Game Development Reference
using the overloaded operator forms of + and * wedefinedearlier.Infactthisisexactly
the purpose of our addScaledVector method, so we can write
and have it done in one operation, rather than taking the risk that our compiler will
decide to create and pass around extra vectors on the stack.
We now have almost all the mathematics we need for the particle engine imple-
mentation. We will implement the integration step in the next chapter, after we look
at the physics involved in simulating particles.
Vectors form the basis of all the mathematics in this topic. As we've seen, they are
easy to manipulate numerically and through simple routines in code. It is impor-
tant to remember, however, that vectors are geometrical: they represent positions and
movements in space. It is very often much simpler to understand the formulae in this
book in terms of their corresponding geometric properties rather than look at them
Describing positions and movements in terms of vectors is fine, but to make a
physics engine we'll need to begin to link the two. That is, we'll have to encode into
our physics engine the laws of physics that say how position and movement and time
are connected. This is the subject of chapter 3.