Vectors - Essentials of Interactive Computer Graphics - page 472

B

Vectors

This appendix is a review of basic vector math. It is assumed that you have worked
with vectors and matrices before. This chapter reviews the application of this
knowledge in computer graphics but is not meant as a full coverage of linear
algebra.

B.1 Vector Basics

The word “vector” is used for many different entities in different fields, and this
can make issues surrounding vectors confusing. For example, in computer graph-
ics, any one-dimensional array might be referred to as a vector. We however
restrict our use to mean a geometric entity we might think of as an arrow. The
main way we use vectors is as displacements, directions, and locations (points).
A displacement is sometimes called an offset and is a description of a distance
and direction. For example, if you point in a direction and say “10 meters that
way,” you have defined a vector. A direction is simpler in that it lacks a distance. It
is often represented as a unit-length displacement. A point, also called a location,
is defined in terms of some special location (e.g., the origin). Any point can be
defined in terms of an origin and a displacement.

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