Unity 3.x Game Development
by Example
Beginner's Guide
A seat-of-your-pants manual for building fun, groovy lile
games quickly with Unity 3.x
Ryan Henson Creighton
BIRMINGHAM - MUMBAI
Unity 3.x Game Development by Example
Beginner's Guide
Copyright © 2011 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system,
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Every eort has been made in the preparaon of this book to ensure the accuracy of the
informaon presented. However, the informaon contained in this book is sold without
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and distributors will be held liable for any damages caused or alleged to be caused directly or
indirectly by this book.
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Packt Publishing cannot guarantee the accuracy of this informaon.
First edion: September 2010
Second edion: September 2011
Producon Reference: 1160911
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ISBN 978-1-84969-184-0
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Cover Image by Dan Cox ( />Credits

Adventure, the game he authored with his ve-year-old daughter Cassie. Ryan maintains one
of the most acve and enjoyable blogs in the industry. He is also the author of the book that
you are currently reading.
When Ryan is not developing games, he's goong o with his two lile girls and his fun-
loving wife in downtown Toronto.
Big thanks to Cheryl, Cassandra, and Isabel for their love, their support,
and their cinnamon rolls. Thanks to Jean-Guy Niquet for introducing me to
Unity; to Jim "McMajorSupporter" McGinley for help with the book outline
and ongoing mentorship; to the technical reviewers and Packt sta for
leng me leave a few jokes in the book; and to David Barnes, for having
such a great sense of humor in the rst place. Special thanks to Michael
Garforth and friends from the #Unity3D IRC channel on Freenode. I also
want to thank Mom, God, and all the usual suspects.
About the Reviewer
Cliord Peters is currently a college student pursuing a degree in Computer Science. He
enjoys programming and has been doing so for the past 4 years. He enjoys using Unity and
hopes to use it more in the future.
Cliord has also helped to review the books Unity Game Development Essenals and Unity
3D Game Development Hotshot.
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Walk before you can run (or double jump) 17
There's no such thing as "nished" 18
Stop! Hammer me 18
Explore Bootcamp 19
The wonders of technology! 21
The Scene window 22
The Game window 22
The Hierarchy 23
The Project panel 24
The Inspector 25
Heads up? 26
Layers and layout dropdowns 28
Playback controls 28
Scene controls 29
Table of Contents
[ ii ]
Don't stop there—live a lile! 29
Summary 31
Big ambion, ny games 31
Chapter 2: Let's Start with the Sky 33
That lile lightbulb 34
The siren song of 3D 35
Features versus content 36
A game with no features 36
Mechanic versus skin 36
Trapped in your own skin 37
That singular piece of joy 37
One percent inspiraon 37
Motherload 38
Heads up! 40

Time for acon – Moving and rotang the light 69
Extra credit 72
Are you a luminary? 72
Who turned out the lights? 72
Darkness reigns 72
Time for acon – Camera mania 73
Time for acon – Test your game 73
Let's get physical 74
Time for acon – Adding physics to your game 74
Understanding the gravity of the situaon 75
More bounce to the ounce 76
Time for acon – Make the ball bouncy 76
Summary 79
Following the script 79
Chapter 4: Code Comfort 81
What is code? 81
Time for acon – Wring your rst Unity script 81
A leap of faith 83
Lick it and sck it 84
Disappear Me! 84
It's all Greek to me 84
You'll never go hungry again 85
With great sandwich comes great responsibility 86
Examining the code 86
Time for acon – Find the Mesh Renderer component 87
Time for acon – Make the ball re-appear 88
Ding! 89
Time for acon – Journey to the Unity Script Reference 89
The Renderer class 91
What's another word for "huh"? 94

Time for acon – Adding the sample code to your script 113
One nal tweak 115
What's a quaternion? 115
Wait, what's a quaternion? 115
WHAT THE HECK IS A QUATERNION?? 115
Educated guesses 116
More on Slerp 117
Right on target 117
Keep it up 119
Beyond the game mechanic 120
Chapter 5: Game #2: Robot Repair 121
You'll totally ip 122
A blank slate 123
You're making a scene 124
Time for acon – Seng up two scenes 124
No right answer 125
Time for acon – Preparing the GUI 126
The beat of your own drum 128
Time for acon – Creang and linking a custom GUI skin 128
Time for acon – Creang a buon UI control 130
Table of Contents
[ v ]
Want font? 134
Cover your assets 136
Time for acon – Nix the mip-mapping 137
Front and center 138
Time for acon – Centering the buon 138
To the game! 140
Time for acon – Adding both scenes to the Build List 141
Set the stage for robots 142

Pumpkin eater 179
Stabby McDragonpoker rides again 180
Table of Contents
[ vi ]
Game and match 180
Time for acon – ID the cards 180
Time for acon – Comparing the IDs 181
On to the nal boss 184
Endgame 184
Time for acon – Checking for victory 184
Endgame 187
Bring. It. On. 188
Chapter 7: Don't Be a Clock Blocker 193
Apply pressure 194
Time for acon – Preparing the clock script 194
Time for more acon – Preparing the clock text 195
Sll me for acon – Changing the clock text color 196
Time for acon rides again – Creang a font texture and material 197
Time for acon – What's with the ny font? 200
Time for acon – Preparing the clock code 201
Time for acon – Creang the countdown logic 202
Time for acon – Displaying the me onscreen 204
Picture it 207
Time for acon – Grabbing the picture clock graphics 207
Time for acon – Flexing those GUI muscles 209
The incredible shrinking clock 213
Keep your fork—there's pie! 214
How they did it 214
Time for acon – Rigging up the textures 216
Time for acon – Wring the pie chart script 217

