development of computer graphicsfarrell/cg01/lectures/cg02.pdfz random scan versus raster scan z...
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1/20/2000 CS 4/57101 Lecture 2 1
Development of Computer Graphics
z 1951y Whirlwind, Jay Forrester (MIT)y CRT displays
z mid 1950sy SAGE air defense systemy command & control CRT, light pens
z late 1950sy Computer Art, James Whitney Sr.y Visual Feedback loops
z 1962y Sketchpad, Ivan Sutherlandy data structures, light pen for drawing and choices
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Development of Computer Graphics
z Early display devices (mid-60s):z Vector, stroke, line drawing, calligraphic displaysz Architecture of Vector Display
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Development of Computer Graphics
z Architecture of a vector display - random scany vector generator converts digital coordinates to beam
deflections
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Development of Computer Graphics
z 1964y CAD and CAMy General Motors DAC, Itek Digitek for Lens Design
z 1964-1970sy Photorealism at University of Utahy Sutherland, Evans, Catmull, Blinn
z 1968y Evans & Sutherlandy commercial company - flight simulatorsy 3D vector pipeline, matrix multiplier, clipping
z 1969y First SIGGRAPH
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Development of Computer Graphics
z 1970y Pierre Bezier - Bezier curves
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Development of Computer Graphics
z 1971:y Gouraud Shading
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Development of Computer Graphics
z 1974-1977y Catmull - Z-buffery Bui-Toung Phong creates Phong Shading (Utah)y Martin Newell's teapot (Utah)y Computer graphics at NYIT - computer animationy Raster Graphics (Xerox PARC, Shoup)
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Development of Computer Graphics
z Architecture of a raster display
1/20/2000 CS 4/57101 Lecture 2 9
Development of Computer Graphics
z Architecture of a raster display - raster scany beams (3 beams) intensity set to reflect pixel intensityy scan speed: originally 30Hz now 60Hz
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Development of Computer Graphics
z Raster Scany need to store whole imagey 1024 x1024 x n - n bits per pixely mono 1 bit, color 8 (256 color), 24 (16 million)y 32 to 96 bits used (double buffering, z-buffering)y 1280x1024x24 needs only 3.75 MB video RAM
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Development of Computer Graphics
z Random Scan versus Raster Scany note ragged lines
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Development of Computer Graphics
z Random Scan versus Raster Scanz Raster advantages:
y low cost, superior fill ability, refresh rate independent ofcomplexity, 70Hz sufficient to avoid flicker
z Raster disadvantages:y discrete nature of pixel representation, need for scan conversion
in software or RIP chipsx real-time dynamics more demanding
y approximation of lines by sequence of pixelsx aliasing - jaggies or staircasingx manifestation of sampling error in signal processingx need for anti-aliasing
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Development of Computer Graphics
z 1976y Image and texture mapping
(Blinn)
z 1977y 3D Core Graphics System,y first “standard” for device
independent graphics packagey allowed portable graphics
programmingy ACM SIGGRAPH committee
including Foley, Van Dam,Feiner
y baseline specification - manyimplementations
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Development of Computer Graphics
z 1982y Clarke, Geometry Engine
x hardware support for transforms (matrix-vector multiplies),clipping (variant of Sutherland-Hodgman algorithm)
y IRIS - Integrated Raster Imaging System, SGIx high-end workstationx hardware acceleration of graphics pipeline
z 1982y TRON, Star Trek - Genesis Effect
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Development of Computer Graphics
z 1982y Ray Tracing, Turner Whitted
z 1983y VRAM, Video random access
memory, Texas Instrumentsx can read out all pixels in
one memory cycle
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Development of Computer Graphics
z 1983y Fractals
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Development of Computer Graphics
z 1985y Radiosity, Don Greenberg (Cornell)y GKS, Graphical Kernel System
x first ANSI standardx elaborated cleaned up version of CORE but only 2D
z 1986y Renderman
z 1988y GKS, Graphical Kernel System - 3D version
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Development of Computer Graphics
z 1988y PHIGS, PHIGS+y Programmer’s Hierarchical Interactive Graphics Systemy More complex than CORE
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PHIGS v GKS
z GKS allowed grouping of primitives into “segments”y no nesting of segements
z PHIGS allowed nested hierarchical grouping of 3Dprimitives into “structures”y all primitives subject to geometric transformationsy editable database of structuresy auto-update of screen when database altered
z PHIGS+y extension for pseudo-realistic rendering on raster devices
z PHIGS, PHIGS+ large packagesy run best with hardware support of transforamtions, clipping and
rendering
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Development of Computer Graphics
z 1993y OpenGL - Open Graphics Libraryy derived from SGI’s GL library
z 1993y Open Inventor, OO layer on OpenGL
z 1995y QuickDraw 3D, Apple
z 1995y Direct3D, Microsoft, game playing API
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Development of Computer Graphics
z Input Devicesy early light pens to modern micey data tablety touch sensitive screensy 3D input devices (spaceballs etc.)y button and dial boxes