Game Programming All in One

833 Pages·11.278 MB·English

by  Jonathan S. Harbour

Game
Programming
All in One
Third Edition
Jonathan S. Harbour
(cid:2)2007 ThomsonCourse Technology, adivisionof ThomsonLearning Publisher and General Manager,
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Allegro, Audacity, and SourceForge are trademarks of VA Software
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For Jeremiah
Acknowledgments
Abookofthissizeinvolvesalotofworkevenafterthewritingisdone.Ittakesa
while just to read through a programming book once, so you can imagine how
difficultitistoreadthroughitseveraltimes,makingchangesandnotesalongthe
way,refining,correcting,preparingthebookforprint.Iamindebtedtothehard
work of the editors, artists, and layout specialists at Course Technology who do
such a fine job.
Many thanks go out to Jenny Davidson and Emi Smith.
IoweabigthankyoutoJoshuaSmithforhistechnicalexpertise.Hismanyyears
of experience in the game industry were invaluable for finding programming
errors and offering sound advice.
I believe you willfind this a true gem of a gameprogramming book dueto their
efforts.
About the Author
Jonathan S. Harbour is a senior instructor of game development at the Uni-
versity of Advancing Technology (www.uat.edu) in Tempe, Arizona, where he
teachesavarietyofgameprogrammingcourses.Whennotteachingothersabout
games, writing about games, or playing games, he enjoys audio/video editing,
wrenchingonoldFords(andgoingtolocalcarshows),andwatchingmovies.His
favoritegamedevelopmenttoolsareDarkBASIC,Allegro,andDirectX.Jonathan
is the author of three recent books: DarkBASIC Pro Game Programming, Second
Edition (with Joshua Smith), Beginning Java 5 Game Programming, and The
Gadget Geek’s Guide to Your Xbox 360.
Jonathanistheprojectleadofacontinuation gameintheclassicStarflightseries
(withthesupportofseriesfounderRodMcConnell).Thisgameisdueforrelease
in late 2007, and is being developed in C++ and Allegro as a 2D game (like the
originals).StarflightIwaspublishedbyElectronicArtsin1986,whilethesequel,
StarflightII:TradeRoutesoftheCloudNebula,cameoutin1989.Healsofounded
PrimevalGames,asmallstudiodedicatedtoproducinghumorouscasualgames,
and is working on a space shooter, intended for retail sale.
He lives in the Arizona desert with his wife, Jennifer, and four children:
Jeremiah, Kayleigh, Kaitlyn, and newcomer Kourtney. He can be reached at
www.jharbour.com.
Contents
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviii
PART I CROSS-PLATFORM GAME PROGRAMMING WITH THE
ALLEGRO GAME LIBRARY . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 1 Demystifying Game Development. . . . . . . . . . . . . . . . . . . .3
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Practical Game Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Goals Revisited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
The High-Level View of Game Development . . . . . . . . . . . . . . . . . . 7
Recognizing Your Personal Motivations. . . . . . . . . . . . . . . . . . . . . 10
Decision Point: College versus Job. . . . . . . . . . . . . . . . . . . . . . . 11
Every Situation Is Unique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
A Note about Specialization. . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Game Industry Speculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Emphasizing 2D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Finding Your Niche . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Getting into the Spirit of Gaming . . . . . . . . . . . . . . . . . . . . . . . . . 22
Starship Battles: An Inspired Fan Game. . . . . . . . . . . . . . . . . . . 22
Axis & Allies: Hobby Wargaming. . . . . . . . . . . . . . . . . . . . . . . . 30
Setting Realistic Expectations for Yourself. . . . . . . . . . . . . . . . . 33
vi
Contents vii
An Introduction to Allegro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
DirectX Is Just Another Game Library . . . . . . . . . . . . . . . . . . . . 34
Introducing the Allegro Game Library. . . . . . . . . . . . . . . . . . . . 36
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Chapter Quiz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Chapter 2 Getting Started with the Allegro Game Library. . . . . . . . . 43
Allegro’s Versatility Explained . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Configuring Your Favorite C++ Compiler. . . . . . . . . . . . . . . . . . . . 45
Overview of the Compiler Configurations. . . . . . . . . . . . . . . . . 46
Windows Platform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Linux Platform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Mac Platform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Taking Allegro for a Spin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Introducing Some of Allegro’s Features. . . . . . . . . . . . . . . . . . . 81
Running the GetInfo Program . . . . . . . . . . . . . . . . . . . . . . . . . 82
Adding to the GetInfo Program . . . . . . . . . . . . . . . . . . . . . . . . 82
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Chapter Quiz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Chapter 3 2D Vector Graphics Programming. . . . . . . . . . . . . . . . . . . 93
Your Ideal Game?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Graphics Fundamentals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
The InitGraphics Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
The DrawBitmap Program . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Drawing Graphics Primitives . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Drawing Pixels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Drawing Lines and Rectangles . . . . . . . . . . . . . . . . . . . . . . . . 109
Drawing Circles and Ellipses . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Drawing Splines, Triangles, and Polygons . . . . . . . . . . . . . . . . 128
