VII.1 - Wave Generators for Computer Graphics

Abstract

This chapter describes wave generators for computer graphics. The work of Perlin shows that combining simple generic operators (for example, noise, turbulence, bias, gain) allows the creation of complex specific visual effects such as marble, fire, or water. Though first presented as a procedural approach to texturing, the ideas have been generalized to many computer graphics applications, including modeling, deformation, rendering, and animation. This chapter provides several wave generators that represent some basic tools for creating many regular or random visual effects in computer imagery. The chapter discusses noise. It highlights that the most ubiquitous operator is the noise function. It generates a distribution having a user-controlled randomness while maintaining valuable statistical properties of invariance under translation or rotation and limited spectrum bandpass. Several implementations of the noise function have been proposed since its original development; a remarkably elegant recursive implementation has been discussed. Because the original noise routine was intended for solid texturing, it is often implemented as a 3D function that maps a point on the Euclidian space R3 onto a scalar value on the unipolar or bipolar interval [0,1] or [−1,1].