.OpenGL®Programming GuideSeventh Edition.OpenGL Series®Visit informit.com /opengl for a ppt

OpenGL®

Programming Guide

Seventh Edition

The OpenGL graphics system is a software interface to graphics

hardware. (“GL” stands for “Graphics Library.”) It allows you to

create interactive programs that produce color images of moving, three￾dimensional objects. With OpenGL, you can control computer-graphics

technology to produce realistic pictures, or ones that depart from reality

in imaginative ways.

The OpenGL Series from Addison-Wesley Professional comprises

tutorial and reference books that help programmers gain a practical

understanding of OpenGL standards, along with the insight needed to

unlock OpenGL’s full potential.

Visit informit.com/opengl for a complete list of available products

OpenGL®

Series

OpenGL®

Programming Guide

Seventh Edition

The Official Guide to

Learning OpenGL®

, Versions 3.0 and 3.1

Dave Shreiner

The Khronos OpenGL ARB Working Group

Upper Saddle River, NJ • Boston • Indianapolis • San Francisco

New York • Toronto • Montreal • London • Munich • Paris • Madrid

Capetown • Sydney • Tokyo • Singapore • Mexico City

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 publisher was

aware of a trademark claim, the designations have been printed with initial capital letters or

in all capitals.

The authors and publisher have taken care in the preparation of this book, but make no

expressed or implied warranty of any kind and assume no responsibility for errors or

omissions. No liability is assumed for incidental or consequential damages in connection

with or arising out of the use of the information or programs contained herein.

The publisher offers excellent discounts on this book when ordered in quantity for bulk

purchases or special sales, which may include electronic versions and/or custom covers and

content particular to your business, training goals, marketing focus, and branding interests.

For more information, please contact:

U.S. Corporate and Government Sales

(800) 382-3419

[email protected]

For sales outside of the U.S., please contact:

International Sales

[email protected]

Visit us on the Web: informit.com/aw

Library of Congress Cataloging-in-Publication Data

Shreiner, Dave.

OpenGL programming guide : the official guide to learning OpenGL, versions 3.0 and 3.1

/ Dave Shreiner; the Khronos OpenGL ARB Working Group — 7th ed.

p. cm.

Includes index.

ISBN 978-0-321-55262-4 (pbk. : alk. paper)

1. Computer graphics. 2. OpenGL. I. Title.

T385.O635 2009

006.6'6—dc22

2009018793

Copyright © 2010 Pearson Education, Inc.

All rights reserved. Printed in the United States of America. This publication is protected by

copyright, and permission must be obtained from the publisher prior to any prohibited

reproduction, storage in a retrieval system, or transmission in any form or by any means,

electronic, mechanical, photocopying, recording, or likewise. For information regarding

permissions, write to:

Pearson Education, Inc.

Rights and Contracts Department

501 Boylston Street, Suite 900

Boston, MA 02116

Fax (617) 671-3447

ISBN 13: 978-0-321-55262-4

ISBN 10: 0-321-55262-8

Text printed in the United States on recycled paper at Edwards Brothers in Ann Arbor, Michigan.

First printing, July 2009

For my family—Felicity, Max, Sarah, and Scout.

—JLN

For my family—Ellyn, Ricky, and Lucy.

—TRD

To Tom Doeppner and Andy van Dam, who started me along this path.

—MW

For my family—Vicki, Bonnie, Bob, Phantom, Squiggles, Tuxedo, and Toby.

—DRS

In memory of Phil Karlton, Celeste Fowler, and Ben Cheatham.

