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

Raycast Sphere

Given a ray with origin o, indirection d and a sphere with origin c and radius r; we want to check if the ray ever intersects the sphere:

If the ray intersects the sphere, this intersection will happen at some distance along the ray. Within the context of ray casting, we often assume it takes one second to travel one unit along the ray. Because of this, distance and time are often used interchangeably.

Because of this ambiguity with the vocabulary, many resources might say that the ray intersects the sphere at some time, t. If the ray does not intersect the sphere, t is undefined.

Getting ready

We are going to implement a function to check if a ray and a sphere intersect. This function will return t, the time along the ray at which the intersection takes place. If there is no intersection, we will set t to be a negative number.

How to do it…

Follow these steps to implement raycasting against a sphere:

  1. Declare the Raycast function in Geometry3D.h:

    float Raycast(const Sphere& sphere...