Advanced Global Illumination Second Edition

Advanced global lllumination Second edition Philip dure Kavita bala Philippe bekaert A K Peters, Ltd Wellesley, Massachusetts Editorial. Sales and Customer Service Office a PEters, Ltd 888 Worcester Street. Suite 230 Wellesley, MA 02482 www.akpeters Copyright c 2006 by a K Peters, Ltd All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in any form, electronic or mechani cal, including photocopying, rccording, or by any information storagc and retrieval systeIll, without written perimission Roil Che copyright owner Library of Congress Cataloging-in-Publication Data Dutre phi Advanced global illumination/Philip Dutre, Kavita Bala, Philippe Bekaert Includes bibliographical references and index ISBN13:9781-56881-307-3(alk. paper) IsBN10:1-56881-307-4(alk. paper) 1. Computer graphics. I. Bala, Kavita II. Bekaert, Philippe Ill. Title 1385.D892006 006.693dc22 2006044831 Printed in india 1009080706 10987654321 To my family. -Phil To Andrew. vivek, and ravi. -KB To Annelies, Lotte, and Fien . -Philippe Foreword here have been tremendous advances in the realism of computer-generated images over the last twenty years. This is the result of a great deal of research and is documented in thousands of technical papers. While this effort has resulted in many algorithmic and mathematical tools, it has also resulted in a vast and somewhat impenetrable literature. This literature has conflicting lerIns, sy Inbols, and oftel advocates approaches that are simply not practical. As a result, it is very difficult for new people to"get up to speed"and begin developing software to generate realistic images The most technical part of realistic image generation is dealing with "global lumination. The word"global" refers to the fact that the appearance of an object depends on the light it receives from all other objects. So in this sense, computing lighting even at a single point requires computation using the entire model of the scene. While this might seem like overkill the visual richness of an image created using a global illumination program is simply not possible with simpler local illumination programs Tllis book breaks down the barrier to entry and describes global illuini- nation concepts and algorithms from a modern viewpoint using consistent terms and symbols. While there are good books on specific global illumina tion topics, this is the first book to address global illumination techniques as a whole. The authors are ideal for such an ambitious project; they have a broad background in rendering and have done significant research in all of the major global illumination topics Most of the major theoretical advances in global illumination took place in the 1980s. These included the development of both radiosity and Monte Carlo ray tracing. In the 1990s, it became apparent that nonc of those algorithns were practical when applied in a straightforward manner. Inl that time, a more quiet revolution took place as techniques were developed to make global illumination practical for real-world models. The authors were key players in that revolution, and this book stresses techniques that havc bccn shown to work in the ficld. The approach of thc book has bccn fine-tuned in a course on global illumination taught by the authors at the annua.I SIGGRAPH conference, and this has resulted in a clean progression of ideas Since Advanced Global Illumination was published, it has become my default reference for points related to advanced rendering. I also recom- mend it to new students at my university who need to absorb twenty years of rendering research without wading through hundreds of dense papers that often have conflicting terminology or, worse, advance concepts that have since been discredited. Rendering images with realistic illumination cffects is vcry rewarding, and it is not hard once the basic concepts are clearly understood. This book describes all of those concepts, and it is a passport to making beautiful and realistic images. enjoy May 2006 Table of contents reface Preface to the second edition XV 1 Introduction 1.1 What Is Realistic Image Synthesis? 1.2 Structure of this b口uk 10 1.3 How to use this book 12 2 The Physics of Light Transport 15 2.1 Brief history 15 2.2 Models of light 17 2.3 Radiometry 19 2.4 Light Emission 2.5 Interaction of Light with Surfaces 31 2.6 Rendering equati 2.7 Importance 44 2. 8 The Measurement Equation 2.9 Summ 4 2.exErcises 45 弓 Monte carlo methods 47 3.1 Brief History 47 3.2 Why Are Mante Carlo Techniques Useful? 4 3.3 Review of Probability Theory 3.4 Monte Carlo Integration 54 3.5 Sampling Random Variables 63