Introduction to COMPUTER GRAPHICS A Practical Learning Approach FABIO GANOVELLI • MASSIMILIANO CORSINI SUMANTA PATTANAIK • MARCO DI BENEDETTO Fabio Ganovelli Massimiliano Corsini Sumanta Pattanaik Marco Di Benedetto Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business A CHAPMAN & HALL BOOK CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2015 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S Government works Version Date: 20140714 International Standard Book Number-13: 978-1-4822-3633-0 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use The authors and publishers have 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of users For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com To Reni F Ganovelli To my grandmother, my parents and my wife M Corsini To my parents S Pattanaik To my family M Di Benedetto Contents List of Figures xvii List of Listings xxvii Preface xxxi What Computer Graphics Is 1.1 Application Domains and Areas of Computer Graphics 1.1.1 Application Domains 1.1.2 Areas of Computer Graphics 1.2 Color and Images 1.2.1 The Human Visual System (HVS) 1.2.2 Color Space 1.2.2.1 CIE XYZ 1.2.2.2 Device-Dependent and Device-Independent Color Space 1.2.2.3 HSL and HSV 1.2.2.4 CIELab 1.2.3 Illuminant 1.2.4 Gamma 1.2.5 Image Representation 1.2.5.1 Vector Images 1.2.5.2 Raster Images 1.3 Algorithms to Create a Raster Image from a 3D Scene 1.3.1 Ray Tracing 1.3.2 Rasterization-Based Pipeline 1.3.3 Ray Tracing vs Rasterization-Based Pipeline 1.3.3.1 Ray Tracing Is Better 1.3.3.2 Rasterization Is Better 10 11 12 13 13 13 14 17 17 20 21 21 22 The 2.1 2.2 2.3 2.4 23 23 25 28 40 First Steps The Application Programming Interface The WebGL Rasterization-Based Pipeline Programming the Rendering Pipeline: Your First Rendering WebGL Supporting Libraries 1 2 5 vii viii Contents 2.5 Meet NVMC 2.5.1 The Framework 2.5.2 The Class NVMC to Represent the World 2.5.3 A Very Basic Client 2.5.4 Code Organization 40 41 42 42 48 How a 3D Model Is Represented 3.1 Introduction 3.1.1 Digitalization of the Real World 3.1.2 Modeling 3.1.3 Procedural Modeling 3.1.4 Simulation 3.2 Polygon Meshes 3.2.1 Fans and Strips 3.2.2 Manifoldness 3.2.3 Orientation 3.2.4 Advantages and Disadvantages 3.3 Implicit Surfaces 3.3.1 Advantages and Disadvantages 3.4 Parametric Surfaces 3.4.1 Parametric Curve 3.4.2 B´ezier Curves 3.4.2.1 Cubic B´ezier Curve 3.4.3 B-Spline Curves 3.4.4 From Parametric Curves to Parametric Surfaces 3.4.5 B´ezier Patches 3.4.6 NURBS Surfaces 3.4.7 Advantages and Disadvantages 3.5 Voxels 3.5.1 Rendering Voxels 3.5.2 Advantages and Disadvantages 3.6 Constructive Solid Geometry (CSG) 3.6.1 Advantages and Disadvantages 3.7 Subdivision Surfaces 3.7.1 Chaikin’s Algorithm 3.7.2 The 4-Point Algorithm 3.7.3 Subdivision Methods for Surfaces 3.7.4 Classification 3.7.4.1 Triangular or Quadrilateral 3.7.4.2 Primal or Dual 3.7.4.3 Approximation vs Interpolation 3.7.4.4 Smoothness 3.7.5 Subdivision Schemes 3.7.5.1 Loop Scheme 3.7.5.2 Modified Butterfly Scheme 51 51 52 52 53 53 53 54 54 55 56 57 58 58 59 59 61 63 64 66 67 67 68 69 70 70 71 71 71 72 73 73 73 73 74 75 75 76 76 ... identifying faces, refocusing images, automatically creating panoramas, capturing Introduction to Computer Graphics: A Practical Learning Approach images in high dynamic range, estimating the depth... you go to the cinema you may see your latest movie partly or entirely generated through a computer and a bunch of CG algorithms, Introduction to Computer Graphics: A Practical Learning Approach. .. Computer Graphics: A Practical Learning Approach FIGURE 1.9: (Left) Original image with opaque background (Middle) Background color made transparent by setting alpha to zero (transparency is indicated