Cellular
Description
A cellular noise function.
The noise value is computed using the distances of the given point to the four nearest feature points by combining them according to the specified coefficients:
result := (a0 * f0 + b0) * f0 + (a1 * f1 + b1) * f1 + (a2 * f2 + b2) * f2 + (a3 * f3 + b3) * f3 + c f0 := distance to 1st nearest feature point f1 := distance to 2nd nearest feature point f2 := distance to 3rd nearest feature point f3 := distance to 4th nearest feature point