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									           Introduction to Computer Graphics


                         Pradondet Nilagupta
                    Dept. of Computer Engineering
                         Kasetsart University


204481 Foundation of Computer Graphics   October 1, 2012   1
         Lecture Outline

        Course Information: Format, Resources
        Overview
             Topics covered
             What is computer graphics?
             Applications




204481 Foundation of Computer Graphics   October 1, 2012   2
         Course Info and Administrative

     Instructor: Pradondet Nilagupta
         E-mail: pom@ku.ac.th
         Phone: 9428555 ext. 1415 (office)
         Office hours: after class; 1-2pm Monday or by
          appointment

     Web Page
         Course Homepage:
          http://www.cpe.ku.ac.th/~pom/courses/204481/
          204481.html
         Course Syllabus:
          http://www.cpe.ku.ac.th/~pom/courses/204481/
          syllabus.html
204481 Foundation of Computer Graphics   October 1, 2012   3
         Course Overview (1/2)

        Graphics Systems and
         Techniques
             2-D, 3-D models: surfaces,
              visible surface identification,
              illumination
             Photorealistic rendering :
              shading models, ray tracing,
              radiosity
        Operations
             Surface modeling, mapping
             Pipelines for display,
              transformation, illumination

204481 Foundation of Computer Graphics          October 1, 2012   4
         Course Overview (2/2)

        Mathematical Review
             Review of mathematical foundations of CG:
              analytic geometry, linear algebra
             Line and polygon rendering
             Matrix transformations




204481 Foundation of Computer Graphics   October 1, 2012   5
         Relevant Disciplines
                                        Rendering Hardware                 CAD
                                                                                             Immersive Training
                                            VR Systems                  CAE / CASE
   Analytic Geometry                  Portable/Embedded CG               CAM
                                                                                             Tutoring Interfaces

   Art and Graphic Design
   Cognitive Science             Color/Optical Models
                                    CG/Vision Duality
   Computer Engineering            Interface Design

   Engineering Design        Layout
                            CG Design
   Education              Visualization
   Film
                      Parametric Equations
   Human Factors            Conics                                    Computer
                       Polygon Rendering
   Linear Algebra                                                     Graphics
   Numerical Analysis                                                   (CG)
           Surface Modeling
       Physically-Based Modeling
         Stat/Info Visualization


            Transformations
      Change of Coordinate Systems
                                                User Modeling                          Animation
                                           Ergonomic Interfaces, I/O                 Large-Scale CG

204481 Foundation of Computer Graphics            October 1, 2012                                                  6
             What is Computer Graphics?




204481 Foundation of Computer Graphics   October 1, 2012   7
         This is not Computer Graphics
                      18%

              9%

                                          1
                                          2
                                          3
                                          4
                                    46%
            27%




   [ 29:akin@sgi.com ] Re: Future development of
    PEX/PHIGS]
   [ 9:bthompso@reed] What is a good book for
    Digital Image Processing]
   [ 15:csp48@seq1.ke] Help! ASCII picture
    needed…
   [ 14:rcj2@cbnewsd.] Re: 3D igitizers… again
   [240:raj@ms.uky.ed] Call For Papers -- ACM
    Multimedia '93

204481 Foundation of Computer Graphics        October 1, 2012   8
         What is Computer Graphics ?

        Computer graphics is commonly
         understood to mean the creation,
         storage and manipulation of models
         and images. (Andries van Dam)
        Computer graphic is concerned with
             all aspects of producing pictures or
              images using a computer.
             the pictorial synthesis or real or
              imaginary objects from their computer
              based model


204481 Foundation of Computer Graphics   October 1, 2012   9
         Computer Graphics

        Computer Graphics
             Synthesis of graphical images
             Visualization :
                  creating an image from an abstract, symbolic
                   description.
             Generation of Synthesis Image
                  using graphical primitives
                  data from real world phenomena



204481 Foundation of Computer Graphics   October 1, 2012          10
         Image Processing

        Image Processing
             the transformation of an existing image into a
              more desirable or useful image.
                  image enhancement, pattern detection




                   The following images represent how noise affects images

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         Image Analysis

        Image Analysis (Computer Vision)
              extracting symbolic information from the image.




         Computer Graphics               Data      => Picture
         Image Processing                Picture => Picture
         Image Analysis                  Picture => Data
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         What is Interactive Computer Graphics?

