VEX Shadow Map shader

The shadowmatte shader generates an alpha image that stores screen-space shadow information for later compositing.

The shadowmatte shader will occlude geometry behind the surface being rendered, however, the output image will have the alpha value specified. This allows for compositing tricks. Where this surface is shadowed, the alpha of the output image will contain additional alpha. When the resulting image is composited over a background plate, the shadowed regions will occlude the background plate, simulating shadows. When the matte shader is hit by shadow rays, the shadow amount determines how much of a shadow will be cast by the surface.

It is also possible to disable fog on the surface. This means that no fog will show up on the surface.