Development of Computer Graphics z 1951 y Whirlwind, Jay Forrester (MIT) y CRT displays z mid 1950s y SAGE air defense system y command & control CRT, light pens z late 1950s y Computer Art, James Whitney Sr. y Visual Feedback loops z 1962 y Sketchpad, Ivan Sutherland y data structures, light pen for drawing and choices 1/20/2000 CS 4/57101 Lecture 2 1 Development of Computer Graphics z Early display devices (mid-60s): z Vector, stroke, line drawing, calligraphic displays z Architecture of Vector Display 1/20/2000 CS 4/57101 Lecture 2 2 Development of Computer Graphics z Architecture of a vector display - random scan y vector generator converts digital coordinates to beam deflections 1/20/2000 CS 4/57101 Lecture 2 3 Development of Computer Graphics z 1964 y CAD and CAM y General Motors DAC, Itek Digitek for Lens Design z 1964-1970s y Photorealism at University of Utah y Sutherland, Evans, Catmull, Blinn z 1968 y Evans & Sutherland y commercial company - flight simulators y 3D vector pipeline, matrix multiplier, clipping z 1969 y First SIGGRAPH 1/20/2000 CS 4/57101 Lecture 2 4 Development of Computer Graphics z 1970 y Pierre Bezier - Bezier curves 1/20/2000 CS 4/57101 Lecture 2 5 Development of Computer Graphics z 1971: y Gouraud Shading 1/20/2000 CS 4/57101 Lecture 2 6 Development of Computer Graphics z 1974-1977 y Catmull - Z-buffer y Bui-Toung Phong creates Phong Shading (Utah) y Martin Newell's teapot (Utah) y Computer graphics at NYIT - computer animation y Raster Graphics (Xerox PARC, Shoup) 1/20/2000 CS 4/57101 Lecture 2 7 Development of Computer Graphics z Architecture of a raster display 1/20/2000 CS 4/57101 Lecture 2 8 Development of Computer Graphics z Architecture of a raster display - raster scan y beams (3 beams) intensity set to reflect pixel intensity y scan speed: originally 30Hz now 60Hz 1/20/2000 CS 4/57101 Lecture 2 9 Development of Computer Graphics z Raster Scan y need to store whole image y 1024 x1024 x n - n bits per pixel y 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 1/20/2000 CS 4/57101 Lecture 2 10 Development of Computer Graphics z Random Scan versus Raster Scan y note ragged lines 1/20/2000 CS 4/57101 Lecture 2 11 Development of Computer Graphics z Random Scan versus Raster Scan z Raster advantages: y low cost, superior fill ability, refresh rate independent of complexity, 70Hz sufficient to avoid flicker z Raster disadvantages: y discrete nature of pixel representation, need for scan conversion in software or RIP chips x real-time dynamics more demanding y approximation of lines by sequence of pixels x aliasing - jaggies or staircasing x manifestation of sampling error in signal processing x need for anti-aliasing 1/20/2000 CS 4/57101 Lecture 2 12 Development of Computer Graphics z 1976 y Image and texture mapping (Blinn) z 1977 y 3D Core Graphics System, y first “standard” for device independent graphics package y allowed portable graphics programming y ACM SIGGRAPH committee including Foley, Van Dam, Feiner y baseline specification - many implementations 1/20/2000 CS 4/57101 Lecture 2 13 Development of Computer Graphics z 1982 y Clarke, Geometry Engine x hardware support for transforms (matrix-vector multiplies), clipping (variant of Sutherland-Hodgman algorithm) y IRIS - Integrated Raster Imaging System, SGI x high-end workstation x hardware acceleration of graphics pipeline z 1982 y TRON, Star Trek - Genesis Effect 1/20/2000 CS 4/57101 Lecture 2 14 Development of Computer Graphics z 1982 y Ray Tracing, Turner Whitted z 1983 y VRAM, Video random access memory, Texas Instruments x can read out all pixels in one memory cycle 1/20/2000 CS 4/57101 Lecture 2 16 Development of Computer Graphics z 1983 y Fractals 1/20/2000 CS 4/57101 Lecture 2 17 Development of Computer Graphics z 1985 y Radiosity, Don Greenberg (Cornell) y GKS, Graphical Kernel System x first ANSI standard x elaborated cleaned up version of CORE but only 2D z 1986 y Renderman z 1988 y GKS, Graphical Kernel System - 3D version 1/20/2000 CS 4/57101 Lecture 2 18 Development of Computer Graphics z 1988 y PHIGS, PHIGS+ y Programmer’s Hierarchical Interactive Graphics System y More complex than CORE 1/20/2000 CS 4/57101 Lecture 2 19 PHIGS v GKS z GKS allowed grouping of primitives into “segments” y no nesting of segements z PHIGS allowed nested hierarchical grouping of 3D primitives into “structures” y all primitives subject to geometric transformations y editable database of structures y auto-update of screen when database altered z PHIGS+ y extension for pseudo-realistic rendering on raster devices z PHIGS, PHIGS+ large packages y run best with hardware support of transforamtions, clipping and rendering 1/20/2000 CS 4/57101 Lecture 2 20 Development of Computer Graphics z 1993 y OpenGL - Open Graphics Library y derived from SGI’s GL library z 1993 y Open Inventor, OO layer on OpenGL z 1995 y QuickDraw 3D, Apple z 1995 y Direct3D, Microsoft, game playing API 1/20/2000 CS 4/57101 Lecture 2 21 Development of Computer Graphics z Input Devices y early light pens to modern mice y data tablet y touch sensitive screens y 3D input devices (spaceballs etc.) y button and dial boxes 1/20/2000 CS 4/57101 Lecture 2 22.