1. Many of the figures from this book may be reproduced free of charge in scholarly articles, proceedings, and presentations, provided only that the following citation is clearly indicated: “Reproduced with the permission of the publisher from Computer Graphics: Principles and Practice, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley. Copyright 2014 by Pearson Education, Inc.” Reproduction for any use other than as stated above requires the written permission of Pearson Education, Inc. Reproduction of any figure that bears a copyright notice other than that of Pearson Education, Inc., requires the permission of that copyright holder.

2. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.1 The Cornell box, a carefully measured five-sided, painted plywood box with a light source at the top, is used as a standard test model for rendering algorithms. Here it’s rendered by photon mapping with 1 million photons.

3. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.2 A map contains less information and detail than a satellite photograph, but presents its information in a way that better communicates the salient elements to a human viewer. This is evidence that capturing many aspects of reality is not always the most effective way to model a scene. (Credit: © 2012 Google - Map data © 2012 Cnes/Spot Image, DigitalGlobe, GeoEye, MassGIS, Commonwealth of Massachusetts EOEA, New York GIS, USDA Farm Service Agency)

4. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.3 Subset of binary real numbers that can be represented with IEEE single- precision (32-bit) floating-point format. (Credit: Courtesy of Intel Corporation)

5. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.4 Distance between adjacent representable real numbers in 8.24-bit fixed point versus 32-bit floating point [AS06] over the range [10 −4, 1). Floating-point representation accuracy varies with magnitude. © 2006 ACM, Inc. Included here by permission.

6. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.5 The GL_R5G6B5 buffer format packs three normalized fixed-point values representing red, green, blue, and coverage values, each on [0, 1], into every 16-bit pixel. The red and blue channels each receive five bits. Because 16 is not evenly divisible by three, the “extra” bit is (mostly arbitrarily) assigned to the green channel.

7. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.6 The GL_RGBA8 buffer format packs three 8-bit normalized fixed-point values representing red, green, blue, and coverage values, each on [0, 1], into every 32-bit pixel. This format allows efficient, word-aligned access to an entire pixel for a memory system with 32-bit words. A 64-bit system might fetch two pixels at once and mask off the unneeded bits—although if processing multiple pixels of an image in parallel, both pixels likely need to be read anyway.

8. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.7 A real “stencil” is a piece of paper with a shape cut out of it. The stencil is placed against a surface and then painted over. When the stencil is removed, the surface is only painted where the holes were. A computer graphics stencil is a buffer of data that provides similar functionality.

9. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.8 The GL_DEPTH24 STENCIL8 buffer format encodes a 24-bit normalized fixed point “depth” value with eight stencil bits used for arbitrary masking operations.

10. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.9 The visible spectrum is part of the full electromagnetic spectrum. The color of light that we perceive from an electromagnetic wave is determined by its frequency. The relationship between frequency and wavelength is determined by the medium through which the wave is propagating. (Courtesy of Leonard McMillan)

11. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.10 The darkening of this photograph near the edges is called vignetting. (Credit: Swanson Tennis Center at Gustavus Adolphus College by Joe Lencioni, shiftingpixel.com)

12. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.11 The rainbowlike edges on the objects in this photograph are caused by chromatic aberration in the camera’s lens. Different frequencies of light refract at different angles, so the resultant colors shift in the image plane. High-quality cameras use multiple lenses to compensate for this effect. (Credit: Corepics VOF/Shutterstock)

13. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.12 The streaks from the sun and apparently translucent-colored polygons and circles along a line through the sun in this photograph are a lens flare created by the intense light reflecting within the multiple lenses of the camera objective. Light from all parts of the scene makes these reflections, but most are so dim compared to the sun that their impact on the image is immeasurable. (Credit: Spiber/Shutterstock)

14. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.13 A triangle list, also known as a triangle soup, contains 3n indices. List elements 3t, 3t + 1, and 3t + 2 are the ordered indices of triangle t.

15. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.14 A triangle strip contains n + 2 indices. The ordered indices of triangle t are given as follows. For even t, use list elements t, t + 2, t + 1. For odd t, use list elements t, t + 1, t + 2.

16. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.15 A triangle soup pentagon on the left, and the more efficient triangle fan model on the right. A triangle fan contains n + 2 indices. List elements 0, t + 1, t + 2 are the ordered indices of triangle t (with indices taken mod n + 2).

17. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.16 Blobby models, each defined by the isocontour of a sum of 3D Gaussian density functions [Bli82a]. (Credit: Courtesy of James Blinn © 1982 ACM, Inc. Reprinted by permission.)

18. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.17 Top: A video-game character from Team Fortress 2 rendered in real time using Approximate Catmull Clark subdivision surfaces. Bottom: The edges of the subdivision cage (projected onto the limit surface) in black, with special crease edges highlighted in bright green. (Credit: top: © Valve, all rights reserved, bottom: Courtesy of Denis Kovacs; © 2010 ACM, Inc. Reprinted by permission.)

19. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.18 Left: The water surface heightfield in CryEngine2. Right: Real-time rendering of the dynamic heightfield [Mit07]. (Credit: Courtesy of Tiago Sousa, © Crytek)

20. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.19 (a) A point set, with attached surface properties. (b) The gaps between points when rendered at this resolution. (c) The surface defined by splatting interpolation of the original points [PZvBG00]. (Credit: courtesy of Hanspeter Pfister, An Wang Professor of Computer Science, © 2000 ACM, Inc. Reprinted by permission.)

21. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.20 Example of a billboard cloud: (a) original model (5138 polygons), (b) false-color rendering using one color per billboard to show the faces that were grouped on each billboard, (c) view of the (automatically generated) 32 textured billboards, and (d) the billboards side-by-side. [DDSD03]. (Credit: Courtesy of Xavier Décoret, © 2003 ACM, Inc. Reprinted by permission.)

22. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.21 The game Minecraft models the entire world with 1m 3 voxels, enabling efficient, real-time illumination, simulation, and rendering for fully dynamic Earth-scale worlds.

23. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.22 Voxel data created by high-resolution surface displacement, with local shadowing precomputed and stored in the voxel grid. The resolution is approximately 5 mm throughout the entire building, including outer walls that are not visible from the inside. The total size of the data in GPU memory is 2.7 GB. Laine and Karras’s ray caster was able to cast about 61 million rays per second when rendering this scene; in other words, to render 1M pixels at 60 fps by ray tracing in 2010 [LK10]. (Credit: Courtesy of Samuli Laine and Tero Karras, © 2010 ACM, Inc. Reprinted by permission.)

24. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.23 Top: The flat, discrete nature of this cloud particle system’s rendering billboards is revealed where it intersects the terrain mesh. Bottom: Adjusting the pixel shader to use the “soft particle” technique that fades out the billboard’s contribution with proximity to scene geometry conceals this artifact. (Credit: Courtesy of Tristan Lorach, NVIDIA)

25. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.24 Box and ellipsoid fog volumes rendered by intersecting the view ray with an analytic volume inside a pixel shader. (Credit: Courtesy of Carsten Wenzel, © Crytek)

26. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.25 The vector ω i points toward the light source (represented by the star), so light propagates in direction −ω i. The light scatters at P and leaves in various directions ω o. The value f s (P, ω i, ω o ) measures the scattering.

27. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.26 Sphere rendered with a single light source, using a Phong BSDF with a white k g and orange k L. k g increases to the right and s increases upward. (Credit: From Creating Games: mechanics, content, and technology by McGuire, Morgan and Jenkins, Odest Chadwicke © 2009. Reproduced with permission of Taylor & Francis Group LLC - Books in the formats other book and textbook via Copyright Clearance Center)

28. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.27 An ideal blue vector star shape rasterized on a low-resolution pixel grid. The boxes of the grid are pixels. The circles represent samples at which we are computing coverage.

29. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.28 Light reflected at P.

30. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.29 The small, solid-angle ΔΩ and a corresponding small region ΔA on the luminaire’s surface.

31. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.30 Parameterization of a square area light on the ceiling.

32. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.31 Points and directions in point-light equations.

33. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.32 A theatre light with square “barn doors” (left), and a spot light with a round iris, matching our model. (Credit: top: Jim Barber/Shutterstock, bottom: Matusciac Alexandru/Shutterstock)

34. From Computer Graphics, Third Edition, by John F. Hughes, Andries van Dam, Morgan McGuire, David F. Sklar, James D. Foley, Steven K. Feiner, and Kurt Akeley (ISBN-13: 978-0-321-39952-6). Copyright © 2014 by Pearson Education, Inc. All rights reserved. Figure 14.33 A photograph of spiral patterns created by real gobos in spotlights (Credit: R. Gino Santa Maria/Shutterstock.com).