        User controls contents, structure, and
         appearance of objects and their displayed images
         via rapid visual feedback
        Basic components of an interactive graphics
         system
             input (e.g., mouse, tablet and stylus, force feedback
              device,scanner…)
             processing (and storage)
             display/output (e.g., screen, paper-based printer, video
              recorder…)

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         Why Computer Graphics? (1/5)

        Humans communicate well with images
             1/3 of your brain is devoted to visual
              processing
        A picture is worth a few hundred megabytes




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         Why Computer Graphics? (2/5)

        Developing Computational Capability
             Rendering: synthesizing realistic-looking,
              useful, or interesting images
             Animation: creating visual impression of motion
             Image processing: analyzing, transforming,
              displaying images efficiently




204481 Foundation of Computer Graphics   October 1, 2012        15
         Why Computer Graphics? (3/5)

        Better Understanding of Data, Objects,
         Processes through Visualization
             Visual summarization, description,
              manipulation
             Virtual environments (VR), visual monitoring,
              interactivity
             Human-computer intelligent interaction (HCII):
              training, tutoring, analysis, control systems

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         Why Computer Graphics? (4/5)

        Time is Right
             Recent progress in algorithms and theory
             Rapidly emergence of new I/O (display and data
              acquisition) technologies
             Available computational power, improving price-
              performance-ratio of hardware
             Growth and interest of graphics industries (e.g.,
              information visualization, entertainment CAD)



204481 Foundation of Computer Graphics   October 1, 2012          17
         Why Computer Graphics? (5/5)

        advances in the last decade due mostly to the
         microchip
        software advances, especially in object-oriented
         programming and real-time rendering algorithms
        Hardware advances continue to benefit graphics:
             faster inexpensive microprocessors and dedicated
              graphics chips
             screen technology: High-definition television (HDTV),
              colour LCD
             virtual reality interfaces (corneal implants?)


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         Image Synthesis Pipeline
  Graphics
  Database
   Editing




                                    Front-End

    Graphics
    Database
                           (Geometry Processing)

                                                                          Back-End


                Display
               Traversal
                              Modeling
                           Transformation
                                                 Viewing
                                                Operation
                                                                      (Rasterization)




                                                                    • Visible-Surface
                                                                      Determination
                                                                    • Scan Conversion    Image
                                                                    • Shading /
                                                                      Illumination




204481 Foundation of Computer Graphics            October 1, 2012                                19
         A Brief History

        teletype printouts were first graphical output devices
         lightpens were an early input device CAD applications
         began in the 1960's plotters also a 60's development: high-
         resolution, but slow main bottlenecks of computer graphics
         back then
         cost of graphics hardware
         expense of computer resources
         batch systems weren't suitable
         for interactive graphics
         non-portability of hardware and
         software
         a new field: technology was
         primitive
204481 Foundation of Computer Graphics      October 1, 2012            20
       History of Computer Graphics (1/5)
      1950 MIT’s Whirlwind
       computer had computer
       generated CRTs mid
       1950s SAGE command
       and control
      1960s Ivan Sutherland’s
       thesis - Sketchpad
           introduced data
            structures and interactive
            techniques
                                  http://www.computer.org/history/development/1951.htm

204481 Foundation of Computer Graphics       October 1, 2012                             21
         History of Computer Graphics (2/5)

        1960s GM (general Motor)
             developed CAD (Computer Aided Design) and
              CAM
        1968 Tektronix storage tubes
        1970s Boeing CAD CAM




204481 Foundation of Computer Graphics   October 1, 2012   22
       History of Computer Graphics (3/5)

           Mid 1970s engineering workstations and
            personal computers emerged separately
           1980s new algorithms and techniques
                new standards
                ever more powerful system
                transition from specialized field
           1990s widespread use
                low cost, but powerful personal workstations
                networks
                essential part of systems
                now part of multimedia

204481 Foundation of Computer Graphics   October 1, 2012        23
         History of Computer Graphics (4/5)

     At first - progress was slow because
      cost of equipment was high (specially
       memory)
      significant computing resources needed

      difficulty in writing software ( harder than it
       looks)
      lack of standard and thus portability

      lack of software tools


204481 Foundation of Computer Graphics   October 1, 2012   24
         History of Computer Graphics (5/5)

     Now - previous use
      cost of equipment is low.

