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

Oriented rectangle

An oriented rectangle is very similar to a non-oriented (Axis Aligned) rectangle. They both have a Position and a size, but the oriented rectangle also has a Rotation. Rotating a rectangle will allow us to better approximate the shape of objects as shown in the following diagram:

Getting ready

Unlike the Rectangle2D, we're going to represent an OrientedRectangle using a center point and half-extents. Additionally, we're also going to store a Rotation. It makes no sense for an oriented rectangle to have a min or max, so we're not going to implement these helper functions for the OrientedRectangle structure.

The reason we represent the rectangle this way is because it will make rotating objects relative to the rectangle easier. As an added bonus, by doing this we will have covered all three methods described earlier to represent a rectangle.

How to do it…

Follow these steps to create an oriented rectangle:

  1. Start the declaration of the OrientedRectangle structure in Geometry2D...