Table Of ContentREAL-WORLD FLASH GAME
DEVELOPMENT
HOW TO FOLLOW BEST PRACTICES AND
KEEP YOUR SANITY
CHRIS GRIFFITH
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Library of Congress Cataloging-in-Publication Data
Griffi th , Christopher, 1979-
R eal-world Flash game development : how to follow best practices
and keep your sanity/
Christopher Griffi th.
p. cm.
Includes index.
ISBN 978-0-240-81178-9 (pbk.: alk. paper) 1. Computer games –
Programming. 2. Computer animation. 3. Flash (Computer fi le) I. Title.
QA76.76.C672G774 2009
794.8’1526 – dc22
2009020027
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.
ISBN : 978-0-240-81178-9
For information on all Focal Press publications
visit our website at www.books.elsevier.com
09 10 11 5 4 3 2 1
Printed in Canada.
.
CONTENTS
Acknowledgments ................................................................................................. x
Introduction ............................................................................................................ xi
Chapter 1 Computer Science Isn’t for Everyone ............................................... 1
A Little Groundwork .....................................................................................1
Common Game Types ..................................................................................1
General Development Terms .......................................................................5
Game-Specifi c Development Terms ............................................................8
Flash Development Terms ..........................................................................10
You Can Wake Back Up Now .....................................................................12
Chapter 2 The Best Tool for the Job .................................................................. 13
Flash Back ...................................................................................................13
The Case For Flash .....................................................................................14
Nobody’s Perfect.........................................................................................15
Stop Fighting It ...........................................................................................20
Things Flash Was Built to Do .....................................................................21
The Best Tool for the Job ...........................................................................23
Chapter 3 A Plan is Worth a Thousand Aspirin ............................................... 25
Step 1. Be Able to Describe the Game from a Bird’s-Eye View in
One or Two Sentences ................................................................................25
Step 2. Outline or Wireframe Out the Flow of All of the Game’s
Screens ........................................................................................................26
Step 3. With Your Description and Basic Wireframe in Hand, It’s Time
to Outline the Core Mechanics That Your Game Will Utilize ....................27
Step 4. Build an Asset List .........................................................................28
Step 5. Make a List of Technical Requirements for Your Game ...............30
Step 6 (Optional). Diagram Your Classes Using a UML Modeler ...........32
A Quick Review of the Planning Steps......................................................33
iii
iv CONTENTS
Chapter 4 //FTW! ................................................................................................... 35
Fair Warning ................................................................................................35
PART 1: Classes .......................................................................................... 3 5
Packages ......................................................................................................36
Classes as Files ...........................................................................................36
Constructors ...............................................................................................37
Constants, Variables, and Methods ...........................................................37
Getter/Setter Methods ................................................................................39
Class Identifi ers ..........................................................................................40
Inheritance and Polymorphism .................................................................41
Interfaces .....................................................................................................42
Linking Classes to Assets in Flash ............................................................45
Class vs. Base Class ...................................................................................46
Using Exported Symbols with No Class File ............................................48
getDefi nitionByName and Casting ...........................................................48
PART 2: Events ............................................................................................ 4 9
dispatchEvent .............................................................................................49
addEventListener, removeEventListener, and Event Phases ..................50
Event Propagation and Cancellation .........................................................53
Custom Events ............................................................................................54
PART 3: Errors ............................................................................................. 5 5
try, catch, fi nally ..........................................................................................56
Throwing Your Own Errors ........................................................................57
PART 4: Data Structures and Lists ............................................................. 5 8
Objects ........................................................................................................59
Arrays ..........................................................................................................60
Vectors .........................................................................................................62
Dictionaries .................................................................................................62
ByteArrays ...................................................................................................63
So What Should I Use For My Lists? .........................................................63
Custom Data Structures .............................................................................64
CONTENTS v
PART 5: Keep Your Comments to Everyone Else! .................................... 6 4
The Bottom Line .........................................................................................65
PART 6: Why Does Flash Do That? ............................................................. 6 5
Event Flow ..................................................................................................66
Frame Scripts ..............................................................................................66
Working with Multiple SWF Files ..............................................................69
Garbage Collection .....................................................................................71
Conclusion ..................................................................................................73
Chapter 5 Managing Your Assets/Working With Graphics .......................... 75
A Few Words About Organization .............................................................76
Working with Graphics ..............................................................................77
Raster Formats to Use ................................................................................78
Key Points to Remember ...........................................................................84
Chapter 6 Make It Move: ActionScript Animation ......................................... 85
A Little Terminology ....................................................................................86
To Tween or Not to Tween? Is That a Question?........................................86
A Simple Scripted Shooter ........................................................................87
Memory: Tweening Animation ..................................................................90
Summary ....................................................................................................95
Chapter 7 Turn It Up to 11: Working With Audio ............................................. 97
Formats to Use ...........................................................................................97
Export Settings to Use ...............................................................................98
Using External Files .................................................................................101
Tools for Working with Sounds ................................................................101
Scripting Sounds .......................................................................................101
Chapter 8 Put the Video Back in “ Video Game ” ........................................... 115
Video Codecs .............................................................................................115
External Video Uses: Cutscenes and Menus ...........................................116
vi CONTENTS
