David M Bourg - Physics for Game Developers: Science, math, and code for realistic effects

Most people that weve talked to when we was developing the concept for this book immediately thought of flight simulators when the phrases real physics and real-time simulation came up. Certainly cutting edge flight simulations are relevant in this context; however, many different types of games, and specific game elements, stand to benefit from physics-based realism.

Consider this example: Youre working on the next blockbuster hunting game complete with first-person 3D, beautiful textures, and an awesome sound track to set the mood, but something is missing. That something is realism. Specifically, you want the game to feel more real by challenging the gamers marksmanship, and you want to do this by adding considerations such as distance to target, wind speed and direction, and muzzle velocity, among others. Moreover, you dont want to fake these elements, but rather, youd like to realistically model them based on the principles of physics. Gary Powell, with MathEngine Plc, put it like this The illusion and immersive experience of the virtual world, so carefully built up with high polygon models, detailed textures and advanced lighting, is so often shattered as soon as objects start to move and interact.[] We think both these guys or right on target. Why invest so much time and effort making your game world look as realistic as possible, but not take the extra step to make it behave just as realistically?

Here are a few examples of specific game elements that stand to benefit, in terms of realism, from the use of real physics:

This is by no means an exhaustive list, but just a few examples to get you in the right frame of mind, so to speak. Pretty much anything in your games that bounces around, flies, rolls, slides, or isnt sitting dead still can be realistically modeled to create compelling, believable content for your games.

So how can this realism be achieved? By using physics, of course, which brings us back to the title of this section, the subject of mechanics . Physics is a vast field of science that covers many different, but related subjects. The subject most applicable to realistic game content is the subject of mechanics, which is really whats meant by real physics.

By definition, mechanics is the study of bodies at rest and in motion, and of the effect of forces on them. The subject of mechanics is subdivided into statics , which specifically focuses on bodies at rest, and dynamics , which focuses on bodies in motion. One of the oldest and most studied subjects of physics, the formal origins of mechanics can be traced back more than 2000 years to Aristotle. An even earlier treatment of the subject was formalized in Problems of Mechanics , but the origins of this work are unknown. Although some of these early works attributed some physical phenomena to magical elements, the contributions of such great minds as Galileo, Kepler, Euler, Lagrange, dAlembert, Newton, and Einstein, to name a few, have helped develop our understanding of this subject to such a degree that we have been able to achieve the remarkable state of technological advancement that we see today.