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

Vector matrix multiplication

We have now implemented translation, scaling, and rotation in terms of matrices. These matrices become useful when we can apply their transformations to vectors. How do we apply a matrix transformation to a vector? The same way we do to a matrix: using matrix multiplication!

To multiply a vector and a matrix, we need to think of a vector as a matrix that has only one row or column. This leaves us with an important question, is a vec3 a matrix with one column and three rows, or three columns and one row?

Row Vector

Column Vector

Pre Multiplication

Post Multiplication

If the vector is on the left side of the matrix, it's a 1 X 3 Row Vector. With a row vector, we use Pre Multiplication.

If the vector is on the right side of the matrix, it's a 3 X 1 Column Vector. With column vectors we use Post Multiplication.

The naming is intuitive, with pre multiplication the vector is placed before the matrix, with post multiplication the vector is placed after the matrix...