Table Of ContentEarly Praise for Create Mobile Games with Corona
It’s straightforward, it’s thorough, and it walks new users through all of the basics.
I especially like how the book explains full game templates for popular genres in
an easy-to-understand way.
➤ Brent Sorrentino, developer liaison at Corona Labs
I’ve wanted to make an iPhone game since the launch of the App Store, and now
I feel like I’m closer to my goal. The Corona SDK is a powerful tool, but good tuto-
rials are hard to find; I feel much more prepared having read Silvia’s book!
➤ Stephen Orr, lead developer at Made Media
Looking for a way into programming mobile devices? What could be more fun
than making a game (or three)? Create Mobile Games with Corona inspired me to
get a little further with an idea I had for a mobile app, and Corona offers lots of
speed and versatility for creating such things.
➤ Stephen Wolff, Django developer
Do you want to develop games for the Android platform? Look no further. This
book teaches you to create ready-to-distribute games in Lua in no time. Highly
recommended!
➤ Brian Schau, developer, Rovsing Applications
Create Mobile Games with Corona
Build with Lua on iOS and Android
Silvia Domenech
The Pragmatic Bookshelf
Dallas, Texas • Raleigh, North Carolina
Many of the designations used by manufacturers and sellers to distinguish their products
are claimed as trademarks. Where those designations appear in this book, and The Pragmatic
Programmers, LLC was aware of a trademark claim, the designations have been printed in
initial capital letters or in all capitals. The Pragmatic Starter Kit, The Pragmatic Programmer,
Pragmatic Programming, Pragmatic Bookshelf, PragProg and the linking g device are trade-
marks of The Pragmatic Programmers, LLC.
Every precaution was taken in the preparation of this book. However, the publisher assumes
no responsibility for errors or omissions, or for damages that may result from the use of
information (including program listings) contained herein.
Our Pragmatic courses, workshops, and other products can help you and your team create
better software and have more fun. For more information, as well as the latest Pragmatic
titles, please visit us at http://pragprog.com.
The team that produced this book includes:
Fahmida Y. Rashid and Aron Hsiao (editors)
Potomac Indexing, LLC (indexer)
Candace Cunningham (copyeditor)
David J Kelly (typesetter)
Janet Furlow (producer)
Juliet Benda (rights)
Ellie Callahan (support)
Copyright © 2013 The Pragmatic Programmers, LLC.
All rights reserved.
No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form, or by any means, electronic, mechanical, photocopying,
recording, or otherwise, without the prior consent of the publisher.
Printed in the United States of America.
ISBN-13: 978-1-937785-57-4
Encoded using the finest acid-free high-entropy binary digits.
Book version: P2.0—January 2014
Contents
Acknowledgments . . . . . . . . . . . ix
Preface . . . . . . . . . . . . . . xi
Part I — Getting Started
1. Hello, Corona! . . . . . . . . . . . . 3
1.1 A Word on Game Development 3
1.2 Getting Started with Corona 5
1.3 Building Our First App 10
1.4 What We Covered 13
Part II — Planet Defender
2. The Game Loop . . . . . . . . . . . . 17
2.1 What You’ll Learn 17
2.2 A Crash Course in Corona Programming 17
2.3 Designing Our First Game: Planet Defender 29
2.4 Creating the Project 30
2.5 Coding the Game Loop 32
2.6 What We Covered 37
3. Sprites and Movement . . . . . . . . . . 39
3.1 What You’ll Learn 39
3.2 Displaying Images 39
3.3 Animated Sprites 43
3.4 Handling Many Images 48
3.5 Moving Images 52
3.6 Adding Spaceships to the Game 56
3.7 Exercise: Modifying the Game 58
3.8 What We Covered 58
Contents • vi
4. Input and Menus . . . . . . . . . . . 59
4.1 What You’ll Learn 59
4.2 Touch-Based Input 59
4.3 Displaying Scenes Using the Storyboard API 63
4.4 Adding Buttons 66
4.5 Adding Lives and Difficulty 68
4.6 Exercises and Expansion Options 74
4.7 What We Covered 74
Part III — Vertical-Scrolling Shooter
5. Representing Movement and Perspective . . . . . . 79
5.1 What You’ll Learn 79
