Chapter 10: Game Physics - Keeping It Real

Overview

One thing that can make or break the believability of a game is the physics implementation. Physics is the science of the physical world. It provides the mathematical representation of all dynamic objects. Through this math, we can determine how an object should move realistically .

This chapter will explore two applications of physics. The first is the dynamics involved within an automobile. This will include the interactions between the wheels, the ground, and the suspension, which, coupled with a simulation of an engine and transmission, provides a simple but believable simulation of a car for our racing game.

The second application of physics for our game engine will be an example of the physics of cloth. The math behind the simulation of cloth may be applied to flexible systems within a game such as flags, clothing, hair, and even grass. We will apply this type of physics to a rectangular section of cloth for use as a flag that flutters as the force of wind passing along it interacts with the cloth.

Physics is an extensive and diverse subject. We can only touch on a small part of the subject in this chapter. Entire books have been devoted to this subject, and additional books and online resources for physics can be found by searching the Web. A recent online search for game physics returned over 2000 entries. Another search for vehicle dynamics returned over 14,000 entries. If you are serious about applying physics within your games , I highly recommend that you think of this text as simply a springboard and that you do further research into this vast subject. For instance, one of the many links that I have found takes you to an interesting article that explains the physics behind the ballistics of a projectile (http://www.pixelate.co.za/issues/3/3/articles/game_physics/intro.htm).