This page intentionally left blank

vii

Contents

Figures ................................................................................................xxi

Tables ................................................................................................xxv

Examples ..........................................................................................xxix

About This Guide .............................................................................xxxv

What This Guide Contains...............................................................xxxv

What’s New in This Edition ..........................................................xxxviii

What You Should Know Before Reading This Guide............................xl

How to Obtain the Sample Code .........................................................xli

Errata....................................................................................................xlii

Style Conventions ...............................................................................xlii

Distinguishing Deprecated Features...................................................xliii

Acknowledgments .................................................................................xlv

1. Introduction to OpenGL............................................................................1

What Is OpenGL? ...................................................................................2

A Smidgen of OpenGL Code ..................................................................5

OpenGL Command Syntax....................................................................7

OpenGL as a State Machine ...................................................................9

OpenGL Rendering Pipeline.................................................................10

Display Lists....................................................................................11

Evaluators .......................................................................................11

Per-Vertex Operations ....................................................................12

Primitive Assembly.........................................................................12

viii Contents

Pixel Operations............................................................................. 13

Texture Assembly........................................................................... 13

Rasterization................................................................................... 14

Fragment Operations ..................................................................... 14

OpenGL-Related Libraries .................................................................... 14

Include Files ................................................................................... 15

GLUT, the OpenGL Utility Toolkit................................................ 17

Animation ............................................................................................ 22

The Refresh That Pauses................................................................. 23

Motion = Redraw + Swap ............................................................... 24

OpenGL and Its Deprecation Mechanism ........................................... 27

OpenGL Contexts .......................................................................... 27

Accessing OpenGL Functions ........................................................ 29

2. State Management and Drawing Geometric Objects .......................... 31

A Drawing Survival Kit......................................................................... 34

Clearing the Window .................................................................... 34

Specifying a Color.......................................................................... 37

Forcing Completion of Drawing.................................................... 38

Coordinate System Survival Kit ..................................................... 40

Describing Points, Lines, and Polygons............................................... 42

What Are Points, Lines, and Polygons?......................................... 42

Specifying Vertices......................................................................... 46

OpenGL Geometric Drawing Primitives........................................ 47

Basic State Management ...................................................................... 53

Displaying Points, Lines, and Polygons............................................... 55

Point Details................................................................................... 55

Line Details .................................................................................... 56

Polygon Details .............................................................................. 60

Normal Vectors .................................................................................... 68

Vertex Arrays ........................................................................................ 70

Step 1: Enabling Arrays .................................................................. 72

Step 2: Specifying Data for the Arrays ........................................... 73

Step 3: Dereferencing and Rendering ............................................ 77

Restarting Primitives...................................................................... 83

Instanced Drawing......................................................................... 86

Interleaved Arrays .......................................................................... 88

Contents ix

Buffer Objects .......................................................................................91

Creating Buffer Objects ..................................................................92

Making a Buffer Object Active .......................................................93

Allocating and Initializing Buffer Objects with Data.....................93

Updating Data Values in Buffer Objects ........................................96

Copying Data Between Buffer Objects.........................................101

Cleaning Up Buffer Objects..........................................................102

Using Buffer Objects with Vertex-Array Data ..............................102

Vertex-Array Objects...........................................................................104

Attribute Groups.................................................................................110

Some Hints for Building Polygonal Models of Surfaces.....................113

An Example: Building an Icosahedron ........................................115

3. Viewing.................................................................................................. 123

Overview: The Camera Analogy.........................................................126

A Simple Example: Drawing a Cube ............................................129

General-Purpose Transformation Commands .............................134

Viewing and Modeling Transformations ...........................................137

Thinking about Transformations.................................................137

Modeling Transformations...........................................................140

Viewing Transformations.............................................................146

Projection Transformations................................................................152

Perspective Projection ..................................................................153

Orthographic Projection ..............................................................156

Viewing Volume Clipping............................................................158

Viewport Transformation...................................................................158

Defining the Viewport .................................................................159

The Transformed Depth Coordinate............................................161

Troubleshooting Transformations......................................................162

Manipulating the Matrix Stacks .........................................................164

The Modelview Matrix Stack........................................................167

The Projection Matrix Stack.........................................................168

Additional Clipping Planes.................................................................168

Examples of Composing Several Transformations.............................172

Building a Solar System ................................................................172

Building an Articulated Robot Arm..............................................175

Reversing or Mimicking Transformations..........................................179

x Contents

4. Color ...................................................................................................... 185

Color Perception ................................................................................ 186

