Beginning OpenGL Game Programming, Second Edition

319 Pages·2009·2.86 MB·English

by  Luke (Luke Benstead) Benstead

Beginning
(cid:2)
OpenGL
R
Game
Programming,
Second Edition
Luke Benstead
with
Dave Astle and Kevin Hawkins
Course Technology PTR
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For Alison.
Acknowledgments
First,I’dliketothankmygirlfriendAlison,whosupportedmewhileIwaswriting
this book and provided me with endless cups of tea throughout. I promise I’ll
spend less time on the computer now. . . for a little while anyway.
I would also like to thank Carsten Haubold for being an excellent technical
editor,andespeciallyforhishelpwiththesampleapplications;withouthim,they
wouldnotlook asgood,beasstable, orbesonumerous. It’sbeengreatworking
with you, Carsten. Thanks also to Jenny, Heather, and Brandon, and everyone
who has been involved in producing this book; you’re all great!
Jeff Molofee deserves a special mention. If he didn’t start the NeHe website I
would never have become interested in OpenGL and programming in general.
I’d like to thank my family: Gayna and Nigel, Stephen and Terry, Josh, Lee,
Abigail, and George and the many others I don’t have room to mention! And
lastly, I’d like to thank my friends: Sean, Jayne, Rob, Hayley, and Natalie and
Wayne. Thanks for the much deserved distractions.
About the Authors
Luke Benstead is a co-maintainer of http://nehe.gamedev.net/ and has been
programming in OpenGL and C++ for 7 years. He is currently a software
developer in London, England. He has a bachelor’s degree in Multimedia Pro-
gramming from the University of Portsmouth.
Kevin Hawkins received a bachelor’s degree in Computer Science and master’s
degreeinSoftwareEngineeringfromEmbry-RiddleUniversity.Heiscurrentlythe
Technical Director of Software Engineering at Raydon Corporation. Along with
Dave, Kevin is co-founder of GameDev.net and co-author of the first edition of
Beginning OpenGL Game Programming and More OpenGL Game Programming.
Dave Astle has been involved in the world of game development for over a
decade.Currently,he’sastaffengineerandtechnologyevangelistintheAdvanced
Content Group at QUALCOMM, Inc. He cofounded GameDev.net, where he
currently servesasCEO and ExecutiveDirector. Heco-authored the firstedition
of Beginning OpenGL Game Programming, OpenGL Game Programming, More
OpenGLGameProgramming,andOpenGLESGameDevelopment,contributedto
several other game development books, and speaks regularly at industry con-
ferences, including the Game Developers Conference. He has a bachelor’s degree
in Computer Science from the University of Utah.
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Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
PART 1 OPENGL BASICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 1 The Exploration Begins . . . Again . . . . . . . . . . . . . . . . . . 3
Why Make Games?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The World of 3D Games. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
The Elements of a Game . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
What Is OpenGL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
OpenGL History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
OpenGL Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Fixed-Function vs. Programmability . . . . . . . . . . . . . . . . . . . . . . 8
The Deprecation Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Deprecated Features in This Book . . . . . . . . . . . . . . . . . . . . . . 10
Related Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
A Sneak Peek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
What You Have Learned. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
On Your Own. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
vii
viii Contents
Chapter 2 Creating a Simple OpenGL Application . . . . . . . . . . . . . . 17
About the Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Introduction to WGL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
The Rendering Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Pixel Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
nSize. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
dwFlags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
iPixelType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
cColorBits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Setting the Pixel Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
An OpenGL Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Full-Screen OpenGL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
The Example Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
What You Have Learned. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
On Your Own. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Chapter 3 OpenGL States and Primitives . . . . . . . . . . . . . . . . . . . . 43
State Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Querying Numeric States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Enabling and Disabling States. . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
glIsEnabled() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Querying String Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
glGetStringi(). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Finding Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Colors in OpenGL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Handling Primitives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Immediate Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Vertex Arrays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Vertex Buffer Objects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Drawing Points in 3D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Drawing Lines in 3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Drawing Triangles in 3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
What You Have Learned. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
On Your Own. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Contents ix
Chapter 4 Transformations and Matrices . . . . . . . . . . . . . . . . . . . . 73
Understanding Coordinate Transformations. . . . . . . . . . . . . . . . . . 73
Eye Coordinates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Viewing Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Modeling Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Projection Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Viewport Transformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Fixed-Function OpenGL and Matrices . . . . . . . . . . . . . . . . . . . . . . 80
The Modelview Matrix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Scaling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Matrix Stacks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
The Robot Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Orthographic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Setting the Viewport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Projection Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Manipulating the Viewpoint. . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Using gluLookAt() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Using glRotate() and glTranslate() . . . . . . . . . . . . . . . . . . . . . 103
Creating Your Own Custom Routines . . . . . . . . . . . . . . . . . . . 104
Using Your Own Matrices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Loading Your Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Multiplying Matrices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
What You Have Learned. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
On Your Own. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Chapter 5 OpenGL Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
What Is an Extension? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Extension Naming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Name Strings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Functions and Tokens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Obtaining a Function’s Entry Point . . . . . . . . . . . . . . . . . . . . . . . 114
Extensions on Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Finding Supported Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
WGL Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118