Introduction to Computer Graphics

Chapter 4

Geometric Transformations

Geometric transformations come into play all the time in computer graphics, and to learn how to manipulate them correctly will save you hours of painful debugging. In this chapter, we will take an informal approach, starting from simple intuitive examples and then generalizing.

4.1 Geometric Entities

In computer graphics we deal with three entities: scalars, points and vectors. A scalar is a one-dimensional entity that we use to express the magnitude of something, for example the temperature of a body or the weight of a car. A point is a location in space, for example the tip of your nose, and a vector is a direction, for example the direction in which you are walking or the orientation of a satellite antenna. ...