Filling In Regions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Printing Text on the Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Constant Text Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Variable Text Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Testing Text Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Fun with Math and Vectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Chapter Quiz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
viii Contents
Chapter 4 Writing Your First Allegro Game. . . . . . . . . . . . . . . . . . . 149
Tank War . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Creating the Tanks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Firing Weapons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Tank Movement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Collision Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
The Complete Tank War Source Code. . . . . . . . . . . . . . . . . . . 157
Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Chapter Quiz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Chapter 5 Getting Input from the Player. . . . . . . . . . . . . . . . . . . . . 175
Handling Keyboard Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
The Keyboard Handler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
Detecting Key Presses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
The Stargate Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Buffered Keyboard Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Simulating Key Presses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
The KeyTest Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Handling Mouse Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
The Mouse Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Reading the Mouse Position. . . . . . . . . . . . . . . . . . . . . . . . . . 187
Detecting Mouse Buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Showing and Hiding the Mouse Pointer . . . . . . . . . . . . . . . . . 188
The Strategic Defense Game. . . . . . . . . . . . . . . . . . . . . . . . . . 190
Setting the Mouse Position. . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Limiting Mouse Movement and Speed . . . . . . . . . . . . . . . . . . 200
Relative Mouse Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Using a Mouse Wheel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Handling Joystick Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
The Joystick Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Detecting Controller Stick Movement . . . . . . . . . . . . . . . . . . . 205
Detecting Controller Buttons . . . . . . . . . . . . . . . . . . . . . . . . . 209
Testing the Joystick Routines . . . . . . . . . . . . . . . . . . . . . . . . . 210
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Chapter Quiz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Chapter 6 Mastering the Audible Realm. . . . . . . . . . . . . . . . . . . . . 221
The PlayWave Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Sound Initialization Routines. . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
Detecting the Digital Sound Driver. . . . . . . . . . . . . . . . . . . . . 225
Contents ix
Reserving Voices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Setting an Individual Voice Volume . . . . . . . . . . . . . . . . . . . . 225
Initializing the Sound Driver. . . . . . . . . . . . . . . . . . . . . . . . . . 226
Removing the Sound Driver . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Changing the Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Standard Sample Playback Routines. . . . . . . . . . . . . . . . . . . . . . . 227
Loading a Sample File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Playing and Stopping a Sample . . . . . . . . . . . . . . . . . . . . . . . 228
Altering a Sample’s Properties . . . . . . . . . . . . . . . . . . . . . . . . 228
Creating and Destroying Samples . . . . . . . . . . . . . . . . . . . . . . 228
Low-Level Sample Playback Routines. . . . . . . . . . . . . . . . . . . . . . 229
Allocating and Releasing Voices . . . . . . . . . . . . . . . . . . . . . . . 229
Starting and Stopping Playback . . . . . . . . . . . . . . . . . . . . . . . 229
Status and Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Controlling the Playback Position. . . . . . . . . . . . . . . . . . . . . . 230
Altering the Playback Mode. . . . . . . . . . . . . . . . . . . . . . . . . . 230
Volume Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Pitch Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Panning Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
The SampleMixer Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Playing Music . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Midi Basics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
Loading a Midi File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
Getting the Midi Length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Playing a Midi File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Example Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Chapter Quiz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
PART II SPRITE PROGRAMMING. . . . . . . . . . . . . . . . . . . . . . . . . 241
Chapter 7 Basic Bitmap Handling and Blitting. . . . . . . . . . . . . . . . . 243
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Dealing with Bitmaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
Creating Bitmaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
Cleaning House . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
Bitmap Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
Acquiring and Releasing Bitmaps . . . . . . . . . . . . . . . . . . . . . . 252
Bitmap Clipping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Loading Bitmaps from Disk. . . . . . . . . . . . . . . . . . . . . . . . . . . 253