Texture and reflection in computer generated images

Abstract

In 1974 Ed Catmull developed a new algorithm for rendering images of bivariate surface patches. This paper describes extensions of this algorithm in the areas of texture simulation and lighting models.The parametrization of a patch defines a coordinate system which is used as a key for mapping patterns onto the surface. The parametric values within each picture element are input to a pattern definition function. A weighted average of the values of this function over the picture element scales the intensity of that picture element. By suitably defining the pattern function, various surfaces textures can be simulated. The shape and size of this weighting function is chosen using digital signal processing theory.The other problem addressed here concerns lighting models. The patch rendering algorithm allows accurate computation of the surface.