OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Definition of Noise

The purpose of this section is to provide a definition and enough of an intuitive feel that you can grasp the noise-based OpenGL shaders presented in this section and then use GLSL to create additional noise-based effects.

As Ken Perlin describes it, you can think of noise as “seasoning” for graphics. It often helps to add a little noise. A perfect model looks a little less perfect and, therefore, a little more realistic if some subtle noise effects are applied.

The ideal noise function has the following important qualities that make it the valuable tool we need for creating a variety of interesting effects, needed for successful use in modeling, rendering, or animation:

• It does not show any obvious regular or repeated patterns. ...