Perlin noise is ubiquitous in modern CGI. Used for procedural
texturing, animation, and enhancing realism, Perlin noise has been
called the "salt" of procedural content. Perlin noise is a type of
gradient noise, smoothly interpolating across a pseudo-random matrix
of values.

The noise library includes native-code implementations of Perlin
"improved" noise and Perlin simplex noise. It also includes a fast
implementation of Perlin noise in GLSL, for use in OpenGL shaders.