$phong

$phong is a material shader parameter for the VertexLitGeneric shader available in all Source games since Source 2006.

Phong shading provides Alyx's skin, hairband and lip highlights.

It is also available on the LightmappedGeneric and WorldVertexTransition shaders in all games since Counter-Strike: Global Offensive(also in ). It provides  diffuse reflections at low intensity and  specular highlights at apex intensity, masked by a texture which control per-texel its intensity. For a full explanation, see Phong materials.

Note:Phong shading for LightmappedGeneric and WorldVertexTransition is only available in . It requires the material to be lit by the sunlight from a env_cascade_light entity to work properly and uses the dynamic shadows generated by it as a mask on top of the traditional phong masking. ((in all games since ) env_projectedtexture also affects brushes with phong enabled)

Bug: Garry's Mod reads lighting direction for brush phong from env_sun instead; maps with multiple suns may not get accurate phong reflections on brushes.

Note:Phong shading for LightmappedGeneric is also available in Mapbase, but it is implemented differently.

Important:In all Source Engine games since Source 2007 (until ) enabling this shader will also enable $halflambert automatically (including gbuffer's halflambert in Black Mesa), unless $phongdisablehalflambert(in all games since ) is used. This effect isn't physically accurate, so it should be disabled if possible in most cases.

Bug:Phong reflection vectors are broken on static props with vertex lighting.  (tested in: ,)

Tip:Use new specular shader in Black Mesa as an alternative of phong on brushes.

Syntax

$phong <bool>

Note:All parameters in the following example must be specified in the material, otherwise Phong shading won't show up at all, except in Insurgency.

Todo: Other games that don't require all phong parameters present (likely Portal 2 and up)

VertexLitGeneric
{
	$phong 1

	$bumpmap				[texture]
	$phongexponent			5			// either/or
	$phongexponenttexture	[texture]	// either/or
	$phongboost				1.0
	$phongfresnelranges		"[0 0.5 1]"
}

Parameters

Masking

Warning:There are some caveats regarding $normalmapalphaenvmapmask and $selfillumfresnel when using $phong!

• Using $selfillumfresnel without $normalmapalphaenvmapmask will mask the $envmap using the $basetexture's alpha channel.
• Using $selfillumfresnel with $normalmapalphaenvmapmask will multiply the $envmap by 0.0f. Effectively disabling the effect!
• When not using $selfillumfresnel. The mask used for $envmap will be the $basetexture's alpha channel unless $normalmapalphaenvmapmask is also used.
• If $normalmapalphaenvmapmask is used, the $bumpmap's alpha channel will be used for Phong masking. Using either $basemapalphaphongmask or $basemapluminancephongmask will override it.

$bumpmap $basemapalphaphongmask $basemapluminancephongmask $phongexponent $phongexponenttexture $phongexponentfactor $invertphongmask $forcephong $diffuseexp $shinyblood $shinybloodexponent

Brightness

$phongboost $phongfresnelranges $phongdisablehalflambert

Colors

$phongalbedotint

An example model showing how AlbedoTint appears on a model.

$phongalbedoboost

The Hunter without and with its $phongwarptexture, showing how it affects the Phong reflection.

$phongtint

Breakdown of the $phongwarptexture: computed coordinates, texture and result

$phongwarptexture

Brush phong in Counter-Strike: Global Offensive using tile/hr_t/inferno/tile_a. Note the complete absence of the reflection in the shaded area.

Brush Shader Parameters

(only in )(also in )

$phongmaskcontrastbrightness $phongamount $phongbasetint

Console Commands

Cvar/Command	Parameters or default value	Descriptor	Effect
mat_phong	1	bool	Disable or enable phong shading. Bug:Doesn't work in Counter-Strike: Global Offensive branch.  (tested in: )

See also

• Phong materials
• $envmap (environment map)
• $lightwarptexture
• $rimlight

External links

• A comprehensive YouTube video on how phong materials work in Source
• $Phong on brushes*: The Hacky Way - A TF2maps.net guide on how to fake $Phong on brushes for games prior to CS:GO. Can also be used to fake phong on static props which are lit per-vertex, without falling back to lower-quality point lighting on the main prop
• SubstancePainter Source Engine Complex Phong Shader