$phong

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

The $phong VMT command provides diffuse reflections. In most engine branches it is only available on VertexLitGeneric; Counter-Strike: Global Offensive (as of early 2015) allows it to a limited extent on LightmappedGeneric and WorldVertexTransition. For a full explanation, see Phong materials.

VMT syntax

$phong <bool>

Note:All parameters must be specified otherwise the phong shader won't show up at all, except in .

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

$bumpmap <texture>

There must be a Phong mask. The alpha channel of a bump map acts as a Phong mask by default.

$basemapalphaphongmask <bool>

Uses $basetexture's alpha channel as the Phong mask instead of $bumpmap's. The phong will not be influenced by the bumpmap, however.

Template:L4D add

Phong intensity is based on the brightness of $basetexture.

$phongexponent <int>

The numeric value overrides an exponent mask if present.

$phongexponenttexture <texture>

A global exponent value, or a per-texel exponent texture map. In an exponent map:

• Red channel: Exponent (size of highlight, 0-255, where a value of 0 is a large highlight, 255 small.)
• Green channel: Albedo tint (if $phongalbedotint 1, higher is more tint)
• Blue channel: Nothing
• Alpha channel: $rimlight mask

$invertphongmask <bool>

Appears to invert the value of the phong mask, as the name suggests.

Todo: What types of mask does this work on?

$phongexponentfactor <int>

This number will be used to multiply the exponent texture.

Template:L4D add

Template:L4D add

Todo: See Shading a Bigger, Better Sequel: Techniques in Left 4 Dead 2.

$diffuseexp

Todo: Does this have something to do with the $phongexponent, $phongexponenttexture or both? Confirm engine branches.

Brightness

$phongboost <float>

Phong brightness factor. Larger values create a more intense highlight, useful for surfaces like metal and glass.

$phongfresnelranges <matrix>

See Phong Fresnel ranges. Default is "[0 0.5 1]".

$phongDisableHalfLambert <bool> Template:P2 add

Used in Portal 2 on the Personality Cores such as Wheatley, disables functionality of $halflambert. MAY need $halflambert 0!

$ambientocclusiontexture <texture>

A "dirtmap". Mentioned in the SDK samples and seen in the VMT for Alyx's face. Ambient Occlusion is generally used for the eyes and face.

Todo: Does this actually do anything?

Colours

$phongalbedotint <bool>

Allows the $basetexture to affect the color of the Phong highlight. The amount of tint is defined by the green channel of $phongexponenttexture (see above).

Note:$phongalbedotint will tint highlights by the original color of the $basetexture even when the material is tinted by $color2 or rendercolor.

$phongtint "[<red float> <green float> <blue float>]"

Modifies the colour of the phong reflection. The channels are interpreted relative to each other (so "[0 0 0]" and "[1 1 1]" are the same).

Bug:This does not work with $basemapalphaphongmask.  [todo tested in ?]

$phongwarptexture <texture> Template:EP2 add

Used to create an iridescence effect, as seen on npc_hunters.

Todo: How does $phongwarptexture actually work?

Note:Does not work in , despite the game being released in 2009

Phong shading on brush faces

A May 2015 update to Counter-Strike: Global Offensive added limited support for Phong-based highlights on LightmappedGeneric materials. Currently it only works when the material is directly lit by an env_cascade_lighting, using the dynamic shadows as a mask (although traditional Phong masking is supported on top of this). It is known to work on displacements as well as WorldVertexTransition materials, but not on water or Lightmapped_4WayBlend.

New Parameters

$phongMaskContrastBrightness "[<float> <float>]"

Defines the contrast level between light and dark areas in the mask, and the overall brightness, respectively. Added along with support for phong-shaded lightmapped textures.

Todo: Find out the range of both values, and whether or not it can be used on models.

$phongAmount "[<red float> <green float> <blue float> <brightness> float]"

Controls the tint and brightness. The fourth value can go beyond 1, but affects the brightness of the whole texture, not just the highlight.

See also

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