Editing Fur Shader Passes (section)

== Pass 1 - The Skin ==
Many lighting effects, such as proper specular lighting and normal maps, are simply too slow to calculate for every layer of fur. As a compromise, my shader only renders the skin "expensively".

However, an unexpected benefit of rendering the skin separately is that it actually renders faster than doing everything in 1 pass. As far as I can tell (and this is really just a guess!), trying to render the opaque skin at the same time as the mostly see-through fur results in the GPU caches missing a lot.

The speed increase is so great, in fact, that 16 "cheap" fur layers + 1 "expensive" skin layer renders significantly faster than 15 "cheap" fur layers + 1 "cheap" skin layer.