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

Physics System Update

Now that we have a way to generate collision manifolds for colliding objects and a way to apply impulses to rigidbodies, we must make some modifications to the physics system to actually use these features. Most of this work will consist of modifying our physics loop, but we also need to add a few class variables.

As we are applying gravity to objects resting on each other, we might experience sinking. Sinking simply means that objects that should rest on top of each other sink through each other. We can fix this using Linear Projection. To perform linear projection, when a collision has happened, we will move both the objects a little along the collision normal. This slight adjustment to position will fix sinking problems for now.

We will update our physics loop to perform the following steps:

  • Find and store pairs of colliding rigidbodies

  • Accumulate forces acting on the rigidbodies

  • Apply impulses to resolve collisions

  • Update the position of every rigidbody

  • Correct sinking...