OpenGL(R) Shading Language

by Rost, Randi J.

• ISBN13: 9780321197894
• ISBN10: 0321197895
• Format: Paperback
• Copyright: 2004-01-01
• Publisher: Addison-Wesley Professional

Summary

- Shading languages are the most important new development in graphics programming in years - The author is at the very centre of the activity surrounding the OpenGL Shading Language - Both a tutorial and a reference, with lots of practical examples

Table of Contents

Foreword	p. xxiii
Foreword to the First Edition	p. xxvii
Preface	p. xxxi
About the Author	p. xxxvii
About the Contributors	p. xxxix
Acknowledgments	p. xli
Review of OpenGL Basics	p. 1
OpenGL History	p. 1
OpenGL Evolution	p. 3
Execution Mode	p. l4
The Frame Buffer	p. 5
State	p. 8
Processing Pipeline	p. 8
Drawing Geometry	p. 9
Geometry Specification	p. 9
Per-Vertex Operations	p. 12
Primitive Assembly	p. 14
Primitive Processing	p. 14
Rasterization	p. 15
Fragment Processing	p. 16
Per-Fragment Operations	p. 16
Frame Buffer Operations	p. 17
Drawing Images	p. 18
Pixel Unpacking	p. 19
Pixel Transfer	p. 19
Rasterization and Back-End Processing	p. 20
Read Control	p. 20
Coordinate Transforms	p. 21
Texturing	p. 26
Summary	p. 31
Further Information	p. 32
Basics	p. 35
Introduction to the OpenGL Shading Language	p. 35
Why Write Shaders?	p. 37
OpenGL Programmable Processors	p. 38
	p. 40
	p. 43
	p. 47
Language Design Considerations	p. 47
C Basis	p. 50
Additions to C	p. 50
Additions from C++	p. 52
C Features Not Supported	p. 53
Other Differences	p. 53
System Overview	p. 54
Driver Model	p. 54
OpenGL Shading Language Compiler/Linker	p. 56
OpenGL Shading Language API	p. 57
Key Benefits	p. 59
Summary	p. 61
Further Information	p. 63
Language Definition	p. 65
Example Shader Pair	p. 65
Data Types	p. 67
Scalars	p. 67
Vectors	p. 69
Matrices	p. 70
Samplers	p. 71
Structures	p. 72
Arrays	p. 73
Void	p. 74
Declarations and Scope	p. 74
Type Matching and Promotion	p. 75
Initializers and Constructors	p. 75
Type Conversions	p. 77
Qualifiers and Interface to a Shader	p. 78
Attribute Qualifiers	p. 79
Uniform Qualifiers	p. 79
Varying Qualifiers	p. 79
Constant Qualifiers	p. 80
Absent Qualifier	p. 81
Flow Control	p. 82
Functions	p. 82
Calling Conventions	p. 83
Built-in Functions	p. 84
Operations	p. 85
Indexing	p. 86
Swizzling	p. 87
Component-wise Operation	p. 87
Preprocessor	p. 90
Preprocessor Expressions	p. 93
Error Handling	p. 94
Summary	p. 95
Further Information	p. 95
The OpenGL Programmable Pipeline	p. 97
The Vertex Processor	p. 98
Vertex Attributes	p. 99
Uniform Variables	p. 100
Special Output Variables	p. 101
Built-in Varying Variables	p. 102
User-Defined Varying Variables	p. 103
The Fragment Processor	p. 104
Varying Variables	p. 104
Uniform Variables	p. 105
Special Input Variables	p. 106
Special Output Variables	p. 107
Built-in Uniform Variables	p. 108
Built-in Constants	p. 113
Interaction with OpenGL Fixed Functionality	p. 114
Two-Sided Color Mode	p. 114
Point Size Mode	p. 115
Clipping	p. 116
Raster Position	p. 117
Position Invariance	p. 117
Texturing	p. 118
Summary	p. 120
Further Information	p. 120
Built-in Functions	p. 123
Angle and Trigonometry Functions	p. 124
Exponential Functions	p. 126
Common Functions	p. 126
Geometric Functions	p. 136
Matrix Functions	p. 138
Vector Relational Functions	p. 139
Texture Access Functions	p. 141
Fragment Processing Functions	p. 144
Noise Functions	p. 145
Summary	p. 147
Further Information	p. 147
Simple Shading Example	p. 149
Brick Shader Overvie
Table of Contents provided by Publisher. All Rights Reserved.

Excerpts

For just about as long as there has been graphics hardware, there has been programmable graphics hardware. Over the years, building flexibility into graphics hardware designs has been a necessary way of life for hardware developers. Graphics APIs continue to evolve, and because a hardware design can take two years or more from start to finish, the only way to guarantee a hardware product that can support the then-current graphics APIs at its release is to build in some degree of programmability from the very beginning. Until recently, the realm of programming graphics hardware belonged to just a few people, mainly researchers and graphics hardware driver developers. Research into programmable graphics hardware has been taking place for many years, but the point of this research has not been to produce viable hardware and software for application developers and end users. The graphics hardware driver developers have focused on the immediate task of providing support for the important graphics APIs of the time: PHIGS, PEX, Iris GL, OpenGL, Direct3D, and so on. Until recently, none of these APIs exposed the programmability of the underlying hardware, so application developers have been forced into using the fixed functionality provided by traditional graphics APIs. Hardware companies have not exposed the programmable underpinnings of their products because there is a high cost of educating and supporting customers to use low-level, device-specific interfaces and because these interfaces typically change quite radically with each new generation of graphics hardware. Application developers who use such a device-specific interface to a piece of graphics hardware face the daunting task of updating their software for each new generation of hardware that comes along. And forget about supporting the application on hardware from multiple vendors! As we move into the 21 century, some of these fundamental tenets about graphics hardware are being challenged. Application developers are pushing the envelope as never before and demanding a variety of new features in hardware in order to create more and more sophisticated onscreen effects. As a result, new graphics hardware designs are more programmable than ever before. Standard graphics APIs have been challenged to keep up with the pace of hardware innovation. For OpenGL, the result has been a spate of extensions to the core API as hardware vendors struggle to support a range of interesting new features that their customers are demanding. So we are standing today at a crossroads for the graphics industry. A paradigm shift is occurring, one that is taking us from the world of rigid, fixed functionality graphics hardware and graphics APIs to a brave new world where the visual processing unit, or VPU (i.e., graphics hardware), is as important as the central processing unit, or CPU. The VPU will be optimized for processing dynamic media such as 3D graphics and video. Highly parallel processing of floating point data will be the primary task for VPUs, and the flexibility of the VPU will mean that it can also be used to process data other than a stream of traditional graphics commands. Applications can take advantage of the capabilities of both the CPU and the VPU, utilizing the strengths of each to perform the task at hand optimally. This book describes how graphics hardware programmability is exposed through a high-level language in the leading cross-platform 3D graphics API: OpenGL. This language, the OpenGL Shading Language, allows applications to take total control over the most important stages of the graphics processing pipeline. No longer restricted to the graphics rendering algorithms and formulas chosen by hardware designers and frozen in silicon, software developers are beginning to use this programmability to create stunning effects in real-time. Intended Audience The primary audience for this book is application programmers that a