Introduction to Computer Graphics Overview What is Computer Graphics by gregorio11

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									                     INSTITUTIONEN FÖR
                       SYSTEMTEKNIK
                            LULEÅ TEKNISKA UNIVERSITET




             Introduction to Computer Graphics

                         David Carr
              Fundamentals of Computer Graphics
                        Spring 2004
                         Based on Slides by E. Angel




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                             Overview


• What is Computer Graphics?
• Historical perspective




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                       SMD159, Introduction to Computer
                                  Graphics                     2   L




                     INSTITUTIONEN FÖR
                       SYSTEMTEKNIK
                            LULEÅ TEKNISKA UNIVERSITET




                What is Computer Graphics?




 Jan-15-04         SMD159, Introduction to Computer Graphics   3   L



                                                                       1
                        Computer Graphics

• Computer graphics deals with all aspects of creating
  images with a computer
      - Hardware
      - Software
      - Applications
• We will study:
      - Software and algorithms to create images
      - Construction of applications
• Use of packages to create images is “graphics on a
  computer”

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                                    Example

• Where did this image come from?




• What hardware/software did we need to produce it?

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                        Preliminary Answer

• Application: The object is an artist’s rendition of the
  sun for an animation to be shown in a planetarium.
• Software: Maya for modeling and rendering
      - Maya is built on top of OpenGL
• Hardware: PC with graphics cards for modeling and
  rendering




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                                                                     2
                        Basic Graphics System




                                                                     Output device

        Input devices
                           Image formed in the frame buffer


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                                         CRT




• Can be used either as:
      - A line-drawing device (calligraphic or vector mode)
      - To display the contents of a frame buffer (raster mode)

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                           INSTITUTIONEN FÖR
                             SYSTEMTEKNIK
                                  LULEÅ TEKNISKA UNIVERSITET




                          Historical Perspective




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                                                                                             3
                    Computer Graphics: 1950-1960

• Computer graphics goes back to the earliest days of
  computing
      - Strip charts
      - Pen plotters
      - Simple displays using A/D converters to go from computer to
        calligraphic CRT
• Cost of refresh for CRT too high
      - Computers slow, expensive, unreliable



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                    Computer Graphics: 1960-1970

•    Wireframe graphics
•    Project Sketchpad
•    Display processors
•    Storage tube




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                         Project Sketchpad

• Ivan Sutherland’s Ph.D. thesis at MIT
      - Recognized the potential of man-machine interaction
      - Loop
          + Display something
          + User moves light pen
          + Computer generates new display
      - Sutherland also created many of the now common algorithms
        for computer graphics




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                         Display Processor (DPU)

• A special purpose computer to refresh display that
  replaces the CPU




• Graphics stored in display list (display file) on the DPU
• Host compiles display list and sends to DPU



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                        Direct View Storage Tube

• Created by Tektronix
      - Did not require constant refresh
      - Standard interface to computers
         + Allowed for standard software
         + Plot3D in Fortran
      - Relatively inexpensive
         + Opened door to use of computer graphics for CAD
           community




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                   Computer Graphics: 1970-1980

• Raster Graphics
• Beginning of graphics standards
      - IFIPS
          + GKS: European effort
                • Becomes ISO 2D standard
            + Core: North American effort
                • 3D but fails to become ISO standard
• Workstations and PCs



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                                                                           5
                               Raster Graphics

• Image produced as an array (the raster) of picture
  elements (pixels) in the frame buffer




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                               Raster Graphics

• Allow us to go from lines and wireframes to filled
  polygons




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                          PCs and Workstations

• Although we no longer make the distinction
      - Workstations and PCs historically they evolved from different roots
      - Workstations came from the shrinking size and cost of minicomputers
      - PCs came from the increasing power of microprocessors
• Early workstations characterized by
      - Networked connection: client-server
      - High-level of interactivity
• Early PCs
      - Included the frame buffer as part of user memory
      - Often used TVs as displays



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                     Computer Graphics: 1980-1990

Realism comes to computer graphics




   smooth shading                 environmental               bump mapping
                                    mapping

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                    Computer Graphics: 1980-1990

• Special purpose hardware
      - Silicon Graphics geometry engine
         + VLSI implementation of graphics pipeline
• Industry-based standards
      - PHIGS
      - RenderMan
• Networked graphics: X Window System
• Human-Computer Interface (HCI)


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                     Computer Graphics: 1990-2000

• OpenGL API
• Completely computer-generated feature-length movies
  (Toy Story) are successful
• New hardware capabilities
      - Texture mapping
      - Blending
      - Accumulation, stencil buffer




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                   Computer Graphics: 2000-

• Photorealism
• Graphics cards for PCs dominate market
      - Nvidia, ATI, 3DLabs
• Game boxes and game players determine direction of
  market
• Computer graphics routine in movie industry: Maya,
  Lightwave



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                                Questions




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