# Noise in Shaders → FBM

**Track:** Advanced Shaders & GPU — Advanced Creative Coding — proposed (50)
**Framework / surface:** GLSL
**Level:** Medium
**Prerequisites:** The Fragment Toolkit Beyond UV, Perlin Noise Fields

**In one line:** Hash/gradient noise and fractal Brownian motion layering.

## Theory, aesthetics & inspiration

Procedural texture starts from determinism disguised as chance: a hash function maps coordinates to repeatable pseudo-random values, which value noise interpolates between lattice points and gradient noise—Ken Perlin's 1985 contribution—smooths into the band-limited, organic field that defined a generation of CGI. Stacking octaves at halving amplitude and doubling frequency yields fractional Brownian motion, whose self-similar roughness models clouds, terrain, and smoke. The amplitude falloff tunes the result from soft haze to jagged ridges. Patricio Gonzalez Vivo's The Book of Shaders and Inigo Quilez's noise articles remain the canonical pedagogy, with Steven Worley's 1996 cellular noise an adjacent dialect; the look is soft, statistical, never repeating.