Computer Color ................................................................................. 188

RGBA versus Color-Index Mode ........................................................ 190

RGBA Display Mode..................................................................... 191

Color-Index Display Mode........................................................... 193

Choosing between RGBA and Color-Index Mode....................... 195

Changing between Display Modes .............................................. 196

Specifying a Color and a Shading Model........................................... 196

Specifying a Color in RGBA Mode............................................... 197

Specifying a Color in Color-Index Mode..................................... 199

Specifying a Shading Model......................................................... 200

5. Lighting ................................................................................................. 203

A Hidden-Surface Removal Survival Kit............................................. 205

Real-World and OpenGL Lighting..................................................... 207

Ambient, Diffuse, Specular, and Emissive Light.......................... 208

Material Colors............................................................................. 209

RGB Values for Lights and Materials ........................................... 209

A Simple Example: Rendering a Lit Sphere........................................ 210

Creating Light Sources ....................................................................... 214

Color ............................................................................................ 216

Position and Attenuation ............................................................ 217

Spotlights ..................................................................................... 219

Multiple Lights............................................................................. 220

Controlling a Light’s Position and Direction .............................. 221

Selecting a Lighting Model ................................................................ 227

Global Ambient Light .................................................................. 228

Local or Infinite Viewpoint ......................................................... 229

Two-Sided Lighting...................................................................... 229

Secondary Specular Color ............................................................ 230

Enabling Lighting ........................................................................ 231

Defining Material Properties .............................................................. 231

Diffuse and Ambient Reflection .................................................. 233

Specular Reflection....................................................................... 234

Emission....................................................................................... 234

Contents xi

Changing Material Properties ......................................................235

Color Material Mode ....................................................................237

The Mathematics of Lighting .............................................................240

Material Emission.........................................................................241

Scaled Global Ambient Light .......................................................242

Contributions from Light Sources ...............................................242

Putting It All Together..................................................................244

Secondary Specular Color.............................................................245

Lighting in Color-Index Mode ...........................................................246

The Mathematics of Color-Index Mode Lighting........................247

6. Blending, Antialiasing, Fog, and Polygon Offset.............................. 249

Blending..............................................................................................251

The Source and Destination Factors.............................................252

Enabling Blending........................................................................255

Combining Pixels Using Blending Equations..............................255

Sample Uses of Blending ..............................................................258

A Blending Example .....................................................................260

Three-Dimensional Blending with the Depth Buffer...................263

Antialiasing.........................................................................................267

Antialiasing Points or Lines..........................................................269

Antialiasing Geometric Primitives with Multisampling ..............275

Antialiasing Polygons...................................................................279

Fog.......................................................................................................280

Using Fog......................................................................................281

Fog Equations ...............................................................................284

Point Parameters.................................................................................291

Polygon Offset ....................................................................................293

7. Display Lists ......................................................................................... 297

Why Use Display Lists?.......................................................................298

An Example of Using a Display List ...................................................299

Display List Design Philosophy..........................................................302

Creating and Executing a Display List ...............................................305

Naming and Creating a Display List ............................................306

What’s Stored in a Display List?...................................................307

xii Contents

Executing a Display List............................................................... 309

Hierarchical Display Lists............................................................. 310

Managing Display List Indices..................................................... 311

Executing Multiple Display Lists........................................................ 312

Managing State Variables with Display Lists ..................................... 318

Encapsulating Mode Changes...................................................... 319

8. Drawing Pixels, Bitmaps, Fonts, and Images .................................... 321

Bitmaps and Fonts.............................................................................. 323

The Current Raster Position......................................................... 325

Drawing the Bitmap..................................................................... 327

Choosing a Color for the Bitmap ................................................ 328

Fonts and Display Lists ................................................................ 329

Defining and Using a Complete Font.......................................... 331

Images ................................................................................................ 333

Reading, Writing, and Copying Pixel Data ................................. 333

Imaging Pipeline ................................................................................ 343

Pixel Packing and Unpacking ...................................................... 346