      Most computer have necessary
       computing resources for graphics
      established standards,
       implementations and tools
      still difficulty in writing software ( still
       harder than it looks)
204481 Foundation of Computer Graphics   October 1, 2012   25
         Some of Historical Picture (1/2)
                                             First truly interactive graphics
                                              system, Sketchpad, pioneered
                                              at MIT by Ivan Sutherland for
                                              his 1963 Ph.D. thesis.
                                              Sketchpad, A Man-Machine
                                              Graphical Communication
                                              System:
                                             Sketchpad in 1963. Note the
                                              use of a CRT monitor, light
                                              pen and function-key panel.




204481 Foundation of Computer Graphics   October 1, 2012                         26
         Some of Historical Picture (2/2)

                                     http://www.man.ac.uk/Science_Engineering/CHSTM/nahc.htm
         John VonNeuman




     http://ei.cs.vt.edu/~history/VonNeumann.html                 Mark I

204481 Foundation of Computer Graphics         October 1, 2012                                 27
         Applications of Computer Graphics

     Applications of Computer Graphics
      divided in 4 majors area

           Display of Information
           Design

           Simulation

           User Interface




204481 Foundation of Computer Graphics   October 1, 2012   28
         Display of Information

        Geographic
         information system
         (GIS)
        Computerized
         Tomography (CT)
        Magnetic resonance                   http://www.soest.hawaii.edu/soest/about.ftp.html

         imaging (MRI)
        Ultrasound
        positron-emission
         tomography (PET)
                                              http://www.queens.org/qmc/services/imaging/ct.htm

204481 Foundation of Computer Graphics   October 1, 2012                                          29
         Design

        Computer-Aided Design (CAD)
           Architecture
           Design of Mechanical part

           VLSI

           etc...




                             http://www.memagazine.org/contents/current/features/push/push.html


204481 Foundation of Computer Graphics         October 1, 2012                                    30
         Simulation

        Graphical flight simulator
             reduce training process
        Robotic simulation
                                                                     The Concorde Panel.
        TV, Movie, advertising industries
             generate photo realistic images
        Virtual Reality (VR)
             reduce risk of training
                surgery
                astronaut

                                                http://www.motionshop.com/pr/festocosimirlg.shtml

204481 Foundation of Computer Graphics   October 1, 2012                                            31
         User Interfaces

        Window system
           Window 2003
           X window

           MAC OS

        Graphical Network browsers
           Netscape
           Internet Explorer



204481 Foundation of Computer Graphics   October 1, 2012   32
         Areas of research in Graphics (1/2)

        mathematical modeling:
             interpolation, curve and surface fitting
             computational geometry: algorithmic
              applications in geometry
             study of light and optical phenomenon: colour,
              texture, shades
             modelling the characteristics of physical
              objects (bouncing Jello)


204481 Foundation of Computer Graphics   October 1, 2012       33
         Areas of research in Graphics (2/2)

        Software technology
             standardized graphics languages and libraries
             graphics tools and interfaces
             algorithm design
        Hardware
             specialized graphics chips, monitors, interface
              devices



204481 Foundation of Computer Graphics   October 1, 2012        34
         Graphics Applications

        Entertainment: Cinema
                                         Pixar: Geri’s Game




                                                                   Universal: Jurassic Park




                                          Antz




                                                                    A bug’s Life
204481 Foundation of Computer Graphics           October 1, 2012                              35
         Graphics Applications (1/4)

         Entertainment: Games


                                                                    Aki Ross : Final Fantasy




         Star Wars Jedi Outcast: Jedi Knight II




                                                                             Quake III
204481 Foundation of Computer Graphics            October 1, 2012                              36
         Graphics Applications (2/4)

        Medical Visualization




                                                                      The Visible Human Project
      http://www.ercim.org/publication/Ercim_News/enw44/koenig.html

204481 Foundation of Computer Graphics       October 1, 2012                                      37
         Graphics Applications (3/4)

        Computer Aided Design (CAD)




204481 Foundation of Computer Graphics   October 1, 2012   38
         Graphics Applications (4/4)

        Scientific Visualization




204481 Foundation of Computer Graphics   October 1, 2012   39
     Hypermedia User Interfaces (1/2)
                                                     NCSA D2K:
                                                        http://chili.ncsa.uiuc.edu
                                                     Visual programming system for
                                                        high-performance knowledge
                                                        discovery in databases (KDD)




