development of computer graphicsfarrell/cg01/lectures/cg02-6.pdf · development of computer...

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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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z Early display devices (mid-60s):z Vector, stroke, line drawing, calligraphic displaysz Architecture of Vector Display

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z Architecture of a vector display - random scany vector generator converts digital coordinates to beam

deflections

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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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z 1970y Pierre Bezier - Bezier curves

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z 1971:y Gouraud Shading

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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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z Architecture of a raster display

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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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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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z Random Scan versus Raster Scany note ragged lines

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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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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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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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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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z 1983y Fractals

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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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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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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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z Input Devicesy early light pens to modern micey data tablety touch sensitive screensy 3D input devices (spaceballs etc.)y button and dial boxes

development of computer graphicsfarrell/cg01/lectures/cg02-6.pdf · development of computer...

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