$alphatest
$alphatest
is a material shader parameter available in all Source games. It specifies a mask to use to determine binary opacity. White represents fully opaque, while black represents fully transparent. Any values in-between are rounded to either 0 or 1. This effect is similar to $translucent
, except that it can not be semi-opaque, is much faster to render, and the engine can sort it properly when layered.
VMT syntax example
$alphatest <bool>
LightmappedGeneric { $basetexture glass\window001a $alphatest 1 $alphatestreference .5 $allowalphatocoverage 1 }
Additional parameters
$alphatestreference
<float>
- Specifies the minimum color value of the alpha channel in which the effect is rounded to 255. A value of ".3" will create a thicker shape while a value of ".7" will create a thinner shape.
Bug:
$alphatestreference
cannot be updated in real time with proxies.Tip: This limitation can be circumvented by using $alphatestreference 1, and modifying the
$alpha
value instead. (requires $alpha to be raised above 1, its normal threshold, this may cause sorting issues)$allowalphatocoverage
<boolean>
- Creates transparent steps based on alpha values. Can be used for softer edges. This parameter is incompatible with
$alphatestreference
. Note: MSAA must be enabled in order for this to have effect.
Comparison with $translucent
$translucent | $alphatest |
---|---|
Notice how the right circle hardly changes.
See also
$alpha
, for texture-wide translucency$distancealpha
, for vector-like alpha edges$vertexalpha
$translucent
, for per-pixel opacity.