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
About the Author
About the Reviewer
Customer Feedback

Rectangle to oriented rectangle

Testing a rectangle against an oriented rectangle is not as easy as one would expect. If we translate the rectangle into the oriented rectangles space, we would end up with the non oriented rectangle being oriented, and the oriented rectangle becoming non-oriented.

We can perform an SAT test between the two rectangles. We do not have to perform the generic version of the SAT which should involve twenty four24 axes of potential separation. We can reduce rectangle to orientd rectangle to four axes of potential separation:

  • The global X Axis (1, 0)

  • The global Y Axis (0, 1)

  • The oriented rectangles X axis (rotation.X, 0)

  • The oriented rectangles Y axis (0, rotation.Y)

Getting ready

First we are going to implement the support functions needed for an SAT test between a Rectangle and an OrientedRectangle. We already have all the support functions for the Rectangle implemented from the last section, now we have to implement these functions for the OrientedRectangle. These functions...