OpenGL 4.0 Shading Language Cookbook

340 Pages·2011·9.153 MB·

by  David Wolff

OpenGL 4.0 Shading
Language Cookbook
Over 60 highly focused, practical recipes to maximize your
use of the OpenGL Shading Language
David Wolff
BIRMINGHAM - MUMBAI
OpenGL 4.0 Shading Language Cookbook
Copyright © 2011 Packt Publishing
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First published: July 2011
Production Reference: 1180711
Published by Packt Publishing Ltd.
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Olton
Birmingham, B27 6PA, UK.
ISBN 978-1-849514-76-7
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Cover Image by Fillipo ([email protected])
Credits
Author Project Coordinator
David Wolff Srimoyee Ghoshal
Reviewers Proofreader
Martin Christen Bernadette Watkins
Nicolas Delalondre
Indexer
Markus Pabst
Hemangini Bari
Brandon Whitley
Graphics
Acquisition Editor Nilesh Mohite
Usha Iyer
Valentina J. D’silva
Development Editor
Production Coordinators
Chris Rodrigues
Kruthika Bangera
Technical Editors Adline Swetha Jesuthas
Kavita Iyer
Cover Work
Azharuddin Sheikh
Kruthika Bangera
Copy Editor
Neha Shetty
About the Author
David Wolff is an associate professor in the Computer Science and Computer
Engineering Department at Pacific Lutheran University (PLU). He received his PhD in
Physics from Oregon State University. He has a passion for computer graphics and
the intersection between art and science. He has been teaching computer graphics to
undergraduates at PLU for over 10 years, using OpenGL.
Special thanks to Brandon Whitley for interesting discussions and helpful
insights during the writing of this book. His help has been incredibly valuable.
Thanks also to all of the reviewers and editors for their help.

I'd also like to thank my parents for a lifetime of support, love and
encouragement.
About the Reviewers
Martin Christen graduated with a Computer Science degree. Today, he is a senior
research associate at the Institute of Geomatics Engineering of the University of Applied
Sciences Northwestern (FHNW) Switzerland. He is the lead developer of the open source
virtual globe engine (http://www.openwebglobe.org).
Previously, he was software developer in the fields of 3D geoinformation and in 3D
computer game development. His main research interests are GPU-programming, parallel
computing, terrain-rendering, and 3D graphics engine architecture.
Nicolas Delalondre has been working on 3D computer graphics software for more
than ten years mainly in OpenGL on desktop and mobile devices. Currently, he is a
freelance developer at Digital Mind and an associate at Rhino Terrain where he develops
geomodeling and meshing algorithms. Before joining Rhino Terrain, Nicolas was a
3D software engineer at Bionatics, a French startup, developing OpenGL engine and
algorithms for geographic information system (GIS). Prior to working with Bionatics, he
worked for INRIA (French research institute in computer science) in the radiosity field.
Nicolas has a Master's degree in Computer Science from EFREI, France.
Markus Pabst has been working with OpenGL since 2002. He works in the digital
mapping industry and has worked with the desktop and embedded versions of OpenGL.
Since 2007, he has been leading a team of software engineers developing an embedded
OpenGL-based cockpit display system for the Airbus A400M aircraft certified against DO-
178B Level C standard. In 2005, he began teaching OpenGL at the German University of
Applied Sciences Ravensburg-Weingarten.
Markus received his university degree in Multimedia Technologies from the Technical
University of Ilmenau, in 2002. In the summer, you may find Markus on a sailing boat in
southern Germany.
Brandon Whitley worked for four years as a graphics programmer for Zipper
Interactive, a Sony Computer Entertainment Worldwide Studio. He earned his Masters
degree in Computer Science from Georgia Institute of Technology. While obtaining his
undergraduate degree at Pacific Lutheran University, he was inspired by the author
of this book to pursue a career in computer graphics. Brandon is currently a graphics
programmer at Bungie, creators of the Halo series.
I would like to thank my wife, Katie, and my son, Parker, for their love
and support.
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Table of Contents
Preface 1
Chapter 1: Getting Started with GLSL 4.0 5
Introduction 6
Using the GLEW Library to access the latest OpenGL functionality 8
Using the GLM library for mathematics 10
Determining the GLSL and OpenGL version 13
Compiling a shader 15
Linking a shader program 18
Sending data to a shader using per-vertex attributes and vertex buffer objects 22
Getting a list of active vertex input attributes and indices 29
Sending data to a shader using uniform variables 31
Getting a list of active uniform variables 35
Using uniform blocks and uniform buffer objects 37
Building a C++ shader program class 43
Chapter 2: The Basics of GLSL Shaders 47
Introduction 47
Implementing diffuse, per-vertex shading with a single point light source 50
Implementing per-vertex ambient, diffuse, and specular (ADS) shading 55
Using functions in shaders 62
Implementing two-sided shading 65
Implementing flat shading 69
Using subroutines to select shader functionality 71
Discarding fragments to create a perforated look 76
Chapter 3: Lighting, Shading Effects, and Optimizations 81
Introduction 81
Shading with multiple positional lights 82
Shading with a directional light source 84
Using per-fragment shading for improved realism 88