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

2D lines

A line is the shortest straight path that connects two points. A line can be defined by a point on the line and a slope; this is called the slope intercept form. An actual line has no ends; it extends infinitely in both directions. This is not what we intuitively think of as a line. Instead, we want to define a line using a Start Point and an End Point. This is called a Line Segment:

Getting ready

Even though we are implementing a line segment, in code we are going to refer to it as a line. We rarely, if ever, use real lines to detect collisions, but we often use line segments. The Line2D structure we are about to create will consist of two points, where the line starts and where it ends.

How to do it…

Follow these steps to define a two-dimensional line, and the helper functions we will need to work with lines:

  1. Define the Line2D structure in Geometry2D.h.

    typedef struct Line2D {
       Point2D start;
       Point2D end;
       inline Line2D() { }
       inline Line2D(const Point2D& s, const Point2D...