Book Image

Game Physics Cookbook

By : Gabor Szauer
Book Image

Game Physics Cookbook

By: Gabor Szauer

Overview of this book

Physics is really important for game programmers who want to add realism and functionality to their games. Collision detection in particular is a problem that affects all game developers, regardless of the platform, engine, or toolkit they use. This book will teach you the concepts and formulas behind collision detection. You will also be taught how to build a simple physics engine, where Rigid Body physics is the main focus, and learn about intersection algorithms for primitive shapes. You’ll begin by building a strong foundation in mathematics that will be used throughout the book. We’ll guide you through implementing 2D and 3D primitives and show you how to perform effective collision tests for them. We then pivot to one of the harder areas of game development—collision detection and resolution. Further on, you will learn what a Physics engine is, how to set up a game window, and how to implement rendering. We’ll explore advanced physics topics such as constraint solving. You’ll also find out how to implement a rudimentary physics engine, which you can use to build an Angry Birds type of game or a more advanced game. By the end of the book, you will have implemented all primitive and some advanced collision tests, and you will be able to read on geometry and linear Algebra formulas to take forward to your own games!
Table of Contents (27 chapters)
Game Physics Cookbook
Credits
About the Author
Acknowledgements
About the Reviewer
Acknowledgements
www.PacktPub.com
Customer Feedback
Preface
Index

Bounding Box in frustum


To test if an Oriented Bounding Box (OBB) or an Axis Aligned Bounding Box (AABB) intersects a frustum, follow the same steps. First we have to be able to classify the box against a plane. A box and a plane can have one of three intersection states:

  • The box is in front of the plane

  • The box is behind the plane

  • The box intersects the plane

Once we are able to classify a box to a plane, we need to loop through every plane of the frustum and classify the box against each plane. If the box is fully behind any of the six planes, there is no intersection. If the box is in front of every plane, it is contained within the frustum. Otherwise, the box intersects the frustum:

Getting ready

In this section, we are going to implement two Classify functions. One to classify an OBB against a plane, and one to classify an AABB against a plane. The Classify functions will have the following return values:

  • If the box is behind the plane, the negative distance is returned

  • If the box is in front...