Controlling Pixel-Storage Modes................................................. 347

Pixel-Transfer Operations ............................................................ 351

Pixel Mapping .............................................................................. 354

Magnifying, Reducing, or Flipping an Image.............................. 356

Reading and Drawing Pixel Rectangles.............................................. 359

The Pixel Rectangle Drawing Process .......................................... 359

Using Buffer Objects with Pixel Rectangle Data ................................ 362

Using Buffer Objects to Transfer Pixel Data ................................ 363

Using Buffer Objects to Retrieve Pixel Data ................................ 365

Tips for Improving Pixel Drawing Rates ............................................ 366

Imaging Subset ................................................................................... 367

Color Tables ................................................................................. 369

Convolutions ............................................................................... 374

Color Matrix................................................................................. 382

Histogram..................................................................................... 383

Minmax........................................................................................ 387

Contents xiii

9. Texture Mapping................................................................................... 389

An Overview and an Example............................................................395

Steps in Texture Mapping ............................................................395

A Sample Program ........................................................................397

Specifying the Texture........................................................................400

Texture Proxy ...............................................................................406

Replacing All or Part of a Texture Image......................................408

One-Dimensional Textures ..........................................................412

Three-Dimensional Textures ........................................................414

Texture Arrays ..............................................................................419

Compressed Texture Images.........................................................420

Using a Texture’s Borders.............................................................423

Mipmaps: Multiple Levels of Detail .............................................423

Filtering...............................................................................................434

Texture Objects...................................................................................437

Naming a Texture Object .............................................................438

Creating and Using Texture Objects ............................................438

Cleaning Up Texture Objects .......................................................441

A Working Set of Resident Textures.............................................442

Texture Functions...............................................................................444

Assigning Texture Coordinates ..........................................................448

Computing Appropriate Texture Coordinates.............................450

Repeating and Clamping Textures...............................................452

Automatic Texture-Coordinate Generation .......................................457

Creating Contours........................................................................458

Sphere Map...................................................................................463

Cube Map Textures.......................................................................465

Multitexturing ....................................................................................467

Texture Combiner Functions .............................................................472

The Interpolation Combiner Function ........................................477

Applying Secondary Color after Texturing ........................................478

Secondary Color When Lighting Is Disabled...............................478

Secondary Specular Color When Lighting Is Enabled .................479

Point Sprites........................................................................................479

The Texture Matrix Stack....................................................................481

xiv Contents

Depth Textures................................................................................... 483

Creating a Shadow Map............................................................... 483

Generating Texture Coordinates and Rendering ........................ 485

10. The Framebuffer ................................................................................... 489

Buffers and Their Uses........................................................................ 492

Color Buffers ................................................................................ 493

Clearing Buffers............................................................................ 495

Selecting Color Buffers for Writing and Reading ........................ 497

Masking Buffers............................................................................ 499

Testing and Operating on Fragments ................................................ 501

Scissor Test ................................................................................... 502

Alpha Test .................................................................................... 502

Stencil Test ................................................................................... 504

Depth Test.................................................................................... 510

Occlusion Query .......................................................................... 511

Conditional Rendering ................................................................ 514

Blending, Dithering, and Logical Operations.............................. 515

The Accumulation Buffer ................................................................... 518

Motion Blur.................................................................................. 520

Depth of Field .............................................................................. 520

Soft Shadows ................................................................................ 525

Jittering ........................................................................................ 525

Framebuffer Objects ........................................................................... 526

Renderbuffers ............................................................................... 529

Copying Pixel Rectangles............................................................. 539

11. Tessellators and Quadrics................................................................... 541

Polygon Tessellation .......................................................................... 542

Creating a Tessellation Object ..................................................... 544

Tessellation Callback Routines .................................................... 544

Tessellation Properties ................................................................. 549

Polygon Definition ...................................................................... 554

Deleting a Tessellation Object ..................................................... 557

Tessellation Performance Tips ..................................................... 557

Describing GLU Errors ................................................................. 557

Backward Compatibility .............................................................. 558