VEX Volume Cloud shader

This volume shader will shade volume objects as if they were fog. The density value will be used as the thickness of the fog at each point.

When attached to volume geometry, this shader will shade each point as if it were fog. The value of the volume geometry is used as a density value.

A uniform scale can be applied to the effective density using the Fog Density value. The Shadow Density is used when shadow rays are cast through the fog, allowing for the fog to be more or less opaque in the shadow pass.

Because the fog is sampled internally, default shadow shaders like Fast Shadow that return inside/outside will result in aliasing. If shadows do not need to cast on the fog, they can be turned off easily in this SHOP. Otherwise, one should use deep shadow maps or another method of getting soft shadows.