Editing Fast Fur Render Pipeline options (section)

== What is a "shader pipeline"? ==
GPU programs (ie. "shaders") aren't like regular programs. They run on the GPU, not the CPU. They are also massively parrallel, running hundreds or even thousands of copies of themselves at the same time.

The word "shader" is used inter-changeably to describe either an entire beginning-to-end shader pipeline (ie. "Warren's Fast Fur Shader"), or to describe the various self-contained stages of the pipeline (ie. a "Vertex shader", "Geometry shader", etc...).

The shader currently uses the Unity Built-in Render Pipeline (BiRP). This GPU pipeline consists of 4 programmable shader stages: Vertex, Hull + Domain, Geometry, and Fragment:
[[File:Unity BiRP.jpg|none|thumb|640x640px|The 4 programmable stages of the Unity BiRP.  The "Hull + Domain" and "Geometry" stages are optional.]]
Each shader stage processes the information it is given, then outputs the result. The GPU drivers are then responsible for transfering that output to the next stage, as well as performing non-programmable functions such as combining individual verticies into triangles, or trimming triangles that are only partially on-screen.

''(NOTE: The shader does not currently support Unity's other render pipelines, namely the Universal Render Pipeline (URP), High Definition Render Pipeline (HDRP), and Scriptable Render Pipeline (SRP). Future support for these pipelines is planned, but not until the shader is more polished, reliable, and feature-complete.)''

There are 3 different options for how the shader will use the available BiRP stages: