Introduction to 3D Game Programming with DirectX 10

Appendix C

Some Analytic Geometry

In this appendix, we use vectors and points as building blocks for more complicated geometry. These topics are used in the book, but not as frequently as vectors, matrices, and transformations; hence, we have put them in an appendix rather than in the main text.

C.1 Rays, Lines, and Segments

A line can be described by a point p₀ on the line and a vector u that aims parallel to the line (see Figure C.1). The vector line equation is:

By plugging in different values for t (t can be any real number) we obtain different points on the line.

Figure C.1: A line described by a point p₀ on the line and a vector u that ...