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

Axis Aligned Bounding Box

An Axis Aligned Bounding Box (AABB) is the 3D version of a rectangle. We will define a 3D AABB by a center point (position) and a half extent (size). The half extent of an Axis Aligned Bounding box represents half of the width, height and depth of the box. For example a box with half extents of (2, 3, 4) would be four units wide, six units tall and eight units deep.

Getting ready

We are going to create a new AABB structure, which will contain an origin and half extents. It's helpful to be able to get the minimum and maximum points of an AABB. We are going to implement helper functions to get both the min and max point of a given AABB. We are also going to implement a helper function to create an AABB given a min and a max point.

How to do it

Follow these steps to implement a 3D Axis Aligned Bounding Box:

  1. Define the AABB structure in Geometry3D.h:

    typedef struct AABB {
       Point origin;
       vec3 size;
       inline AABB() : size(1, 1, 1) { }
       inline AABB(const Point&...