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

Octree culling

Now that we have a frustum and we can check said frustum for intersection against primitives, we can finally implement scene level culling. We will provide the Scene class with a Frustum object, the Scene class will return a list of Model objects. The OBB of each model within this list intersects the frustum. This way, we only need to consider objects for rendering, which the camera might see.

If a scene is spatially divided with an Octree, this method of culling should increase render time by eliminating non visible objects from being rendered. However, if a scene is not accelerated, and we just linearly test every object against the frustum we might actually make performance worse.

Getting Ready

We are going to add a new method named Cull to the existing Scene class. This new method will take a Frustum as an argument and will return a list of Model objects that intersect the frustum.

How to do it…

Follow these steps to cull the Octree of a Scene using a Frustum:

  1. In Scene.h, add...