Glowing textures (Source)

GoldSrc

Source Engine

Source 2

A glowing texture is one that does not require another form of light to be lit up. It can create its own lightmap independent of all lighting sources and may even create light itself. This does not mean that the surface will appear pure white, just that the face will ignore any light it would receive. This is a key feature as a "glowing" black stays black and does not get brighter. The face achieves what is called fullbright, where the texture's pixels appear exactly the same color as they were saved.

There are several different ways to create this effect available in the Source engine.

For glowing textures on models or brush faces:

• $selfillum parameter, specified in a material's VMT. - Use this for most purposes, not compatible with transparency.
• $detail parameter with $detailblendmode value of 5 or 6, specified in a material's VMT - Same as $selfillum, but more rudimentary and compatible with transparency.
• UnlitGeneric shader, specified in a material's VMT - Does not emit light, forces face to ignore all lighting, making it fullbright.

For glowing textures on brush faces only:

• Using the _minlight entity keyvalue.
• RAD file, mainly used for glowing textures on brushes ("texlights"). RAD files are the only form of glowing textures that generate any map light. The file is processed line-by-line; each line is simply the name of the texture, the RGB value of the light, and then the brightness of the light. Common generic texlights can be found in White.
• %CompileNoLight material map compile flag - Disables generating lightmaps for a face even if using a lightmapped shader, making it fullbright. Not compatible with other compile flags without modifying VBSP.

For glowing textures on models only:

• $emissiveblend parameter, specified in a material's VMT. - Also compatible with Transparency, can be animated via flowtexture like water.
• Using info_lighting to "fool" a model into "thinking" it is brightly illuminated.

An image showing the differences between Selfillum, Emissiveblend and Detail glows.
(Click to Enlarge)

$selfillum

Self illumination applies "fake" light to a surface, regardless of the true light that the surface receives from the environment. This is useful for parts of a model that emit their own visible light, like the filament in a light bulb or a glowing LED on a control panel. The self illumination effect can be masked with a texture.

Warning:$selfillum cannot be used with $translucent or $alphatest on models. Use the UnlitGeneric shader instead or the $detail workaround.

Warning:Selfillum does not work with $phong. Selfillum only works with $normalmap, but $phong only works with $bumpmap, therefore making Phong and Selfillum mutually exclusive by proxy. This can be worked around by using $selfillummask and $basemapalphaphongmask

Confirm:Check for which platforms this is true. $selfillum doesn't require $normalmap at all and seems to work completely fine with $phong in at least .

Important:Requires sv_pure to be set to -1 in some games; see $detail method for a workaround.

LightmappedGeneric
{
    $basetexture props/tvscreen005a
    $selfillum 1
}

By default, $selfillum uses the alpha channel of the base texture as a mask. If the alpha channel of your base texture is used for something else, you can specify a separate $selfillummask texture.

LightmappedGeneric
{    
    $basetexture props/tvscreen005a
    $selfillum 1
    $selfillummask <texture>
}

With an opaque mask, $selfillum effectively works like UnlitGeneric. The surface will ignore all light from the environment and appear fullbright.

Mask values below 1.0 apply a minimum brightness effect to the surface, while still allowing it to receive light from the environment. This threshold effect is useful for objects like computer screens, which should be visible in darkness but become overwhelmed in bright sunlight.

Additional Parameters

$selfillumtint <RGB matrix>

Adjusts the color of the self-illumination effect. Default value is "[1 1 1]".

$selfillummaskscale <normal>

Scales the self-illumination effect strength. Default value is 1.0.

Note: Does not exist on , does exist on VertexLitGeneric in Alien Swarm

Todo:  In what other branches does this parameter exist?

$selfillummask <texture>

A dedicated mask texture for the effect. Might not work in Source 2006.

Note:Works like a color map.

Bug:Doesn't work on overlays in Counter-Strike: Global Offensive.  [todo tested in?]

Todo: How does this feature react to $phong in other branches than ?

Warning:Not on LightmappedGeneric, must use Alpha Channel of the $basetexture instead. ($selfillum 1 only)

Warning:Doesn't work on VertexLitGeneric when $bumpmap is present, except in Alien Swarm when $phong is present.

Warning: Source 2007 MUST use this!

$selfillum_envmapmask_alpha <boolean> (DX9+)

Has the material derive its self-illumination mask from the alpha channel of the $envmapmask.

Note:$selfillum_envmapmask_alpha replaces the original $selfillum command, so they cannot be used together.

Note:this mask is multiplied by 8. So to archive same results as other mask methods remember to divide $selfillumtint by 8

Warning:Only on VertexLitGeneric - Note that $envmapmask does not work with $bumpmap or $phong on VertexLitGeneric.

$selfillumtexture <texture>

Use a selfillum texture.

Note:Deprecated since Source 2007.

