$allowdiffusemodulation
$allowdiffusemodulation
is a material shader parameter available in all Source games since Left 4 Dead for
VertexLitGeneric
. It prevents a material from being tinted by either $color2
or the rendercolor
parameter. This is useful for situations where you have a model made up of multiple materials, some which you might want tint-able and some not.

$notint
in 
Syntax
$allowdiffusemodulation <bool>