legends	N/A