This shader is a function that perturbates the normal of a surface using noise(). Any other shader can be used to do the final shading calculations.
shaderhandle is a handle to another shader and surface specification.
scale describes how much the texture coordinates should be scaled before applying the texture. The larger the scaling, the smaller the area of the texture associated with a given area of the surface. A large number results in a very fine pattern, a small number yields a coarse pattern.
BUMPS indicates that only bumps standing out from the surface are visible, the rest of the surface is smooth.
HOLES indicates that only bumps going into the surface are visible, the rest of the surface is smooth. If neither HOLES or BUMPS or specified, then both are assumed to be on.