Advanced graphics programming using openGL

Advanced Graphics

Programming

Using OpenGL

TOM McREYNOLDS

DAVID BLYTHE

AMSTERDAM • BOSTON • HEIDELBERG • LONDON

NEW YORK • OXFORD • PARIS • SAN DIEGO

SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO

MORGAN KAUFMANN PUBLISHERS IS AN IMPRINT OF ELSEVIER

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Advanced Graphics Programming Using OpenGL

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The Morgan Kaufmann Series in Computer Graphics and Geometric Modeling

Series Editor: Brian A. Barsky University of California, Berkeley

This series publishes the finest works for the accomplished and aspiring graphics professional. The series includes intermediate

and advanced textbooks, graphics programming books, surveys of important new areas and methods, and reference works.

Advanced Graphics Programming Using OpenGL

Tom McReynolds and David Blythe

Digital Geometry Geometric Methods for Digital

Picture Analysis

Rienhard Klette and Azriel Rosenfeld

Digital Video and HDTV Algorithms and Interfaces

Charles Poynton

Real-Time Shader Programming

Ron Fosner

Complete Maya Programming:

An Extensive Guide to MEL and the C++ API

David Gould

MEL Scripting for Maya Animators

Mark R. Wilkins and Chris Kazmier

Digital Video and HDTV Algorithms and Interfaces

Charles Poynton

Texturing & Modeling:

A Procedural Approach, Third Edition

David S. Ebert, F. Kenton Musgrave, Darwyn Peachey,

Ken Perlin, and Steven Worley

Geometric Tools for Computer Graphics

Philip Schneider and David Eberly

Understanding Virtual Reality:

Interface, Application, and Design

William Sherman and Alan Craig

Jim Blinn’s Corner: Notation, Notation, Notation

Jim Blinn

Level of Detail for 3D Graphics:

David Luebke, Martin Reddy, Jonathan D. Cohen,

Amitabh Varshney, Benjamin Watson, and

Robert Huebner

Pyramid Algorithms: A Dynamic Programming

Approach to Curves and Surfaces for Geometric

Modeling

Ron Goldman

Non-Photorealistic Computer Graphics:

Modeling, Rendering, and Animation

Thomas Strothotte and Stefan Schlechtweg

Curves and Surfaces for CAGD: A Practical Guide,

Fifth Edition

Gerald Farin

Subdivision Methods for Geometric Design:

A Constructive Approach

Joe Warren and Henrik Weimer

Computer Animation: Algorithms and Techniques

Rick Parent

The Computer Animator’s Technical Handbook

Lynn Pocock and Judson Rosebush

Advanced RenderMan:

Creating CGI for Motion Pictures

Anthony A. Apodaca and Larry Gritz

Curves and Surfaces in Geometric Modeling:

Theory and Algorithms

Jean Gallier

Andrew Glassner’s Notebook:

Recreational Computer Graphics

Andrew S. Glassner

Warping and Morphing of Graphical Objects

Jonas Gomes, Lucia Darsa, Bruno Costa, and Luiz Velho

Jim Blinn’s Corner: Dirty Pixels

Jim Blinn

Rendering with Radiance:

The Art and Science of Lighting Visualization

Greg Ward Larson and Rob Shakespeare

Introduction to Implicit Surfaces

Edited by Jules Bloomenthal

Jim Blinn’s Corner:

A Trip Down the Graphics Pipeline

Jim Blinn

Interactive Curves and Surfaces:

A Multimedia Tutorial on CAGD

Alyn Rockwood and Peter Chambers

Wavelets for Computer Graphics:

Theory and Applications

Eric J. Stollnitz, Tony D. DeRose, and David H. Salesin

Principles of Digital Image Synthesis

Andrew S. Glassner

Radiosity & Global Illumination

François X. Sillion and Claude Puech

Knotty: A B-Spline Visualization Program

Jonathan Yen

User Interface Management Systems:

Models and Algorithms

Dan R. Olsen, Jr.