The CutsceneManager ..............................................................................119
Video on the Timeline................................................................................123
Setting Up an Internal Video .....................................................................125
Summary ...................................................................................................128
Chapter 9 XML and Dynamic Content ............................................................. 129
Bringing Data In: Understanding the URLLoader Class .........................129
XML ............................................................................................................130
E4X .............................................................................................................130
The Crossword Puzzle ...............................................................................131
Content Is a Two-Way Street: A Crossword Builder ................................148
Sending Data Back Out .............................................................................149
One More Example: XML vs. Flash Vars ..................................................149
Summary ...................................................................................................151
Chapter 10 Four Letter Words: M-A-T-H ......................................................... 153
The Math Class ..........................................................................................153
PART 1: Geometry and Trigonometry......................................................153
A Quick Explanation of Radians and Pi....................................................158
3D in Flash .................................................................................................161
The SimpleTunnelShooter Example ........................................................164
PART 2: Physics .........................................................................................175
Scalar ..........................................................................................................175
Vector..........................................................................................................175
The Vector3D Class ....................................................................................175
Displacement .............................................................................................176
Velocity .......................................................................................................176
Acceleration ...............................................................................................176
Friction........................................................................................................177
Inertia..........................................................................................................177
Simulation vs. Illusion ..............................................................................177
Reality vs. Expectations ............................................................................178
CONTENTS vii
Example: A Top-Down Driving Engine .....................................................178
Example: Top-Down Driving Game with Drift .........................................184
Review ........................................................................................................186
Chapter 11 Don’t Hit Me! ................................................................................... 189
What You Can Do vs. What You Need .......................................................189
hitTestObject—The Most Basic Detection ...............................................189
hitTestPoint—One Step Up .......................................................................190
Radius/Distance Testing—Great for Circles .............................................194
Rect Testing ................................................................................................195
When All Else Fails, Mix ‘n’ Match ...........................................................200
Chapter 12 I Always Wanted to Be An Architect .......................................... 201
OOP Concepts ............................................................................................201
Practical OOP in Game Development ......................................................204
The Singleton: A Good Document Pattern ..............................................206
Summary ...................................................................................................208
Chapter 13 We’ve All Been There .................................................................... 209
Basic Encapsulation—Classes and Containers ........................................210
Store Relevant Values in Variables and Constants ..................................210
Don’t Rely on Your Stage ..........................................................................212
Don’t Use Frameworks or Patterns That You
Don’t Understand or That Don’t Apply ....................................................212
Know When It’s Okay to Phone It in and When It Definitely Isn’t ..........213
Conclusion .................................................................................................213
Chapter 14 MixUp — A Simple Engine ............................................................ 215
The Main Document ..................................................................................217
The MixUp Class .......................................................................................217
The Title Class ............................................................................................220
The RulesPanel Class ................................................................................220
The Game Class .........................................................................................221
viii CONTENTS
The Interfaces ............................................................................................224
The GameBoard Class ..............................................................................226
The SourceImageEmbedded Class ..........................................................233
The GameHistory and Results Classes ....................................................234
The SourceImageCamera Class ...............................................................236
Review ........................................................................................................238
Chapter 15 Bringing It All Together: A Platformer ........................................ 239
The Platformer Genre ...............................................................................239
Data Flow ...................................................................................................240
The Game Flow and Features ...................................................................241
The Level File Format and Asset Structure .............................................244
The Engine Classes ...................................................................................248
The Game Class .........................................................................................271
The Asset Classes ......................................................................................273
Taking It Further .........................................................................................279
Chapter 16 Don’t Play By Yourself: Multiplayer Development ................... 281
RTMFP ........................................................................................................281
Stratus ........................................................................................................282
MixUp Multiplayer ....................................................................................282
Conclusion .................................................................................................292
Chapter 17 Squash ‘ Em If You’ve Got ‘ Em: The Bug Hunt ............................ 293
Bugs ............................................................................................................293
Performance/Optimization ........................................................................298
Summary ...................................................................................................306
Chapter 18 On Your Guard ................................................................................. 307
Malicious Use ............................................................................................307
Data Protection ..........................................................................................309
SWF Protection ..........................................................................................314
Summary ...................................................................................................315
CONTENTS ix
AFTERWORD ........................................................................................................ 317
APPENDIX A Webcams and Microphones .................................................... A-1
INDEX ..................................................................................................................... I-1
ONLINE CONTENTS
APPENDIX B Localization ................................................................................. B-1
APPENDIX C JSFL is JavaScript For Lovers .................................................. C-1
