Beginning 3D Game Programming

Vectors

You've seen vectors already within this book, and it's possible you think that they are simply a representation of a point in space, such as a vertex. Although it's true that the vector can store this information, it does so in the DirectX API mainly for a convenience. The mathematical definition of a vector is an object that denotes both direction and velocity (or magnitude). For example, if you fire a bullet out of a tank (for which you will write code in the next game), that bullet has both a direction and a velocity. They are stored in one vector, which incidentally has the same members as a vertex, namely x, y, and z components. You're probably thinking, wait, how can you specify these two things with a single set of three coordinates? ...