$phong

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. 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 CS:GO engine branch. 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 4 also affects brushes with phong enabled)

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

Important:In Black Mesa half-lambertian for new lights is broken. The result is that meshes with $phong or $halflambert get lit from ALL sides perpendicular to newlights, including ones with opposing normals. If you want to use $phong or $halflambert - you are able to fix this with adding in your VMT material parameter "$halflambert_gbuffer_off" "1".

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 $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

mat_phong <booleanRedirectInput/boolean>

Disable or enable phong shading. Default 1.

See also

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

External links

• $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