Making Them Move: Mechanics, Control, and Animation

of Articulated Figures

Edited by Norman I. Badler, Brian A. Barsky, and

David Zeltzer

Geometric and Solid Modeling: An Introduction

Christoph M. Hoffmann

An Introduction to Splines for Use in Computer Graphics

and Geometric Modeling

Richard H. Bartels, John C. Beatty, and Brian A. Barsky

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Publishing Services Manager: Simon Crump

Project Manager: Brandy Lilly

Editorial Coordinator: Mona Buehler

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ISBN: 1-55860-659-9

For information on all Morgan Kaufmann publications,

visit our Web site at www.mkp.com or www.books.elsevier.com

Printed in China

10 9 8 7 6 5 4 3 2 1

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To my friends and colleagues from Silicon Graphics; it was a fabulous time and place to

learn about 3D graphics. – DB

To Ede Forney and Harry McGinnis; you were there when it counted. – TM

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Contents

Preface xxiii

Acknowledgments xxvii

Biographies xxviii

PART I

Concepts 1

CHAPTER 1

Geometry Representation and Modeling 3

1.1 Polygonal Representation 3

1.2 Decomposition and Tessellation 4

1.3 Shading Normals 8

1.3.1 Smooth Shading 9

1.3.2 Vertex Winding Order 11

1.4 Triangle Stripping 12

1.4.1 Greedy Tri-stripping 13

1.5 Vertices and Vertex Arrays 14

1.5.1 Vertex Buffer Objects 15

1.5.2 Triangle Lists 16

1.6 Modeling vs. Rendering Revisited 17

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CHAPTER 2

3D Transformations 19

2.1 Data Representation 19

2.2 Overview of the Transformation Pipeline 20

2.2.1 Object Space and the Modelview Transform 20

2.2.2 Eye Space and Projection Transform 21

2.2.3 Clip Space and Perspective Divide 22

2.2.4 NDC Space and the Viewport Transform 22

2.2.5 Window Space 23

2.3 Normal Transformation 23

2.4 Texture Coordinate Generation and Transformation 25

2.4.1 Texture Matrix 25

2.4.2 Texture Coordinate Generation 25

2.5 Modeling Transforms 27

2.6 Visualizing Transform Sequences 28

2.7 Projection Transform 30

2.8 The Z Coordinate and Perspective Projection 30

2.8.1 Z Coordinates and Fog 32

2.9 Vertex Programs 32

2.10 Summary 34

CHAPTER 3

Color, Shading, and Lighting 35

3.1 Representing Color 35

3.1.1 Resolution and Dynamic Range 36

3.1.2 Gamma 37

3.1.3 Alpha 39

3.1.4 Color Index 39

3.2 Shading 40

3.3 Lighting 43

3.3.1 Intensities, Colors, and Materials 46

3.3.2 Light Source Properties 47

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3.3.3 Material Properties 49

3.3.4 Vertex and Fragment Lighting 50

3.4 Fixed-Point and Floating-Point Arithmetic 53

3.4.1 Biased Arithmetic 54

3.5 Summary 56

CHAPTER 4

Digital Images and Image Manipulation 57

4.1 Image Representation 57

4.2 Digital Filtering 60

4.3 Convolution 62

4.4 Images in OpenGL 63

4.5 Positioning Images 65

4.6 Pixel Store Operations 65

4.7 Pixel Transfer Operations 67

4.7.1 Scale and Bias 67

4.7.2 Pixel Mapping Operations 67

4.8 ARB Imaging Subset 68

4.8.1 Convolution 68

4.8.2 Color Matrix Transform 68

4.8.3 Histogram 69

4.8.4 MinMax 70

4.8.5 Color Tables 70

4.8.6 Blend Equation and Constant Color Blending 71

4.9 Off-Screen Processing 72

4.10 Summary 72

CHAPTER 5

Texture Mapping 73

5.1 Loading Texture Images 73

5.1.1 Texture Borders 74

5.1.2 Internal Texture Formats 75

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5.1.3 Compressed Textures 76