Time for acon – Prefabulous 269
Time for acon – Lights, camera, apartment 272
Time for acon – Adding the character 273
Time for acon – Registering the animaons 274
Time for acon – Scripng the character 275
Time for acon – Opening the pod bay door, Hal 278
Time for acon – Collision-enable the character 278
Time for acon – Re-prefab the prefab 279
Time for acon – Apocalypse now? 280
Time for acon – Go boom 281
Time for acon – The point of impact 284
Time for acon – Hook up the explosion 285
Summary 286
Chapter 10: Game #3: The Break-Up Part 2 287
Time for acon – Amass some glass 287
Time for acon – Creang a Parcle System 288
Time for acon – Making it edgier! 291
Time for acon – Containing the explosion 292
Time for acon – Let's get lazy 293
Very variable? 296
Terminal velocity is a myth—bombs fall faster 296
Time for acon – Tagging the objects 297
Time for acon – Wring the collision detecon code 299
Time for acon – Animaon interrupts 300
Time for acon – Adding facial explosions 301
Time for acon – Making some noise 302
Time for acon – Adding sounds to the FallingObjectScript 303
What's the catch? 305
Time for acon – Mixing it up a bit 306
Summary 310

Time for acon – Animang the runner 367
Time for acon – How to "handle" Nurse Slipperfoot 369
Time for acon – You spin me right round 370
Time for acon – Deploying your game 373
Time to grow 375
Beyond the book 376
Table of Contents
[ ix ]
Appendix: References 377
Online resources 377
Oine resources 378
Free development tools 379
Graphics 379
Sound 379
Content sites 380
Game portals 380
Index 381

Preface
Beginner game developers are wonderfully opmisc, passionate, and ambious. But that
ambion is oen dangerous! Too oen, budding indie developers and hobbyists bite o
more than they can chew. Some of the most popular games in recent memory—Doodle
Jump, Angry Birds, and Canabalt, to name a few—have been fun, simple games that have
delighted players and delivered big prots to their creators. This is the perfect climate for
new game developers to succeed by creang simple games with Unity.
This book starts you o on the right foot, emphasizing small, simple game ideas and playable
projects that you can actually nish. The complexity of the games increases gradually as we
progress through the chapters. The chosen examples help you learn a wide variety of game
development techniques. With this understanding of Unity and bite-sized bits of programming,
you can make your own mark in the game industry by nishing fun, simple games.

Chapter 4, Code Comfort, connues the keep-up game project by gently introducing
scripng. Just by wring a few simple, thoroughly-explained lines of code, you can make
the paddle follow the mouse around the screen to add some interacvity to the game.
This chapter includes a crash course in game scripng that will renew your excitement for
programming where high school computer classes may have failed you.
Chapter 5, Game#2: Robot Repair, introduces an oen-overlooked aspect of game
development: "front-of-house" user interface design—the buons, logos, screens, dials,
bars, and sliders that sit in front of your game—is a complete discipline unto itself. Unity
3D includes a very meaty Graphical User Interface system that allows you to create controls
and ddly bits to usher your players through your game. We'll explore this system, and start
building a complete two-dimensional game with it! By the end of this chapter, you'll be
halfway to compleng Robot Repair, a colorful matching game with a twist.
Chapter 6, Game#2: Robot Repair Part 2, picks up where the last chapter le o. We'll add
interacvity to our GUI-based game, and add important tools to our game development tool
belt, including drawing random numbers and liming player control. When you're nished
with this chapter, you'll have a completely playable game using only the Unity GUI system,
and you'll have enough inial knowledge to explore the system yourself to create new
control schemes for your games.
Preface
[ 3 ]
Chapter 7, Don't be a Clock Blocker, is a standalone chapter that shows you how to build
three dierent game clocks: a number-based clock, a depleng bar clock, and a cool pie
wedge clock, all of which use the same underlying code. You can then add one of these
clocks to any of the game projects in this book, or reuse the code in a game of your own.
Chapter 8, Ticker Taker, revisits the keep-up game from earlier chapters and replaces the
simple primives with 3D models. You'll learn how to create materials and apply them to
models that you import from external art packages. You'll also learn how to detect collisions
between Game Objects, and how to print score results to the screen. By the end of this
chapter, you'll be well on your way to building Ticker Taker—a game where you bounce a
sll-beang human heart on a hospital dinner tray in a mad dash for the transplant ward!

Unity 3D (
A list of resources and links to
addional soware can be found in the appendix.
Who this book is for
If you've ever wanted to develop games, but have never felt "smart" enough to deal with
complex programming, this book is for you. It's also a great kick-start for developers coming
from other tools like Flash, Unreal Engine, and Game Maker Pro.
Conventions
In this book, you will nd several headings appearing frequently.
To give clear instrucons of how to complete a procedure or task, we use:
Time for action – heading
1. Acon 1
2. Acon 2
3. Acon 3
Instrucons oen need some extra explanaon so that they make sense, so they are
followed with:
What just happened?
This heading explains the working of tasks or instrucons that you have just completed.
You will also nd some other learning aids in the book, including:
Pop quiz – heading
These are short mulple choice quesons intended to help you test your own understanding.
Preface
[ 5 ]
Have a go hero – heading
These set praccal challenges and give you ideas for experimenng with what you have
learned.
You will also nd a number of styles of text that disnguish between dierent kinds of
informaon. Here are some examples of these styles, and an explanaon of their meaning.
Code words in text are shown as follows: "The result is that the rst me the
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Preface
[ 7 ]
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