Noise is the secret ingredient behind clouds, terrain, fire, and nearly every organic-looking shader effect. It starts with a hash function that turns any coordinate into a pseudo-random number. Value noise smoothly blends between those random samples so there are no harsh jumps. FBM (Fractal Brownian Motion) layers multiple octaves of noise at increasing frequency and decreasing amplitude, building up rich, natural detail — like the difference between smooth hills and rugged mountains.
Key Concepts
hash function
value noise
smooth interpolation
FBM octaves
Try this shader live in the Shader Sandbox editor with real-time preview.