OpenGL(R) Shading Language

Until recently, application developers have had no choice but to use the graphics hardware as built by hardware developers. The programming interfaces (APIs) simply exposed the underlying capabilities of the hardware. If the hardware didn't do something quite the way an application wanted it done, there was no alternative but to accept what the hardware could do. More recently, graphics hardware has become more flexible. Developers have been eager to exploit this flexibility. Within the last year or so, it's become clear that the right answer for OpenGL is to expose the new functionality in the form of a high-level programming language - the new OpenGL Shading Language, developed by 3Dlavis, Inc., is the answer. This book is the official guide to this new language. It is both a tutorial and a reference, and is filled with many practical examples that will help developers learn the language as well as create shaders to suit their own needs. The author is at the very center of this technology, serving on the OpenGL ARB and leading the team at 3Dlabs responsible for defining and implementing the next iteration of OpenGL. This is the one book all graphics developers will need in order to learn about this important new advance in graphics programming.

User review
Not as useful as they're saying
By and large, the reviews here have found this book to be a great resource, to have helpful examples, and perhaps is THE book to have for all things GLSL.

After about chapter 3, it stops living up to the hype.

Up to that point, it does what it needs to do: it gives a decent coverage of the various parts of the language. It then provides one example that actually works.

It is after that that you begin to see that there is a great deal of synergy required between GLSL applications and OpenGL itself. The examples provide (mostly) working shaders without even a hint of the OpenGL code required to interface with them properly, or even what some of the required parts of the shaders are (largely textures described by name only). Also conspicuously absent from this tome is any CD of examples, a common feature of computer texts. In short, if you don't already know what you're doing for anything remotely complex, this book isn't going to tell you.

Save your money.

User review
Orange Book
I definitely recommend this book for anyone working with OpenGL's new Shading Language. I would, however, say that probably the most difficult part of working with GLSL is getting it working in the first place. Especially on Linux, this is somewhat confusing - some cards support GL 2.0, some don't, but still support the GLSL if using the ARB function calls. I would also make sure to point out to new users that GLEW is close to essential when working with the GLSL - you can download it from sourceforge. It might be worth mentioning in future versions of the book, along with ARB functions which are the same as the GLSL standard functions shown in the book.

User review
A little chunky, but a good necessary work
I'm not a fan of the 'group of papers' style of book. But this book pulls it off nicely. The text is consistenly good throughout. And the illustrations and formulas are high quality and presented nicely.

I would have liked full color throughout, but I accept that it would have been cost prohibitive on a book of this heft. Speaking of heft, yeah, this is a doorstop of a book. I think some of the text could have been edited down and the formatting tightened up to reduce bulk.

User review
Excellent guide to OpenGL Shading Language
The recent trend in graphics hardware has been to replace fixed functionality with programmability in areas that have grown exceedingly complex (e.g., vertex processing and fragment processing). The OpenGL Shading Language has been designed to allow application programmers to express the processing that occurs at those programmable points of the OpenGL pipeline. Independently compilable units that are written in this language are called shaders. A program is a set of shaders that are compiled and linked together. The OpenGL Shading Language is based on ANSI C and many of the features have been retained except when they conflict with performance or ease of implementation. This shading language is without a doubt the most important addition to OpenGL since its inception, and this book provides an excellent guide to programming with it. The author was one of the primary contributors to the development of the language, and he provides a well-written and insightful explanation of the language and its use.
The book begins with a review of OpenGL basics, followed by an introduction to shaders and how they fit into the pipeline. It then covers the language itself, including data types, operators, interaction with the OpenGL state machine and fixed function pipeline, built-in functions, and more. It also introduces and explains the OpenGL APIs needed to use shaders.
The last half of the book focuses on shader development, including general process and workflow, and coverage of many specific techniques, such as procedural textures and GPU-based animation. It even includes a section on implementing the fixed function pipeline using shaders. The book ends with a handy comparison of OpenGL Shading Language with other shading languages, such as Cg, HLSL, and Renderman and a couple of appendices providing a language grammar and API reference.
I particularly liked chapters 6 through 8, which take you from a simple shading example -`brick`- through the specific steps of shader development that you would need to master regardless of the API you are using. Also the chapters on procedural textures and noise and the accompanying code examples helped clear up some matters that were murky when I read `Texturing & Modeling: A Procedural Approach` by Ebert et al. In summary, I highly recommend this book to anyone interested in implementing software shading, both from the standpoint of OpenGL and from the standpoint of the design process itself. I notice that Amazon does not show the table of contents for the second edition, so I do that here:
Chapter 1. REVIEW OF OPENGL BASICS
OpenGL History; OpenGL Evolution; Execution Mode; The Frame Buffer; State; Processing Pipeline; Drawing Geometry; Drawing Images; Coordinate Transforms; Texturing;

Chapter 2. BASICS
Introduction to the OpenGL Shading Language; Why Write Shaders?; OpenGL Programmable Processors; Language Overview; System Overview; Key Benefits;