5.1.4 Proxy Textures 77

5.2 Texture Coordinates 77

5.2.1 Texture Coordinate Generation and Transformation 79

5.3 Loading Texture Images from the Frame Buffer 79

5.4 Environment Mapping 80

5.4.1 Generating Environment Map Texture Coordinates 81

5.4.2 Texture Maps Used in Environment Mapping 82

5.4.3 Cube Mapping 83

5.4.4 Sphere Mapping 85

5.5 3D Texture 88

5.5.1 Using 3D Textures to Render Solid Materials 89

5.6 Filtering 90

5.7 Additional Control of Texture Level of Detail 91

5.8 Texture Objects 93

5.9 Multitexture 95

5.9.1 Multitexture Model 96

5.9.2 Multitexture Texture Environments 97

5.10 Texture Environment 98

5.10.1 Advanced Texture Environment Functionality 99

5.10.2 Fragment Programs 100

5.11 Summary 102

CHAPTER 6

Rasterization and Fragment Processing 103

6.1 Rasterization 104

6.1.1 Rasterization Consistency 105

6.1.2 Z-Fighting 105

6.1.3 Bitmaps and Pixel Rectangles 107

6.1.4 Texture, Color, and Depth Interpolation 108

6.1.5 w Buffering 109

6.2 Fragment Operations 110

6.2.1 Multisample Operations 111

6.2.2 Alpha Test 111

6.2.3 Stencil Test 111

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6.2.4 Blending 112

6.2.5 Logic Op 114

6.3 Framebuffer Operations 115

6.3.1 Accumulation Buffer 116

6.4 Summary 117

CHAPTER 7

Window System and Platform Integration 119

7.1 Renderer and Window State 120

7.2 Address Space and Threads 121

7.3 Anatomy of a Window 122

7.3.1 Overlay and Underlay Windows 122

7.3.2 Multiple Displays 123

7.4 Off-Screen Rendering 124

7.4.1 GLX Pbuffers 125

7.4.2 WGL Pbuffers 126

7.5 Rendering to Texture Maps 126

7.6 Direct and Indirect Rendering 127

CHAPTER 8

OpenGL Implementations 129

8.1 OpenGL Versions 129

8.2 OpenGL Extensions 131

8.3 OpenGL ES for Embedded Systems 131

8.3.1 Embedded Profiles 132

8.3.2 Common and Common-Lite Profiles 133

8.3.3 Safety Critical Profile 136

8.3.4 OpenGL ES Revisions 136

8.4 OpenGL Pipeline Evolution 137

8.5 Hardware Implementations of the Pipeline 138

8.5.1 Rasterization Acceleration 138

8.5.2 Primitive Setup Acceleration 141

8.5.3 Transform and Lighting Acceleration 141

8.5.4 Pipeline Balance 142

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8.5.5 Parallelism Opportunities 142

