$ambientocclusion: Difference between revisions
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Note:Ambient Occlusion maps seem to be used exclusively for eyes and sometimes faces/heads.
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[[Image:valveao.jpg|thumb|Various ambient occlusion maps found in Valve games for eyes and face.]] | |||
Ambient occlusion is a shading method which helps add realism to local reflection models by taking into account attenuation of light due to occlusion. Unlike local methods like Phong shading, ambient occlusion is a global method, meaning the illumination at each point is a function of other geometry in the scene. However, it is a very crude approximation to full global illumination. The soft appearance achieved by ambient occlusion alone is similar to the way an object appears on an overcast day. | Ambient occlusion is a shading method which helps add realism to local reflection models by taking into account attenuation of light due to occlusion. Unlike local methods like Phong shading, ambient occlusion is a global method, meaning the illumination at each point is a function of other geometry in the scene. However, it is a very crude approximation to full global illumination. The soft appearance achieved by ambient occlusion alone is similar to the way an object appears on an overcast day. | ||
{{note|Ambient Occlusion maps seem to be used exclusively for eyes and sometimes faces/heads.}} | |||
== Using Ambient Occlusion == | == Using Ambient Occlusion == | ||
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:<code>$AmbientOcclColor "[.n .n .n]"</code> - Replacing n with a number of the color (RGB format) | :<code>$AmbientOcclColor "[.n .n .n]"</code> - Replacing n with a number of the color (RGB format) | ||
:<code>$AmbientOcclTexture "path/to/vtf"</code> - Filename of the ambient occlusion texture to use | :<code>$AmbientOcclTexture "path/to/vtf"</code> - Filename of the ambient occlusion texture to use | ||
{{TODO|How does <code>$ambientocclusiontexture</code> fit in with all of this?}} | |||
== See also == | == See also == | ||
Revision as of 04:08, 13 August 2010
Ambient occlusion is a shading method which helps add realism to local reflection models by taking into account attenuation of light due to occlusion. Unlike local methods like Phong shading, ambient occlusion is a global method, meaning the illumination at each point is a function of other geometry in the scene. However, it is a very crude approximation to full global illumination. The soft appearance achieved by ambient occlusion alone is similar to the way an object appears on an overcast day.
Note:Ambient Occlusion maps seem to be used exclusively for eyes and sometimes faces/heads.Using Ambient Occlusion
Example VMT Syntax
The following example is taken from Left 4 Dead from the model material located in L4D root/materials/models/survivors/teenangst/teenangst_eyeball_l.vmt
EyeRefract
{
$Iris "models/survivors/green_iris2"
$AmbientOcclTexture "models/survivors/survivor_eye_ao"
$Envmap "Engine/eye-reflection-cubemap-"
$CorneaTexture "Engine/eye-cornea"
$EyeballRadius "0.6"
$AmbientOcclColor "[.4 .4 .4]" Default 0.33, 0.33, 0.33
$Dilation ".5"
$ParallaxStrength "0.25"
$CorneaBumpStrength ".5"
$halflambert 1
$nodecal 1
$ambientocclusion 1
$RaytraceSphere 1
$SphereTexkillCombo 0
}
VMT Paremeters
The following is a list of VMT parameters that are needed to enable the Ambient Occlusion:
$AmbientOcclusion "0/1"- Disable/Enable Ambient Occlusion. (1 = enabled, 0 = disabled)$AmbientOcclColor "[.n .n .n]"- Replacing n with a number of the color (RGB format)$AmbientOcclTexture "path/to/vtf"- Filename of the ambient occlusion texture to use
Todo: How does
$ambientocclusiontexture fit in with all of this?
See also
- Phong materials
- $basetexture
- $envmapmask (specular mask)
- $envmap (environment map)
- $selfillum