Aftershock

Aftershock is a pixel shader available in all Source games since Source 2007.

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January 2024

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It draws animated and scrolling refraction. It is able to smoothly fade out with alpha blending depending on its distance to the ground (per vertex; calculated with the material parameters $GroundMin and $GroundMax) and the dot product of the per vertex geometry normal and world view vector (scaled by $SilhouetteThickness). Furthermore this shader does solely support the vertexformat that studiomodels use.

Parameters

$normalmap <texture>

Normal map for the refraction.

$bumpframe <integer>

The frame to start an animated bumpmap on.

$bumptransform <matrix>

Transforms the bump map texture.

The default position is center .5 .5 scale 1 1 rotate 0 translate 0 0.

1. center defines the point of rotation. Only useful if rotate is being used.
2. scale fits the texture into the material the given number of times. 2 1 is a 50% scale in the horizontal X axis while the vertical Y axis is still at original scale.
3. rotate rotates the texture counter-clockwise in degrees. Accepts any number, including negatives.
4. translate shifts the texture by the given numbers. .5 will shift it half-way. 1 will shift it once completely over, which is the same as not moving it at all.

Note:All values must be included!

Bug:Scaling the texture may cause odd issues where the Texture Lock tool in Hammer will not actually lock the texture in place.  [todo tested in?]

Bug:Rotating textures applied on brushes will rotate around the map origin (confirm: Orangebox engine only?). A fix for this is to change the center position in the VMT to the brush's origin.  [todo tested in?]

$refractamount <float>

Controls the strength of the refraction by multiplying the normal map intensity.

$colortint <RGB matrix>

Todo: Color tint of the refraction?

$bluramount <float>

Adds a blur effect. Valid values are 0, 1 and 2.

$groundmin <float>

$groundmax <float>

Both describe an interval used to fade out the shader.

$silhouettecolor <RGB matrix>

Silhouette color tint.

$silhouettethickness <float>

Scales the generic fade amount along the models edge.

Time Proxy

For any reason, you may want to modulate time by scale it. The below material proxy is a simple sample to work properly.

Note: you don't need to declare "CurrentTime" Proxie in cases where you don't need to relative modify time scale.

	"$time" "0.0"
	"$CurrentTime" "0.0" // declare a custom VMT Parameter to "CurrentTime" Proxie output
	"$timeMult" "0.5"    // declare a custom VMT Parameter to use at "Multiply" Proxie

	"Proxies"
	{
		"CurrentTime"
		{
			// It pass CurrentTime Proxie to "$CurrentTime" variable to scale materials effects such $emissiveblendscrollvector.
			"resultVar" "$CurrentTime" 
		}
		"Multiply"
		{
			"srcVar1" "$CurrentTime" // get $CurrentTime VMT parameter to multiply with srcVar2
			"srcVar2" "$timeMult"    // get $timeMult VMT parameter to multiply with srcVar1
			"resultVar" "$time"      // writes multiplication product into $time, scaling "CurrentTime" 
		}
	}

Example

The only known material using this shader, found in Half-Life 2: Episode Two, materials/models/props_combine/sphere.vmt

"Aftershock"
{
	"<dx90"
	{
		"$fallbackmaterial" "models\props_combine\sphere_dx8"
	}

	"$normalmap" "models/props_combine/aftershock-normal"

	"$refractamount" "0.02"
	"$colortint" "[1.0 1.3 1.6]"

	"$SilhouetteThickness" "0.2"
	"$SilhouetteColor" "[0.3 0.3 0.5]"
	"$GroundMin" "-0.3"
	"$GroundMax" "-0.1"
	"$BlurAmount" "0.01"

	"$time" "0.0"
	"Proxies"
	{
		"CurrentTime"
		{
			"resultVar" "$time"
		}
	}
}

See also

• Refract
• Water

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