8.5.6 Reordering the Pipeline 149

8.5.7 Mixed Software and Hardware Implementations 150

8.6 The Future 151

P A R T II

Basic Techniques 153

CHAPTER 9

Multiple Rendering Passes 155

9.1 Invariance 155

9.2 Multipass Overview 156

9.3 The Multipass Toolbox 159

9.3.1 Arithmetic Operations 159

9.3.2 Arbitrary Functions 160

9.3.3 Conditionals 161

9.3.4 Variables 162

9.3.5 Parameters 163

9.4 Multipass Limitations 165

9.5 Multipass vs. Micropass 165

9.5.1 Multitexture 166

9.6 Deferred Shading 167

9.7 Summary 167

CHAPTER 10

Antialiasing 169

10.1 Full-Scene Antialiasing 170

10.2 Supersampling 171

10.2.1 Supersampling by Overdrawing 172

10.2.2 Supersampling with the Accumulation Buffer 173

10.2.3 Multisample Antialiasing 175

10.2.4 Drawbacks 176

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10.3 Area Sampling 177

10.4 Line and Point Antialiasing 178

10.5 Antialiasing with Textures 180

10.6 Polygon Antialiasing 181

10.7 Temporal Antialiasing 182

10.7.1 Motion Blur 183

10.8 Summary 184

CHAPTER 11

Compositing, Blending, and Transparency 185

11.1 Combining Two Images 185

11.1.1 Compositing 186

11.1.2 Compositing Multiple Images 187

11.1.3 Alpha Division 190

11.2 Other Compositing Operators 190

11.3 Keying and Matting 192

11.4 Blending Artifacts 192

11.4.1 Arithmetic Errors 192

11.4.2 Blending with the Accumulation Buffer 193

11.4.3 Approximation Errors 193

11.4.4 Gamma Correction Errors 193

11.5 Compositing Images with Depth 194

11.6 Other Blending Operations 195

11.7 Dissolves 196

11.8 Transparency 199

11.9 Alpha-Blended Transparency 200

11.9.1 Dynamic Object Transparency 202

11.9.2 Transparency Mapping 203

11.9.3 Transparency Sorting 204

11.9.4 Depth Peeling 205

11.10 Screen-Door Transparency 205

11.10.1 Multisample Transparency 207

11.11 Summary 208

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CHAPTER 12

Image Processing Techniques 211

12.1 OpenGL Imaging Support 211

12.2 Image Storage 212

12.3 Point Operations 213

12.3.1 Color Adjustment 213

12.3.2 Interpolation and Extrapolation 213

12.3.3 Scale and Bias 215

12.3.4 Thresholding 215

12.3.5 Conversion to Luminance 216

12.3.6 Manipulating Saturation 216

12.3.7 Rotating Hue 218

12.3.8 Color Space Conversion 219

12.4 Region-based Operations 223

12.4.1 Contrast Stretching 224

12.4.2 Histogram Equalization 224

12.5 Reduction Operations 225

12.6 Convolution 227

12.6.1 Separable Filters 227

12.6.2 Convolutions Using the Accumulation Buffer 228

12.6.3 Convolution Using Extensions 230

12.6.4 Useful Convolution Filters 230

12.6.5 Correlation and Feature Detection 233

12.7 Geometric Operations 235

12.7.1 Pixel Zoom 235

12.7.2 Scaling Using Texture Mapping 236

12.7.3 Rotation Using Texture Mapping 237

12.7.4 Distortion Correction 237

12.8 Image-Based Depth of Field 238

12.9 High Dynamic Range Imaging 241

12.9.1 Dynamic Range 241

12.9.2 Tone Mapping 242

12.9.3 Modeling Adaptation 245

12.10 Summary 245

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CHAPTER 13

Basic Transform Techniques 247

13.1 Computing Inverse Transforms Efficiently 247

13.2 Stereo Viewing 249

13.3 Depth of Field 252

13.4 Image Tiling 254

13.5 Billboarding Geometry 257

13.6 Texture Coordinate vs. Geometric Transformations 261

13.6.1 Direct Vertex to Texture Coordinate Mapping 263

13.6.2 Overlaying an Entire Scene with a Texture 263

13.6.3 Overlaying a Scene with an Independent Texture

Projection 264

13.7 Interpolating Vertex Components through a Perspective

Transformation 265

13.7.1 Transforming Vertices in the Application 265

13.7.2 Interpolating Vertex Components 266

13.7.3 Computing LOD 267

13.8 Summary 268

CHAPTER 14

Texture Mapping Techniques 269

14.1 Loading Texture Images into a Framebuffer 270

14.2 Optimizing Texture Coordinate Assignment 270

14.3 3D Textures 271

14.4 Texture Mosaics 274

14.5 Texture Tiling 277

14.6 Texture Paging 279

14.6.1 Texture Subimage Loading 282

14.6.2 Paging Images in System Memory 285

14.6.3 Hardware Support for Texture Paging 286

14.7 Prefiltered Textures 287

14.7.1 Computing Texel Aspect Ratios 288

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14.8 Dual-Paraboloid Environment Mapping 291

14.8.1 The Mathematics of Dual-Paraboloid Maps 291

14.8.2 Using Dual-Paraboloid Maps 294

14.8.3 OpenGL Dual-Paraboloid Support 296

14.9 Texture Projection 296

14.10 Texture Color Coding and Contouring 298

14.11 2D Image Warping 300

14.12 Texture Animation 302

14.13 Detail Textures 306

14.13.1 Signed Intensity Detail Textures 309

14.13.2 Creating Detail Textures 311

14.14 Texture Sharpening 312

14.15 Mipmap Generation 313

14.16 Texture Map Limits 315

14.17 Summary 316

CHAPTER 15

Lighting Techniques 317

15.1 Limitations in Vertex Lighting 317

15.1.1 Static and Adaptive Tessellation 319

15.1.2 Local Light and Spotlight Attenuation 320

15.2 Fragment Lighting Using Texture Mapping 321

15.3 Spotlight Effects Using Projective Textures 322

15.4 Specular Lighting Using Environment Maps 325

15.4.1 Multitexture 326

15.5 Light Maps 327

15.5.1 2D Texture Light Maps 327

15.5.2 3D Texture Light Maps 330

15.6 BRDF-based Lighting 332

15.7 Reflectance Maps 332

15.7.1 Gloss Maps 332

15.7.2 Emission Maps 334

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