1. CSC 461: Lecture 1 1 Lecture 1: Introduction Objectives Explore what computer graphics is about Survey some application areas Introduce a history of computer graphics

2. CSC 461: Lecture 1 2 Computer Graphics Deals with all aspects of creating images with a computer –Hardware –Software –Applications Example –Where did this image come from? –What hardware/software did we need to produce it?

3. CSC 461: Lecture 1 3 Preliminary Answer Application: The object is an artist’s rendition of the sun for an animation to be shown in a domed environment (planetarium) Software: Maya for modeling and rendering but Maya is built on top of OpenGL Hardware: PC with graphics cards for modeling and rendering

4. CSC 461: Lecture 1 4 Basic Graphics System Input devices Output device Image formed in FB

5. CSC 461: Lecture 1 5 Frame buffer A portion of memory storing pixels – to be mapped to the display Pixels – picture elements encompassing a picture Picture – produced as array -- the raster – of pixels Video/Dynamic Random-Access Memory (V/DRAM) – fast redisplay of contents of frame buffer Depth of frame buffer – number of bits used for each pixel, such as color, lighting, shading, material, etc. Resolution – number of pixels in the frame buffer Colors – true color (RGB-color), indexed color (discrete color)

6. CSC 461: Lecture 1 6 Cathode-Ray Tube (CRT) – most PCs Calligraphic CRT – line-drawing device, random scan, electron beam emits from any position to any position Raster mode CRT – display the contents of the frame buffer at a rate high enough to avoid flicker Screen refresh rate – typical CRTs emit light for only a few milliseconds, redisplay the pictures in a frequency Two display methods –Noninterlaced – pixels displayed row by row, the rate 50- 85 (Hz) times/second – used in computer systems –Interlaced – odd rows and even rows refreshed alternately, first draw at 60 Hz, the refresh rate 30 Hz

7. CSC 461: Lecture 1 7 CRT Can be used either as a line-drawing device (calligraphic) or to display contents of frame buffer (raster mode)

8. CSC 461: Lecture 1 8 Other Raster Mode Output Devices Liquid-Crystal Display (LCD) – raster mode, used in laptops, may or may not be refreshed Plasma panel – raster mode, used in TVs

9. CSC 461: Lecture 1 9 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

10. CSC 461: Lecture 1 10 Computer Graphics: 1960-1970 Wireframe graphics Project Sketchpad Display Processors Storage tube

11. CSC 461: Lecture 1 11 Project Sketchpad Ivan Sutherland’s PhD 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

12. CSC 461: Lecture 1 12 Display Processor Rather than have host computer try to refresh display use a special purpose computer called a display processor (DPU) Graphics stored in display list (display file) on display processor Host compiles display list and sends to DPU

13. CSC 461: Lecture 1 13 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

14. CSC 461: Lecture 1 14 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

15. CSC 461: Lecture 1 15 Raster Graphics Image produced as an array (the raster) of picture elements (pixels) in the frame buffer Allow us to go from lines and wireframes to filled polygons

16. CSC 461: Lecture 1 16 PCs and Workstations Although we no longer make the distinction between workstations and PCs historically they evolved from different roots –Early workstations characterized by Networked connection: client-server High-level of interactivity –Early PCs included frame buffer as part of user memory

17. CSC 461: Lecture 1 17 Computer Graphics: 1980-1990 Realism comes to computer graphics smooth shadingenvironmental mapping bump mapping

18. CSC 461: Lecture 1 18 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)

19. CSC 461: Lecture 1 19 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

20. CSC 461: Lecture 1 20 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