Chapter 3. LANGUAGE DEFINITION
Example Shader Pair; Data Types; Initializers and Constructors; Type Conversions; Qualifiers and Interface to a Shader; Flow Control; Operations; Preprocessor; Preprocessor Expressions; Error Handling;

Chapter 4. THE OPENGL PROGRAMMABLE PIPELINE
The Vertex Processor; The Fragment Processor; Built-in Uniform Variables; Built-in Constants; Interaction with OpenGL Fixed Functionality;

Chapter 5. BUILT-IN FUNCTIONS
Angle and Trigonometry Functions; Exponential Functions; Common Functions; Geometric Functions; Matrix Functions; Vector Relational Functions; Texture Access Functions; Fragment Processing Functions; Noise Functions;

Chapter 6. SIMPLE SHADING EXAMPLE
Brick Shader Overview; Vertex Shader; Fragment Shader; Observations;

Chapter 7 OPENGL SHADING LANGUAGE API
Obtaining Version Information; Creating Shader Objects; Compiling Shader Objects; Linking and Using Shaders; Cleaning Up; Query Functions; Specifying Vertex Attributes; Specifying Uniform Variables; Samplers; Multiple Render Targets; Development Aids; Implementation-Dependent API Values; Application Code for Brick Shaders;

Chapter 8. SHADER DEVELOPMENT
General Principles; Performance Considerations; Shader Debugging; Shader Development Tools; Scene Graphs;

Chapter 9. EMULATING OPENGL FIXED FUNCTIONALITY
Transformation; Light Sources; Material Properties and Lighting; Two-Sided Lighting; No Lighting; Fog; Texture Coordinate Generation; User Clipping; Texture Application;

Chapter 10. STORED TEXTURE SHADERS
Access to Texture Maps from a Shader; Simple Texturing Example; Multitexturing Example; Cube Mapping Example; Another Environment Mapping Example; Glyph Bombing;

Chapter 11. PROCEDURAL TEXTURE SHADERS
Regular Patterns; Toy Ball; Lattice; Bump Mapping;

Chapter 12. LIGHTING
Hemisphere Lighting; Image-Based Lighting; Lighting with Spherical Harmonics; The *erLight Shader;

Chapter 13. SHADOWS
Ambient Occlusion; Shadow Maps; Deferred Shading for Volume Shadows;

Chapter 14. SURFACE CHARACTERISTICS
Refraction; Diffraction; BRDF Models; Polynomial Texture Mapping with BRDF Data;

Chapter 15. NOISE
Noise Defined; Noise Textures; Trade-offs; A Simple Noise Shader; Turbulence; Granite; Wood;

Chapter 16. ANIMATION
On/Off; Threshold; Translation; Morphing; Other Blending Effects; Vertex Noise; Particle Systems; Wobble;

Chapter 17. ANTIALIASING PROCEDURAL TEXTURES
Sources of Aliasing; Avoiding Aliasing; Increasing Resolution; Antialiased Stripe Example; Frequency Clamping;

Chapter 18. NON-PHOTOREALISTIC SHADERS
Hatching Example; Technical Illustration Example; Mandelbrot Example;

Chapter 19. SHADERS FOR IMAGING
Geometric Image Transforms; Mathematical Mappings; Lookup Table Operations; Color Space Conversions; Image Interpolation and Extrapolation; Blend Modes;

Chapter 20. REALWORLDZ
Features; RealWorldz Internals; Implementation; Atmospheric Effects; Ocean; Clouds;

Chapter 21. LANGUAGE COMPARISON
Chronology of Shading Languages; RenderMan; OpenGL Shader (ISL); HLSL; Cg;
Appendix A. Language Grammar
Appendix B. API Function Reference




User review
do your own shading?!
Twenty years ago, I used to program graphics on an Evans and Sutherland PS340. It was then one of the top of the line graphics computers (costing $100k). It could labouriously do shading, but only Phong and Gouraud. Nowadays, many PCs have this ability, and much faster. But a problem still persists, where often the shading methods are restricted to what is implemented on the graphics chips.

In contrast, you have the approach in this definitive book on OpenGL Shading Language. This lets you implement in your code, shading routines of your own devising. To be sure, given the same shading method, one done in this language, and one in the hardware, then the latter will have better performance. But it turns out that today's computers are fast enough, and have enough RAM, that the difference in response might not be appreciable.

The book describes an extensive set of built-in convenience functions that come with the language. And the language's API is explained in detail. The author rightly recommends that you come at it with some experience in the standard OpenGL.

Since the language is still quite new, you are more or less on your own, when looking at development tools. This dearth is expected to be remedied in a few years. But right now, you'll have to rely on your wits. Along with a chapter that gives general principles of how you should develop your own shader. What may be even more use, however, is the second half of the book. Devoted to case studies of many shaders. Understanding these may be more beneficial than any IDE.

Oh, as you might expect from a graphics book, there is a lovely set of colour plates in the middle of the book, showing what custom shaders can do. Treat it as inspiration if you wish.