Box2D for Flash Games

Emanuele Feronato

• Publisher: Packt Publishing
• Year: 2012
• eBook ISBN: 9781849519625
• Edition: 1
• Topic: Computer Science
• Subtopic: Computer Science General
• Index: Computer Science

In Detail

Physics games are getting more and more popular, and Box2D is the best choice if you are looking for a free, stable and robust library to handle physics. With Box2D you can create every kind of 2D physics game, only coding is not the fun part, but the game itself.

"Box2D for Flash Games" will guide you through the process of making a Flash physics game starting from the bare bones and taking you by hand through complex features such as forces, joints and motors. As you are learning, your game will have more and more features, like the physics games you are used to playing.

The book analyzes two of the most played physics games, and breaks them down to allow readers to build them from scratch in a step-by-step approach.

By the end of the book, you will learn how to create basic primitive bodies as well as complex, compound bodies. Motors will give life to cars, catapults and siege machines firing bullets, while a complete collision management will make your game look even more realistic.

If you want to make full Flash games with physics, then Box2D for Flash Games will guide you through the entire process of making a Flash physics game.

Approach

This book is a step by step guide to create games with Box2D explained in a simple and friendly way.

Who this book is for

Are you familiar with ActionScript3 and want to explore the capabilities of physics in game design using Box2D, then this book is for you. You don't have to be an AS3 hero: if you know how to create classes and functions with AS3, then you can make your first physics game!

Box2D for Flash Games

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Table of Contents

Box2D for Flash Games

Credits

About the Author

About the Reviewers

www.PacktPub.com

Support files, eBooks, discount offers and more

Why Subscribe?

Free Access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Hello Box2D World

Downloading and installing Box2D for Flash

Hello Box2D World

Defining the Box2D World

Running the simulation

Summary

2. Adding Bodies to the World

Your first simulation – a ball falling on the floor

Creating a circular shape

Creating a fixture

Using debug draw to test your simulation

Creating a box shape

Different body types – static, dynamic, and kinematic

Density, friction, and restitution

Creating a Totem Destroyer level

Creating compound bodies

Creating an oriented box shape

Creating any kind of convex polygons

Summary

3. Interacting with Bodies

Selecting and destroying bodies with a mouse click

Assigning custom attributes to bodies

Looping through bodies and getting their properties

Summary

4. Applying Forces to Bodies

Falling apples, revamped

Force, impulse, and linear velocity

Applying an impulse to get a linear velocity

Applying a force to get a linear velocity

Forces in a real game

Physics games aren't just a matter of physics

Placing the physics bird

Shooting the physics bird

Summary

5. Handling Collisions

Checking for collisions

Box2D built-in collision listener

Trace the beginning and the end of a collision

Detect when you are about to solve a collision and when you have solved it

Detecting when the idol falls on the floor in Totem Destroyer

Destroying bricks and killing pigs in Angry Birds

Summary

6. Joints and Motors

Picking and dragging bodies – mouse joints

Keeping bodies at a given distance – distance joints

Making bodies rotate around a point – revolute joints

When Angry Birds meets Crush the Castle

Controlling joints with motors

Controlling motors with keyboard

Don't let some bodies collide – filtering collisions

Putting it all together

Summary

7. Skinning the Game

Replacing debug draw with your own graphic assets

Summary

8. Bullets and Sensors

Experiencing tunneling

Preventing tunneling – setting bodies as bullets

Allow bodies to overlap while detecting contacts with sensors

Summary

Index

Box2D for Flash Games

Copyright © 2012 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: November 2012

Production Reference: 1161112

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-84951-962-5

www.packtpub.com

Cover Image by Artie Ng (<[email protected]>)

Credits

Author

Emanuele Feronato

Reviewers

Joseph Hocking

Ali Raza

Acquisition Editor

Mary Jasmine Nadar

Commissioning Editors

Priyanka Shah

Shreerang Deshpande

Technical Editor

Manmeet Singh Vasir

Copy Editor

Laxmi Subramanian

Project Coordinator

Shraddha Bagadia

Proofreaders

Maria Gould

Cecere Mario

Indexer

Hemangini Bari

Graphics

Aditi Gajjar

Production Coordinator

Prachali Bhiwandkar

Cover Work

Prachali Bhiwandkar

About the Author

Emanuele Feronato has been studying programming languages since the early 1980s, with a particular interest in game development. He taught online programming for the European Social Fund (ESF) and founded a web development company in Italy.

As a Game Developer, he has developed Flash games sponsored by the biggest game portals and his games have been played more than 70 million times, and he is now porting most of them on mobile platforms.

As a writer, he has worked as a Technical Reviewer for Packt Publishing and published the book Flash Game Development by Example, Packt Publishing.

His blog, www.emanueleferonato.com, is one of the most visited blogs about indie programming.

First of all I would like to give a big thank you to Erin Catto, the guy who developed Box2D, and to Boris the Brave for porting it to AS3.

A thank you also goes to Shraddha Bagadia and the entire Packt Publishing team for believing in this project, as well as to the reviewers for dealing with my drafts and improving the book.

The biggest thank you obviously goes to my blog readers and to my Facebook fans for appreciating my work, giving me the will to write more and more.

I also want to thank my wife Kirenia for being patient while I was writing rather than helping her to paint the house. Awesome job Kirenia!

About the Reviewers

Joseph Hocking is an interactive media developer living in Chicago. He has spent many years developing Flash games for various companies and freelance clients, and currently works for Synapse Games developing games such as Tyrant and Skyshard Heroes. His development skills include programming web-based games in AS3/Flash, using JavaScript in web pages, writing Python for both client and server applications, and building iPhone games using Lua/Corona SDK.

In addition, Joe also teaches at schools such as the Game Development program at Columbia College. Besides graphics programming, he has a great deal of training and experience in digital arts, including 3D animation. A portfolio of his work can be viewed at www.newarteest.com.

Ali Raza has a master's degree in Computer Science, and more than 8 years of experience as a Designer and Developer. He is also an Adobe Certified Instructor (ACI) and a Microsoft Certified Trainer (MCT).

He is currently working with a UK-based social networking startup as a Senior Developer (Flash Platform), and as a Consultant with a US-based firm ProContent, LLC (team behind Advanced Flash Components). In the past, he has worked with different ...

Table of contents

• Box2D for Flash Games