        Hypermedia
             Database format (similar to hypertext) that provides display-based
              access to (internetworked) multimedia (text, image, audio, video,
              etc.) documents
             Chimera: http://www.ics.uci.edu/pub/chimera/


204481 Foundation of Computer Graphics     October 1, 2012                             40
         Hypermedia User Interfaces (2/2)

        Virtual Environments
             Immersion: interactive
              training, tutoring systems
             Entertainment hypermedia
        Visualization and Computer-
         Aided Design and Engineering
         (CAD/CAE)
             Visualization: scientific,
              data/information, statistics
             User interfaces for
              CAD/CAE/CAM/CASE:
              http://www.isii.com
                                                          http://www.psl.cs.columbia.edu/chime/


204481 Foundation of Computer Graphics       October 1, 2012                                      41
    Curve and Surface Modeling
            1                      http://www.geocities.com/SiliconValley/Lakes/2057/nurbs.html
                    2
                                               3
                                                                       4



                                                                                                  5




        8                           7




                                                                          6




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       Photorealistic Illumination Models
                                         http://www.pixar.com




http://www.ktx.com/3dsmaxr3/                                       http://www.aliaswavefront.com




204481 Foundation of Computer Graphics           October 1, 2012                                   43
        Fractal Systems




                            http://sprott.physics.wisc.edu/fractals.htm

204481 Foundation of Computer Graphics         October 1, 2012            44
        Information Visualization




                Visible Decisions SeeIT          (http://www.vdi.com)
204481 Foundation of Computer Graphics    October 1, 2012               45
    Interesting Industrial Applications
                                                           6500 news stories
                                                           from the WWW
                                                           in 1997




                                                               Cartia ThemeScapes – http://www.cartia.com

                                                       Hypermedia and Statistical Visualization

                                                                                      Destroyed
                                                               Normal
                                                                                     Extinguished
                                                               Ignited
                                                                                      Fire Alarm
                                                              Engulfed
                                                                                       Flooding


                                                          Virtual Environments for
              DC-ARM – http://www-kbs.ai.uiuc.edu            Immersive Training
204481 Foundation of Computer Graphics              October 1, 2012                                         46
          Overview of Programmer’s Model (1/2)
        Pixel - smallest addressable unit of display
        Hardware (I/O)
             output display device (normally raster scan)
             on the order of a million pixels displayed
             image stored in memory by pixel
              (how much memory?)
                  video controller
                  scans the memory periodically (30-72 times a second)
                   produces video signal to drive a video monitor (or flat screen
                   display)
                  input devices - keyboard, mouse (track ball), tablet, voice etc.



204481 Foundation of Computer Graphics       October 1, 2012                          47
         Overview of Programmer’s Model (2/2)

     Software
      application data

      application program

      graphics interface

      operating system




204481 Foundation of Computer Graphics   October 1, 2012   48
         Graphical System And Standard (1/5)

        Graphical Systems
             High level language interface to graphical
              devices.
             Intended for development of portable code.
             Standard graphical systems include
                  CORE,
                  Graphical Kernel System (GKS), GKS+
                  Programmers Hierarchical Interactive Graphics
                   System (PHIGS), PHIGS+
                  OpenGL, DirectX, Quickdraw 3D, VRML,
                   Open Inventor, X-Windows.

204481 Foundation of Computer Graphics   October 1, 2012           49
         Graphical System And Standard (2/5)

        Requirements of Graphical Systems
             Portability
                  Device Independence
                   Concept of a logical device.
                  Language Independence
                   Language Bindings for graphical systems.
                  Computer Independence
                   Trade-off between standard hardware and high
                   performance hardware.
             Programmer Independence
             Flexibility - In conflict with portability.

204481 Foundation of Computer Graphics   October 1, 2012          50
         Graphical System And Standard (3/5)

        Graphical Kernel System (GKS)
          Workstation
                  GKS has concept of a workstation.
             Device Normalisation
                  World Coordinates, Window in World Coordinates
                  Clipping to the window
                  Normalised Device Coordinates [0,1]x[0,1]
                  Normalisation Transformation
                  Viewports in normalised device coordinates



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         Graphical System And Standard (4/5)

             Output Functions
                  Line-Drawing Primitives
                  Area-filling primitives
                  Text Output
             Input Functions
                  Logical input types : Locator, Valuator, Choice,
                   String, Pick, Stroke.




