@Override
    public void init() {

    }
FractalSum is the simplest form of fractal functions summing up a few octaves
of the noise value with an ever decreasing roughness (0 to 1) amplitude

lacunarity = 2.0f is the classical octave distance

Note: though noise basis functions are generally designed to return value
between -1..1, there sum can easily be made to extend out of this range. To
handle this is up to the user.

@author Anthyon
jme3-terrain/src/main/java/com/jme3/terrain/noise/fractal/FractalSum.java