Sellers G. - OpenGL Superbible: Comprehensive Tutorial and Reference

ePUB is an open, industry-standard format for eBooks. However, support of ePUB and its many features varies across reading devices and applications. Use your device or app settings to customize the presentation to your liking. Settings that you can customize often include font, font size, single or double column, landscape or portrait mode, and figures that you can click or tap to enlarge. For additional information about the settings and features on your reading device or app, visit the device manufacturers Web site.

Many titles include programming code or configuration examples. To optimize the presentation of these elements, view the eBook in single-column, landscape mode and adjust the font size to the smallest setting. In addition to presenting code and configurations in the reflowable text format, we have included images of the code that mimic the presentation found in the print book; therefore, where the reflowable format may compromise the presentation of the code listing, you will see a Click here to view code image link. Click the link to view the print-fidelity code image. To return to the previous page viewed, click the Back button on your device or app.

Seventh Edition

Comprehensive Tutorial
and Reference

Graham Sellers
Richard S. Wright, Jr.
Nicholas Haemel

New York Boston Indianapolis San Francisco
Toronto Montreal London Munich Paris Madrid
Capetown Sydney Tokyo Singapore Mexico City

Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and the publisher was aware of a trademark claim, the designations have been printed with initial capital letters or in all capitals.

OpenGL is a registered trademark of Silicon Graphics Inc. and is used by permission of Khronos.

The authors and publisher have taken care in the preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein.

For information about buying this title in bulk quantities, or for special sales opportunities (which may include electronic versions; custom cover designs; and content particular to your business, training goals, marketing focus, or branding interests), please contact our corporate sales department at or (800) 382-3419.

For government sales inquiries, please contact .

For questions about sales outside the United States, please contact .

Visit us on the Web: informit.com/aw

Library of Congress Cataloging-in-Publication Data
Wright, Richard S., Jr., 1965- author.
OpenGL superBible : comprehensive tutorial and reference.
Seventh edition / Graham Sellers, Richard S. Wright, Jr., Nicholas Haemel.
pages cm
Includes bibliographical references and index.
ISBN 978-0-672-33747-5 (pbk. : alk. paper)ISBN 0-672-33747-9
(pbk. : alk. paper)
1. Computer graphics. 2. OpenGL. I. Sellers, Graham, author. II.
Haemel, Nicholas, author. III. Title.
T385.W728 2016
006.68dc23
2015014278

Copyright 2016 Pearson Education, Inc.

All rights reserved. Printed in the United States of America. This publication is protected by copyright, and permission must be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. To obtain permission to use material from this work, please submit a written request to Pearson Education, Inc., Permissions Department, 200 Old Tappan Road, Old Tappan, New Jersey 07675, or you may fax your request to (201) 236-3290.

ISBN-13: 978-0-672-33747-5
ISBN-10: 0-672-33747-9
Text printed in the United States on recycled paper at RR Donnelley in
Crawfordsville, Indiana.
First printing, July 2015

Editor-in-Chief
Mark L. Taub
Executive Editor
Laura Lewin
Managing Editor
John Fuller
Full-Service Production Manager
Julie B. Nahil
Copy Editor
Jill Hobbs
Indexer
Larry D. Sweazy
Proofreader
Anna Popick
Technical Reviewer
Matas Goldberg
Editorial Assistant
Olivia Basegio
Compositor
diacriTech

For you, the reader.
Graham Sellers

When OpenGL was young, the highest-end SGI systems like the Reality Engine 2 cost $80,000 and could render 200,000 textured triangles per second, or 3,333 triangles per frame at 60 Hz. The CPUs of that era were slower than today, to be sure, but at around 100 MHz, thats still 500 CPU cycles for each triangle. It was pretty easy to be graphics limited back then, and the API reflected thatthe only way to specify geometry was immediate mode! Well, there were also display lists for static geometry, which made being graphics-limited even easier.

OpenGL is not young anymore, the highest-end GPUs that it can run on cost around $1000, and they dont even list triangles per second in their basic product description anymore, but the number is north of 6 billion. Today these GPUs are in the middle of the single digit teraflops and several hundred gigabytes per second of bandwidth. CPUs have gotten faster, too: With 4 cores and around 3 GHz, they are shy of 200 gigaflops and have around 20 gigabytes per second of memory bandwidth. So where we had 500 CPU cycles for a triangle in the early days, we now have 0.5 cycles. Even if we could perfectly exploit all 4 cores, that would give us a paltry 2 CPU cycles for each triangle!

All that is to say that the growth in hardware graphics performance has outstripped conventional CPU performance growth by several orders of magnitude, and the consequences are pretty obvious today. Not only is the CPU frequently the limiting factor in graphics performance, we have an API that was designed against a different set of assumptions.

The good news with OpenGL is that it has evolved too. First it added vertex arrays so that a single draw command with fairly low CPU overhead gets amplified into a lot of GPU work. This helped for a while, but it wasnt enough. We added instancing to further increase the amount of work, but this was a somewhat limited form of work amplification, as we dont always want many instances of the same object in an organic, believable rendering.

Recognizing that these emerging limitations in the API had to be circumvented somehow, OpenGL designers began extending the interface to remove as much CPU-side overhead from the interface as possible. The bindless family of extensions allows the GPU to reference buffers and textures directly rather than going through expensive binding calls in the driver. Persistent maps allow the application to scribble on memory at the same time the GPU is referencing it. This sounds dangerousand it can be!but allowing the application to manage memory hazards relieves a tremendous burden from the driver and allows for far simpler, less general mechanisms to be employed. Sparse texture arrays allow applications to manage texture memory as well with similar, very low-overhead benefits. And finally multi-draw and multi-draw indirect added means the GPU can generate the very buffers that it sources for drawing, leaving the CPU a lot more available for other work.