Note:use $emissiveblend instead

$selfIllumfresnel <boolean> (DX9+) (in all games since )

Shader(s): VertexLitGeneric

Allows the material to use Fresnel ranges.

Warning:Disables $normalmapalphaenvmapmask if enabled.

Warning:Doesn't work with $detail or $lightwarptexture, unless using $phong.

Warning:Requires $bumpmap.

$selfIllumFresnelMinMaxExp <matrix> (DX9+) (in all games since )

Default: 0.0 1.0 1.0. Not the same Fresnel ranges as $phongfresnelranges.

The first value is the minimum illumination, second value is the maximum illumination and the final value is the Fresnel exponent.

A selfillum mask texture.

$detail

If $selfillum is not a viable option, a $detail texture can be used instead. It can bypass the sv_consistency check on some games (on modern branches, sv_pure set to anything other than -1), such as in Counter-Strike: Source or Left 4 Dead 2, to allow glowing textures where textures with $selfillum would cause you to be kicked from the server.

VMT lines required for a $detail glow:

$detail   "models/weapons/pose/briefcase/briefcase_pickedup_red"
        
$detailscale 1        // scales the detail texture to same size as diffuse texture.
  
$detailblendmode 5    // 6 also works. 1 can be used if both are unavailable 
                      // (such as on LightmappedGeneric), although it will still 
                      // be affected by lighting.

$detailblendfactor can additionally be used to make the texture less bright.

The detail texture itself must be completely black with the parts that should be glowing colored. Dark colors will glow less. You cannot make a black glowing texture this way.

The Team Fortress 2 briefcase detail glow texture

$emissiveblend

$Emissiveblend is another alternative if $selfillum and $detail can not be used.
As an example, melee weapons in Left 4 Dead 2 that use $phong can not use $selfillum because $selfillum breaks when $bumpmap is used, which $phong requires. They also can't use $detail for glow, because the blood overlay already uses $detail. So the only option is $emissiveblend
Originally, $emissiveblend is supposed to be used for glowing and flowing textures, specifically the Vortigaunts blue shimmer in Half-Life 2: Episode Two where Alyx is being healed. However, it can also function as a basic selfillum alternative.

Static

This is an example of a static $emissiveblend texture. It will appear just like $selfillum does.

$EmissiveBlendEnabled 		1					// Enable EmissiveBlend. Like $selfillum 1	
$EmissiveBlendStrength 		1 					// how strong the entire glow effect is.
$EmissiveBlendTexture 		vgui/white			// This will be useless, but is required.
$EmissiveBlendBaseTexture 	Glow_texture_color	// this is the glowing texture.vtf
$EmissiveBlendFlowTexture 	vgui/white	 		// EmmisiveBlend can "flow" or move. But ours is static, so a white texture is used.
$EmissiveBlendTint 			" [ 1 1 1 ] "		// RGB glow intensity. Leave at 1 1 1. This can be used to change how strong each color should glow. So instead of using a darker red color, you may use [.5 1 1] to have red glow half as strong.
$EmissiveBlendScrollVector 	" [ 0 0 ] " 		// makes the EmmissiveBlend flow in either direction if a proper EmissiveBlendFlowTexture were set. But ours is static, so leave at 0 0

Left 4 Dead 2 Should you want a material that allows Envmaps with masks, Phong with mask, Detail and EmissiveBlend glows together, you may use this premade material:

VertexLitGeneric
{
	//Textures
	$baseTexture 				baseTexture_with_envmap_mask	//alpha mask is the envmap mask
	$bumpmap 					bumpmap_with_phong_mask			//alpha mask contains mask for phong.

	//Envmap Stuff
	$basealphaenvmapmask 		1					
	$envmap 					env_cubemap

	//Phong Stuff
	$phong 						1
	$phongboost 				10
	$phongexponent 				1
	$phongfresnelranges 		"[.1 .4 2]"	
	
	//Glow Stuff
	$EmissiveBlendEnabled 		1					
	$EmissiveBlendStrength 		1 					
	$EmissiveBlendTexture 		vgui/white			
	$EmissiveBlendBaseTexture 	Glow_texture_color	//change this to your desired static glow.
	$EmissiveBlendFlowTexture 	vgui/white	 		
	$EmissiveBlendTint 			" [ 1 1 1 ] "		
	$EmissiveBlendScrollVector 	" [ 0 0 ] " 		

	//Detail Stuffs
	$detail 					"models/infected/hunter/hunter_01_detail.vtf"
	$detailscale 				"1.75"
	$detailblendfactor 			1 
	$detailblendmode 			0
	$detailAmount 				0
}

Flowing

This is an example of a flowing $emissiveblend texture. It will appear like as if water is flowing across a model.

