Ridged multifractal noise: (offset - |perlin|)^2 summed over octaves with multiplicative
carry-over from the previous octave. Useful for sharp mountain ridges.
Parameters
x: number
y: number
z: number
lacunarity: number
frequency multiplier between octaves (typically ~2)
gain: number
amplitude multiplier between octaves (typically ~0.5)
offset: number
ridge offset, controls the height of the ridges (typically ~1)
Ridged multifractal noise:
(offset - |perlin|)^2summed over octaves with multiplicative carry-over from the previous octave. Useful for sharp mountain ridges.