204481 Foundation of Computer Graphics   October 1, 2012              52
         Graphical System And Standard (5/5)

             Input Modes
                  Request mode: waits for a request for an event.
                  Sample mode: continually samples value of input
                   device.
                  Event mode: unsolicited input stored on a stack,
                   made available for processing in FIFO order.
                  Mixed mode.




204481 Foundation of Computer Graphics   October 1, 2012              53
         Professional Societies

     ACM SIGGRAPH
     - Association for Computing
         Machinery Special Interest
         Group in Graphics
     IEEE
      - The Institute of Electrical and
         Electronics Engineers,
         Technical Committee on
         Computer Graphics

204481 Foundation of Computer Graphics   October 1, 2012   54
          Software Portability and graphics
          standards
     STANDARD
       ORGANIZATION
      ANSI = American National
       Standard Institute (private,
       non government)
      ISO = International
       Standards
       Organization(voluntary,
       non treaty)
      ANSI is a member of ISO

204481 Foundation of Computer Graphics   October 1, 2012   55
         History: graphics libraries

        initially, low-level device-dependent
         packages were the norm
        movement towards high-level device-
         independent packages, in order to promote
         application program portability
        requires standardization:



204481 Foundation of Computer Graphics   October 1, 2012   56
         Official Standards

        1977 and 1979 - 3D SIGGRAPH CORE (ACM
         SIGGRAPH)
        3D Core Graphics System ("Core") dev'd in late
         70's as unofficial std
        GKS (Graphical Kernel System, 1985): official 2D
         standard built from Core
        GKS-3D (1988): 3d objects ANSI X3.124-1985
        PHIGS (Programmer's Hierarchical Interactive
         Graphics System, 1988) 3D nested objects
        PHIGS+ (1988): rendering enhancements

204481 Foundation of Computer Graphics   October 1, 2012    57
         Emerging Standards in APIs

        OpenGL (developed by Silicon Graphics)
             open standard
             available on all platforms
             intended for professional-level graphics like
              CAD
        Direct3D
             developed by Microsoft
             Windows only
             intended for games

204481 Foundation of Computer Graphics   October 1, 2012      58
         Some Notable Systems
        Tektronix commands in BASIC (mid-1970s)
        HP commands (Hewlett Packard)
        Microsoft BASIC (for PCs) graphics
         commands (early 1980s)
        QuickDraw (Apple Macintosh)
        X (MIT)
        OpenGL (Silicon Graphics)
        SRGP (Simple Raster Graphics Package)
        SPHIGS (Simple PHIGS)
        MS Windows
        Java AWT

204481 Foundation of Computer Graphics   October 1, 2012   59
          Good graphics requires ? (1/3)
        ability to control every dot (pixel) of display
        ability to control primitive shapes on the
         screen
        models to deal with images as a whole
        use of color, lighting, and shading
        construction of "languages" or "packages"
         to extend languages
        knowledge of hardware
        systems work

204481 Foundation of Computer Graphics   October 1, 2012   60
          Good Graphics requires ? (2/3)

         mathematical transformations and
          representations
         transmission of pictures and commands to
          make pictures
         ability to store lots of information
         high performance computers
         algorithms such as visible surface
          algorithms

204481 Foundation of Computer Graphics   October 1, 2012   61
          Good Graphics requires ? (3/3)

        understanding and manipulation of
         data structures
        good software engineering principles
        human factors engineering
        some feeling for artistic principles
        lots of effort - harder than it looks


204481 Foundation of Computer Graphics   October 1, 2012   62
         Lecture Topics

     Introduction                       Visible Surface
     Mathematical                       Determination
      Foundation                               Algorithm efficiency
     Coordinate Systems                       Z-buffer algorithm
     Introduction to                          Scan line algorithms
      Graphics in 2D
                                               Visible-surface Ray Tracing
     Windows and Clipping
                                               Other algorithms
     Introduction to
      Graphics in 3D                      Color Models
     Viewing in 3D                       Illumination and Shading

204481 Foundation of Computer Graphics   October 1, 2012                      63
         Mathematical foundation

        Mathematical appears throughout 3D graphics
     Example:
        Object surfaces can be represented as polygons
         whose vertex position are specified by vectors
        Rendering requires testing whether vertices lie in
         front of or behind various planes.
        The test involves a dot product with the plane’s
         normal vector.


