View source for Volumetric lighting

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{{split|Somewhere down the line, this page ended up being used to document volumetric fog in addition to volumetric lighting…}}
'''Volumetric lighting''' is a lighting technique meant to simulate light bouncing off fog or dust particles in the air, such as a warehouse or foggy beach. It makes the player see beams of light shining from the sun or other light sources. Currently, the only {{valve|4}}-made software running on {{Source|4}} that supports Volumetric Lighting is {{sfm|4}}, however [[List_of_third-party_Source_games|some third-party engines]] incorporate volumetric lighting into {{ent|env_projectedtexture}}. If the game you are making maps for doesn't support volumetric lighting, you can use some workarounds seen [[WiseVol|here]].

Most {{Source2|4}} games have support for Volumetric lighting by default.

==Media==
<div style=width:100%;overflow:auto>
{| border="0" cellpadding="5"
|[[File:Sfm volumetrics.png|380px|thumb|center|Volumetric lighting in Source Filmmaker]]
|[[File:Deferred volumetrics.png|380px|thumb|center|Volumetric lighting in Alien Swarm Deferred]]
|[[File:Des_volumetrics.png|380px|thumb|center|Volumetric lighting in Portal 2: Desolation]]
|[[File:Hlvr-sfm-volumetrics.png|380px|thumb|center|Volumetric lighting in Half Life Alyx]]
|}
</div>
<div align="center" style=width:100%;overflow:auto>
{| border="0" cellpadding="4"
|[[File:volumetric_projected_texture_p2ce.jpg|400px|thumb|center|Volumetric lighting in Portal 2: Community Edition]]
|}
</div>

==Native Support==
==={{src|4}}===

{| class="wikitable" width="500px"
|-
! Game !! Supports
|-
| {{src04|4}}<br>{{src06|4}}<br>{{src07|4}}<br>{{src09|4}}/{{srcmp|4}}<br>{{src13|4}}<br>{{hls|4}}<br>{{dods|4}}<br>{{hl2|4}}<br>{{hl2ep1|4}}<br>{{hl2ep2|4}}<br>{{as|4}}<br>{{asrd|4}}<br>{{hldms|4}}<br>{{hl2dm|4}}<br>{{hl2lc|4}}<br>{{css|4}}<br>{{tf2|4}}<br>{{portal|4}}<br>{{l4d|4}}<br>{{l4d2|4}}<br>{{portal2|4}}<br>{{bms|4}} || {{No}}
|-
| {{asd|4}}<br>{{apex|4}}<br>{{p2d|4}} || {{Yes}}
|-
| {{sfm|4}}<br>{{strata|4}} || {{Yes|Yes ({{ent|env_projectedtexture}})}}
|}

==={{src2|4}}===

{| class="wikitable" width="500px"
|-
! Game !! Supports
|-
| {{hlalyx|4}} || {{Yes}}
|-
| {{cs2|4}} || {{Yes}}
|-
| {{sbox|4}} || {{Yes}}
|}

==Using models/textures to fake volumetric lighting==
<div style=width:100%;overflow:auto>
{| border="0" cellpadding="4"
!  !! Using vollight_stainedglass.mdl !! 
|[[File:Fakemdl vol mviever.png|500px|thumb|center|Model in Hammer]]
|[[File:Mdlvoludem.png|500px|thumb|center|Model in engine]]
|}
</div>

<div style=padding-left:28px;width:99%;overflow:auto;>
{| border="0" cellpadding="4"
!  !! Using vol_light128x128.mdl !! 
|[[File:128x vollight inhammer.png|500px|thumb|center|Model in Hammer]]
|[[File:128x vollight in.png|500px|thumb|center|Model in engine]]
|}
</div>

{{Note|On [[DirectX Versions|DirectX]] 9, volumetric lighting on Old Engine was slightly less visible compared to using DX8 level. However, the volumetric lighting on New Engine DX9 was even less visible (or nearly invisible) compared to Old Engine's DX9. This is likely due to a bug (or changes to the lighting) on Source 2007 and later.{{Cite|1}}{{Cite|2}}}}

{| class=standard-table
!  !! Old Engine !! New Engine ({{src13|name}})
|-
| DirectX 8.1 (and earlier) || [[File:Trainstation volumetric DX81 Source 2006.jpg|Volumetric lighting on Old Engine - DirectX 8.1 ({{code|dxlevel 81}})|512px]] || [[File:Trainstation volumetric DX81 Source 2013.jpg|Volumetric lighting on New Engine - DirectX 8.1 ({{code|dxlevel 81}})|512px]]
|-
| DirectX 9.0+ || [[File:Trainstation volumetric DX95 Source 2006.jpg|Volumetric lighting on Old Engine - DirectX 9.0+ ({{code|dxlevel 95}})|512px]] || [[File:Trainstation volumetric DX95 Source 2013.jpg|Volumetric lighting on New Engine - DirectX 9.0+ ({{code|dxlevel 95}})|512px]]
|}


{{references|1=
{{ref2|cite id=1|Jasper Carmack ({{Twitter|@JasperCarmack|icon=hide}}) (April 3, 2024). "{{Twitter|JasperCarmack/status/1775312261743079483|Comparing the differences between Half-Life 2 (Legacy / "DX8" shaders) on the left and (Modern) DX9+ shaders on the right.|icon=hide}}". ''{{twitter}}''. Retrieved {{#time: F d, Y }}.}}
{{ref2|cite id=2|Jasper Carmack ({{Twitter|@JasperCarmack|icon=hide}}) (April 3, 2024). "{{Twitter|JasperCarmack/status/1775370362198601835|When loading the save for comparison, you need to wait a little bit because the light glows are scripted to come on after a delay. So 1 {{=}} dx8, 2 {{=}} dx9 on load, 3 {{=}} dx9 after 5 seconds|icon=hide}}". ''{{twitter}}''. Retrieved {{#time: F d, Y }}.}}
}}

== See also ==
*[[Env volumetric fog volume]]
*[[Env volumetric fog controller]]
*[[Half-Life:_Alyx_Workshop_Tools/Source_Filmmaker/Working_With_Volumetrics| Working With Volumetrics]]
*[[WiseVol]]

== External links ==
*[https://www.youtube.com/watch?v=ybSYhHx84xI YOUTUBE How To Create Sunbeams using Volumetric Fog in Source 2 Hammer]
* [https://www.youtube.com/watch?v=hzn0cms5atU Volumetric lighting imitation trick with env_projectedtexture and translucent models (showcase)]
* [https://www.youtube.com/watch?v=sGArfKK-DXg Volumetric lighting imitation trick with env_projectedtexture and translucent models (tutorial)]
*{{w|Volumetric_lighting|Volumetric lighting}}
[[Category:Graphics]]
[[Category:Glossary]]
[[Category:Technical]]