Implementing a Fur Shader

The look of a material depends on its physical structure. The shaders attempt to simulate them, but in doing so, they oversimplify the way light behaves. Materials with a complex macroscopic structure are particularly hard to render. This is the case for many textile fabrics and animal furs. This recipe will show you how it is possible to simulate fur and other materials (such as grass) that are more than just a flat surface. In order to do this, the same material is drawn multiple times over and over, increasing its size every time. This creates the illusion of fur.

The shader presented here is based on the work of Jonathan Czeck and Aras Pranckevičius:

Getting ready

In order for this recipe to work, you will need two things. The first one is the texture of the fur as it appears from the outside. The second texture will be used to control the distribution of the fur and is deeply connected to the original one. The following image shows a leopard fur (left) and possible...