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


To check if a Sphere and an Axis Aligned Bounding Box (AABB) intercept, we must first find the closest point on the AABB to the Sphere. Once we have this point, we can figure out the distance between the Sphere and the closest point. Finally, we can compare this distance to the radius of the Sphere. If the distance between the closest point and the Sphere is less than the radius of the Sphere, the point is inside the Sphere:

Getting ready

We are going to implement a function to test if a Sphere and an AABB are intersecting. We will also use a #define macro to implement a convenience function to see if an AABB intercepts a sphere. This macro just switches the function name and arguments.

How to do it…

Follow the given steps to implement sphere to AABB intersection testing:

  1. Declare SphereAABB in Geometry3D.h:

    bool SphereAABB(const Sphere& sphere, const AABB& aabb);
  2. Declare the AABBSphere macro in Geometry3D.h:

    #define AABBSphere(aabb, sphere) \
       SphereAABB(Sphere, AABB)
  3. Implement...