Perlin Noise Function for Unity
This is straight implementation of the Perlin noise function for Unity, which is based on Perlin's SIGGRAPH 2002 paper "Improving Noise".
You may use the script (Perlin.cs) in your projects freely.
The value range of the noise functions is [-1.0, +1.0].
AFAIK, the value range of the fBm functions is not well-defined. It might be
somewhere around [-0.75, +0.75]. Please let me know if you have the exact