Game Development Reference
tion, and then other collisions that would be affected were updated. Each algorithm
continued up to a fixed maximum number of iterations.
The resulting physics system is quite usable, and if you are following along writing
your own code, I recommend that you have a go at creating a demonstration program
and see the results. The simulation has no friction, so objects slide across one another.
For simple sets of objects it is likely to work fine. For more complex scenarios you may
notice problems with vibrating objects or slow performance.
We will address these three limitations in the next two chapters. Chapter 15 looks
at the difference between the collisions we have been dealing with so far and with rest-
ing contacts (this is part of the vibration problem). It also introduces friction. Once
friction is introduced, more stability problems become visible. Chapter 16 addresses
vibration and friction stability, and looks at some simple techniques for dramatically
improving the performance of the engine.