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 plane and triangle

We have two planar primitives in our geometry toolbox, the Plane and the Triangle. The collision normal for both primitives is the same as the normal of the primitive itself. We must keep in mind that if a ray hits a plane or triangle from behind, that is not actually a hit. This is not a bug, it's how raycasting against these primitives should work. The "forward" direction of a triangle is determined by counter clockwise winding.

Getting ready

When we modify the Raycast API for a plane or a triangle we break all the functions that internally use the old declaration. We must take care to update these broken functions as well. We will need to update the Linetest against triangle function and the MeshRay function.

How to do it…

Follow these steps to update the Raycast function for both triangles and planes so that the functions return more useful data:

  1. Change the declaration of Raycast against both the Plane and Triangle in Geometry3D.h:

    bool Raycast(const Plane& plane...