$EmissiveBlendEnabled 		1						// Enable EmissiveBlend. Like $selfillum 1	
$EmissiveBlendStrength 		1 						// how strong the entire glow effect is.
$EmissiveBlendTexture 		Glow_texture_color		// this is the glowing texture.vtf
$EmissiveBlendBaseTexture 	Glow_texture_mask		// This is the glowing texture's mask, like $selfillummask.  SHOULD BE VTF i8 FORMAT, NOT DXT5!!!
$EmissiveBlendFlowTexture 	Glow_texture_mask_flow	// EmmisiveBlend can "flow" or move. This here is the flowmap used, just like water.
$EmissiveBlendTint 			" [ 1 1 1 ] "			// RGB glow intensity. Leave at 1 1 1. This can be used to change how strong each color should glow. So instead of using a darker red color, you may use [.5 1 1] to have red glow half as strong.
$EmissiveBlendScrollVector 	" [ 0 0 ] " 			// makes the EmmissiveBlend flow in either direction if a proper EmissiveBlendFlowTexture were set. But ours is static, so leave at 0 0

Using envmaps for a Solid-Color Glow

If for some reason you can't use $selfillum and can't do glow with $detail, you can still do a solid-color glow on the material. As reflections are not affected by lighting and appear to glow in the dark, specular reflections using cubemaps can be used. Unlike $selfillum, you can only make pixels glow in a color additively, i.e., you can't make part of a texture glow, only add a single-color glow over it. Can be done using a white cubemap and making the cubemap reflection visible only in some places per-pixel through an $envmapmask. You can also tint the cubemap glow to any color by $envmaptint.

.rad files

Main article:  RAD file

example\exampletexture 128 192 96 400

Unlike $selfillum or the UnlitGeneric shader, lights of the specified color and brightness are generated in front of the world brush's face during VRAD complation. The brightness of the created lights is also affected by the density of the lightmap. Higher densities will produce a greater effect. The texture itself does not become fullbright, but the lights in front often make it seem so.

If a texture is specified in multiple places, it will be overridden by the latest information. If both lights.rad and <mapname>.rad specified the same texture, but <mapname>.rad was brighter, the light emitted in the compiled map would be the brighter <mapname>.rad version.

A .rad texture in use

More info on how this light system works can be found here.

UnlitGeneric Textures

The UnlitGeneric shader forces the entire face to be fullbright. The surface does not emit light, and light has no visible effect on the surface. Mainly used when the texture should appear to be a light source without forcing any light into creation. All that is required for the effect is to specify the materials shader as UnlitGeneric. Because UnlitGenerics are their own shader, they can be applied to both models and world brushes.

UnlitGeneric
{
	$basetexture example\exampletexture
}

A common use is that of skybox textures, the sky is always bright and the face the texture will appear on has no form of lighting itself.

Warning:You need to include the command $model 1 in your .vmt if you're using an UnlitGeneric on a model, otherwise the surface may not show up.

A unlitgeneric texture in use

_minlight

_minlight changes. From left to right: 0 (default), 0.5, 2, 10, 25, and 50

All lightmapped brush entities, as well as worldspawn, support the _minlight KV ("Minimum Light Level" in some FGD entries), which controls the minimum amount of of ambient light to add to the contained lightmaps. This is not strictly a glowing texture per se but another way that a texture can be made to appear to glow (without shedding any actual light). Setting high (from 5 to 50 or more, depending on how light the texture is) will result in the textures on the brush glowing brightly.

Warning:Increasing _minlight can have a disproportionate effect on cubemap sampling, causing the scene to compile too brightly.

Note:Psuedo-entities which collapse to worldspawn, such as func_detail and (in games before ) func_ladder, use worldspawn's _minlight value in stock compilers, as they are part of worldspawn by the time VRAD runs.

Code Fix:Custom compilers could circumvent this limitation by having the custom VBSP write additional metadata next to the BSP, which is read by the custom VRAD. This is what ericw-tools does. It would also make it easy to add minlight support to per-vertex-lit and lightmapped prop_static entities, without making compatibility-breaking changes to the static prop lump in the BSP.

info_lighting

Models can be made to glow brightly (though they do not actually emit any light) if their lighting origin key value is set to the name of an info_lighting that is placed in a lightbox isolated from the rest of the map. In the illustration to the right, the model to the right has been linked to an info_lighting placed in a small hollow cube with nine light entities, each set to a brightness of 5000.

One possibly-useful feature of this method of manipulating lighting is that it dynamically updates in real time. That is, if the lights in the lightbox are linked to a switch or trigger, or pre-set to pulse, flicker, or so on, the lighting on the model will reflect these changes immediately. This might be used, for instance, to slowly darken modeled terrain to simulate the coming of evening.

Note:Use info_lighting for static props only. For dynamic props, use an active edict entity (info_target if necessary).