Hughes/Computer Graphics, 3/E

Chapter 9. Functions on Meshes

9.1. Introduction

In mathematics, functions are often described by an algebraic expression, like f(x) = x² + 1. Sometimes, on the other hand, they’re tabulated, that is, the values for each possible argument are listed, as in

A third, and very common, way to describe a function is to give its values at particular points and tell how to interpolate between these known values. For instance, we might plot the temperature at noon and midnight of each day of a week; such a plot consists of 15 distinct dots (see Figure 9.1). But we could also make a guess about the temperatures at times between each of these, saying, for ...