Only particles and decals are known to modify their vertex data, but it should be possible to implement your own scenarios too. Vertex alpha and color cannot be compiled into a model however, but they can be faked with an obscure shader named Modulate.
$vertexalphais needed in order to make the alpha parameter of
- Must be set to 1
- Must be set to 1 (This is not necessary on UnlitGeneric)
- The surface must be a displacement.
- You can use the "paint alpha" tool to paint the alpha.
There are some caveats.
- You can define a second base texture, but it will be invisible.
- $translucent Does not function. The material will continue to use the vertex alpha of the displacement. $additive however, does function normally
- Material renders as a translucent materials, and as such, suffers from the same sorting issues and caveats as materials with $translucent
To do: Are these commands shader-agnostic?