Game Development Reference
Figure 8-4. Particles coming to rest on the ground plane
While working through this chapter, keep in mind that everything you're learning here
will be directly applicable to 2D and 3D simulations. Chapters following this one will
build on the material covered here. We'll focus on two dimensions in this chapter and
later in the topic we'll show you how to extend the simulation to 3D. Actually, for particle
simulations it's almost trivial to make the leap from 2D to 3D. Trust us on this for now.
Simple Particle Model
The particle model we'll begin with is very simple. All we want to achieve at first is to
have the particles fall under the influence of gravity. The particles will be initialized with
an altitude above a ground plane. Upon the start of the simulation, gravity will act on
each particle, continuously causing each to accelerate toward the ground plane, gaining
speed as it goes. Imagine holding a handful of small rocks up high and then releasing
them. Simple, huh?