204481 Foundation of Computer Graphics   October 1, 2012      64
         Geometric transformation

        Goal: specify object’s position and
         orientations in a 3D world
        Use Linear transformations that rotate
         and translate objects’ vertices.
        Apply these transformations in matrix
         form


204481 Foundation of Computer Graphics   October 1, 2012   65
         Viewing

        Goal: map the visible part of a 3D
         world to a 2 D image
        Use camera-like parameters to define
         a 3D view volume
        Project the view voulme onto a 2D
         image plane
        Map viewport on the image plane to
         the screen

204481 Foundation of Computer Graphics   October 1, 2012   66
         OpenGL

        OpenGL is strictly defined as “a software
         interface to graphics hardware”.
        It is a 3D graphics and modeling library
        variety purposes, CAD engineering,
         architectural applications, computer-
         generated dianosaurs in blockbuster
         movies
        Developed by SGI

204481 Foundation of Computer Graphics   October 1, 2012   67
         Clipping


        Goal: cut off the part of objects outside
         the view volume to avoid rendering
         them




204481 Foundation of Computer Graphics   October 1, 2012   68
         Scan Conversion

        Goal: convert a project, clipped object
         into pixels on raster lines.
        Use efficient incremental methods




204481 Foundation of Computer Graphics   October 1, 2012   69
         Antialiasing

        Raster displays produce blocky
         aliasing artifacts
        Antialiasing techniques reduces the
         problem by applying the theory of
         sampling and signal processing




204481 Foundation of Computer Graphics   October 1, 2012   70
         Color

        Various color spaces provide ways to
         specify colors in term of components:
        red, green, blue
        hue, saturation, value
        Different output devices display
         different subsets of the perceptible
         colors

204481 Foundation of Computer Graphics   October 1, 2012   71
         Hidden Surface Removal

           When several overlapping polygons are
            drawn on the screen, which one is on
            top?
                                         Which is
                                         right?




204481 Foundation of Computer Graphics        October 1, 2012   72
         Z-buffering

        A fast hardware solution is         This pixel is
                                             drawn on
         the Z-buffer
                                             screen
        The “depth” of each pixel
         relative to the screen is                             Screen
         calculated and saved in a                                      Polygons
         buffer
        The pixel with the smallest
         depth is the one that is
         displayed
        The other pixels are on                           Z
         surfaces that are hidden


204481 Foundation of Computer Graphics   October 1, 2012                           73
          Lighting Models and Shading

    For visual realism, lighting                     Ambient lighting:
     models have been developed
     to illuminate the surfaces of
     solid models
    These models incorporate
                                                           incident       reflected light
         ambient lighting and illumination                light
         diffuse reflection of directional
          lighting
         specular reflection of directional                              reflected light
                                                           incident
          lighting                                         light




204481 Foundation of Computer Graphics   October 1, 2012                                    74
         Ray Tracing
                                                                 Light Source

                                                                 Shadow Ray
           Eye
                                                                            Object
                                            Eye Ray



                                         Shadow Ray
                                                          Object
                                               Light Source
        Ray tracing traces a ray
         of light from the eye to a
         light source
        Ray tracing realistically
         renders scenes with
         shiny and transparent
         objects
204481 Foundation of Computer Graphics         October 1, 2012                       75
         Radiosity

        Diffuse illumination
         results from the
         absorption and reflection
         of diffuse light from
         many objects in the
         scene
        Radiosity uses thermal
         models of emission and
         reflection of radiation to              Radiosity is very good at
         accurately calculate                    rendering architectural
                                                 interiors
         diffuse lighting

204481 Foundation of Computer Graphics   October 1, 2012                     76
         Texture Mapping

        For realism, photographic textures are
         “mapped” onto the surfaces of objects
        Example textures:                                      texture
                                                                mapping
             woodgrain
             concrete
             grass                                            reflections

             marble               shadows

        Texture mapping is very computationally
         intensive

204481 Foundation of Computer Graphics       October 1, 2012                 77
         Example of Shading




             Wireframe                                 Flat Shaded




          Smooth Shaded                                    Shadows

204481 Foundation of Computer Graphics   October 1, 2012             78

								
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