5.2 Designing a Basic Scroller 80
5.3 Adding Menus and the Basic Framework 80
5.4 Adding and Removing Units 81
5.5 Displaying Scrolling Backgrounds and Parallax Effects 90
5.6 Generating Random Backgrounds 94
5.7 Exercises and Expansion Options 97
5.8 What We Covered 98
6. Adding Shooting, Collisions, and Power-Ups . . . . . 99
6.1 What You’ll Learn 99
6.2 Shooting 99
6.3 Checking for Collisions 105
6.4 Adding Animated Explosions 111
6.5 Adding Power-Ups 115
6.6 Ending the Game 119
6.7 Exercises and Expansion Options 119
6.8 What We Covered 120
7. Adding Sound . . . . . . . . . . . . 121
7.1 What You’ll Learn 121
7.2 Finding Game Sounds 122
7.3 Understanding the Corona Sound API 122
7.4 Adding Sound Effects 123
7.5 Playing Background Music 130
7.6 Exercises and Expansion Options 134
7.7 What We Covered 135
Contents • vii
Part IV — Tower Defense
8. Displaying Maps and Sorting Depths . . . . . . 139
8.1 What You’ll Learn 139
8.2 Designing a Tower-Defense Game 140
8.3 Defining Tile-Based Maps 140
8.4 Building Towers 144
8.5 Sorting Depths in Corona 151
8.6 Exercises and Expansion Options 152
8.7 What We Covered 153
9. Adding Movement and Artificial Intelligence . . . . 155
9.1 What You’ll Learn 155
9.2 Adding Enemies 155
9.3 Implementing Enemy Movement 161
9.4 Adding Tower AI 171
9.5 Exercises and Expansion Options 185
9.6 What We Covered 185
10. Loading and Saving . . . . . . . . . . . 187
10.1 What You’ll Learn 187
10.2 Loading Levels 188
10.3 Loading and Saving the Game 194
10.4 Exercises and Expansion Options 202
10.5 What We Covered 203
Part V — Physics and Distribution
11. Physics and the Accelerometer . . . . . . . . 207
11.1 What You’ll Learn 207
11.2 Defining the Project 208
11.3 Adding User Input 212
11.4 Using the Accelerometer 214
11.5 Working with Removable Crates 216
11.6 Exercises and Expansion Options 219
11.7 What We Covered 220
12. Publishing Our Apps . . . . . . . . . . 221
12.1 What You’ll Learn 221
12.2 Building and Publishing Our Apps 221
Contents • viii
12.3 Testing on Our Phones 229
12.4 Selling In-App Features 231
12.5 Adding Advertisements 236
12.6 Exercise: Modifying the Game 237
12.7 What We Covered 238
A1. Corona Resources . . . . . . . . . . . 239
A1.1 Corona Development Tools 239
A1.2 Corona Development Environments 240
A1.3 Art Resources 241
A1.4 Game Sounds 242
A2. Classes in Corona . . . . . . . . . . . 245
Index . . . . . . . . . . . . . . 249
Acknowledgments
I would like to begin by thanking the artists who have made this book’s
projects possible. Without them, the demos would be limited to stick figures
created by an artistically challenged programmer. I am indebted to Daniel
Cook from Lost Garden for his 2D tile set;1 Cliff Harris from Positech Games
for his explosion generator;2 Lamoot and Luke.RUSTLTD from OpenGameArt,
who shared their user-interface assets and crates, respectively;3,4 and my
father, Gabriel Domenech, who painted the spaceships, planets, and back-
grounds used throughout the book. Thanks to Kibblesbob and Mike Koening
at SoundBible for their missile and bomb sounds and to Kevin MacLeod at
Incompetech for his Space Fighter Loop and Pinball Spring music loops.5,6
I must also thank the amazing community of developers who code using
Corona, as well as all the beta readers who caught numerous bugs and made
suggestions on the forums. This book also received lots of input from a great
group of technical reviewers: in no particular order, they are Brent Sorrentino,
Charley Stran, Javier Collado, Stephen Wolff, Al Scherer, Stephen Orr, and
Brian Schau. Of course, this book is what it is thanks to my editors, Fahmida
Y. Rashid and Aron Hsiao, both exceptional in different ways. Finally, thanks
to the Pragmatic Programmers for their wonderful writing workflow and
everything they do for the programming community...oh, and for letting me
write this book!
1. http://www.lostgarden.com
2. http://www.positech.co.uk
3. http://opengameart.org/users/lamoot
4. http://opengameart.org/users/lukerustltd
5. http://www.soundbible.com
6. http://incompetech.com/
report erratum • discuss
