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

Point in triangle

We already have a definition for Triangle in Geometry3D.h, we implemented this primitive in Chapter 7, 3D Primitive Shapes . The first operation we want to perform on a triangle is testing for point containment. The containment test works by moving the triangle into the point's local space, then constructing a pyramid out of the triangle and the point. If the pyramid is flat, the point is inside the triangle. If it's not, the point is outside.

Getting ready

We are about to implement a function that will test if a point falls inside of a triangle. This function will return a simple boolean result.

How to do it…

Follow these steps to implement a point in triangle test:

  1. Declare the PointInTriangle function in Geometry3D.h:

    bool PointInTriangle(const Point& p, const Triangle& t);
  2. Implement the PointInTriangle function in Geometry3D.cpp:

    bool PointInTriangleNormals(const Point& p, 
    const Triangle& t) {
  3. Create a temporary triangle with the size of our original triangle...