OpenGL^® Programming Guide, Sixth Edition

OpenGL is a powerful software interface used to produce high-quality, computergenerated images and interactive applications using 2D and 3D objects, bitmaps, and color images.

The OpenGL^® Programming Guide, Sixth Edition, provides definitive and comprehensive information on OpenGL and the OpenGL Utility Library. The previous edition covered OpenGL through Version 2.0. This sixth edition of the best-selling "red book" describes the latest features of OpenGL Version 2.1. You will find clear explanations of OpenGL functionality and many basic computer graphics techniques, such as building and rendering 3D models; interactively viewing objects from different perspective points; and using shading, lighting, and texturing effects for greater realism. In addition, this book provides in-depth coverage of advanced techniques, including texture mapping, antialiasing, fog and atmospheric effects, NURBS, image processing, and more. The text also explores other key topics such as enhancing performance, OpenGL extensions, and cross-platform techniques.

This sixth edition has been updated to include the newest features of OpenGL Version 2.1, including:

• Using server-side pixel buffer objects for fast pixel rectangle download and retrieval
• Discussion of the sRGB texture format
• Expanded discussion of the OpenGL Shading Language

This edition continues the discussion of the OpenGL Shading Language (GLSL) and explains the mechanics of using this language to create complex graphics effects and boost the computational power of OpenGL.

The OpenGL Technical Library provides tutorial and reference books for OpenGL. The Library enables programmers to gain a practical understanding of OpenGL and shows them how to unlock its full potential. Originally developed by SGI, the Library continues to evolve under the auspices of the OpenGL Architecture Review Board (ARB) Steering Group (now part of the Khronos Group), an industry consortium responsible for guiding the evolution of OpenGL and related technologies.

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      xxxviii

How to Obtain the Sample Code      xxxix

Nate Robins' OpenGL Tutors       xl

Errata       xl

Style Conventions       xl

Acknowledgments       xliii

Chapter 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

OpenGL-Related Libraries       14

Animation 20

Chapter 2: State Management and Drawing Geometric Objects       27

A Drawing Survival Kit       29

Describing Points, Lines, and Polygons        37

Basic State Management       48

Displaying Points, Lines, and Polygons       50

Normal Vectors       63

Vertex Arrays       65

Buffer Objects       82

Attribute Groups       91

Some Hints for Building Polygonal Models of Surfaces       94

Chpater 3: Viewing       103

Overview: The Camera Analogy       106

Viewing and Modeling Transformations       117

Projection Transformations       133

Viewport Transformation       138

Troubleshooting Transformations       142

Manipulating the Matrix Stacks       145

Additional Clipping Planesv 149

Examples of Composing Several Transformations       152

Reversing or Mimicking Transformations       160

Chapter 4: Color       165

Color Perception       166

Computer Color       168

RGBA versus Color-Index Mode 170

Specifying a Color and a Shading Model       176

Chapter 5: Lighting 183

A Hidden-Surface Removal Survival Kit 185

Real-World and OpenGL Lighting 187

A Simple Example: Rendering a Lit Sphere 190

Creating Light Sources 194

Selecting a Lighting Model 207

Defining Material Properties 211

The Mathematics of Lighting 220

Lighting in Color-Index Mode 226

Chapter 6: Blending, Antialiasing, Fog, and Polygon Offset       229

Blending       231

Antialiasing       247

Fogv 261

Point Parameters       271

Polygon Offset v274

Chapter 7: Display Lists 277

Why Use Display Lists?       278

An Example of Using a Display List       279

Display List Design Philosophy v282

Creating and Executing a Display List       285

Executing Multiple Display v292

Managing State Variables with Display Lists        297

Chapter 8: Drawing Pixels, Bitmaps, Fonts, and Images       301

Bitmaps and Fonts       303

Images       312

Imaging Pipeline       321

Reading and Drawing Pixel Rectangles       337

Using Buffer Objects with Pixel Rectangle Data        341

Tips for Improving Pixel Drawing Rates       345

Imaging Subsetv 346

Chapter 9: Texture Mapping       369

An Overview and an Example       375

Specifying the Texture       380

Filtering       411

Texture Objects       414

Texture Functions       421

Assigning Texture Coordinates       425

Automatic Texture-Coordinate Generation       434

Multitexturing       443

Texture Combiner Functions       449

Applying Secondary Color after Texturing       455

Sprites       456

The Texture Matrix Stack       457

Depth Textures       459

Chapter 10: The Framebuffer       465

Buffers and Their Uses       468

Testing and Operating on Fragments       475

The Accumulation Bufferv 490

Chapter 11: Tessellators and Quadrics       505

Polygon Tessellation       506

Quadrics: Rendering Spheres, Cylinders, and Disks       523

Chapter 12: Evaluators and NURBS       533

Prerequisites       535

Evaluatorsv 536

The GLU NURBS Interface       550

Chapter 13: Selection and Feedback       569

Selection       570Feedbackv 591

Chapter 14: Now That You Knowv 599

Error Handling       601

Which Version Am I Using?       603

Extensions to the Standard       605

Cheesy Translucency       608

An Easy Fade Effect       608

Object Selection Using the Back Buffer       610

Cheap Image Transformation       611

Displaying Layers        612

Antialiased Characters       613

Drawing Round Points       616

Interpolating Images       616

Making Decals       616

Drawing Filled, Concave Polygons Using the Stencil Buffer       618

Finding Interference Regions       619

Shadows       621

Hidden-Line Removal       622

Texture Mapping Applications       624

Drawing Depth-Buffered Images       625

Dirichlet Domains       625

Life in the Stencil Buffer       627

Alternative Uses for glDrawPixels() and glCopyPixels()       628

Chapter 15: The OpenGL Shading Language       631

The OpenGL Graphics Pipeline and Programmable Shading       632

Using GLSL Shaders       636

The OpenGL Shading Language       644

Creating Shaders with GLSL       645

Accessing Texture Maps in Shaders       661

Shader Preprocessor       664

Appendix A: Order of Operations       679

Overview       680

Geometric Operations       681

Pixel Operations       682

Fragment Operations       683Odds and Ends       684

Appendix B: State Variables       685

The Query Commands       686

OpenGL State Variables       688

Appendix C: OpenGL and Window Systems       735

Accessing New OpenGL Functions       736

GLX: OpenGL Extension for the X Window System       737

AGL: OpenGL Extensions for the Apple Macintosh       744

PGL: OpenGL Extension for IBM OS/2 Warp       749

WGL: OpenGL Extension for Microsoft Windows 95/98/NT/ME/2000/XP      753

Appendix D: Basics of GLUT: The OpenGL Utility Toolkit       759

Initializing and Creating a Window       760

Handling Window and Input Events        761

Loading the Color Map       763

Initializing and Drawing Three-Dimensional Objects       763

Managing a Background Process       765

Running the Program      765

Appendix E: Calculating Normal Vectors       767

Finding Normals for Analytic Surfaces       769

Finding Normals from Polygonal Data       771

Homogeneous Coordinates       774

Transformation Matrices       775

Appendix G: Programming Tips       779

OpenGL Correctness Tips       780

OpenGL Performance Tips       782

GLX Tips 784

Appendix H: OpenGL Invariance       785

Appendix I: Built-In OpenGL Shading Language Variables and Functions       789

Variables       790

Built-In Functions       802

Glossary        815

Index       837