Angel6E01Computer basicsComputer basicss
- 1. 1 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 What is Computer Graphics? Ed Angel Professor Emeritus of Computer Science, University of New Mexico
- 2. 2 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Objectives •In this lecture, we explore what computer graphics is about and survey some application areas •We start with a historical introduction
- 3. 3 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Computer Graphics •Computer graphics deals with all aspects of creating images with a computer - Hardware - Software - Applications
- 4. 4 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Example •Where did this image come from? •What hardware/software did we need to produce it?
- 5. 5 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 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 card for modeling and rendering
- 6. 6 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Basic Graphics System Input devices Output device Image formed in frame buffer
- 7. 7 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 CRT Can be used either as a line-drawing device (calligraphic) or to display contents of frame buffer (raster mode)
- 8. 8 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 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
- 9. 9 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Computer Graphics: 1960-1970 •Wireframe graphics - Draw only lines •Sketchpad •Display Processors •Storage tube wireframe representation of sun object
- 10. 10 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 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
- 11. 11 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Display Processor • Rather than have the 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
- 12. 12 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 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
- 13. 13 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 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
- 14. 14 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Raster Graphics •Image produced as an array (the raster) of picture elements (pixels) in the frame buffer
- 15. 15 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Raster Graphics •Allows us to go from lines and wire frame images to filled polygons
- 16. 16 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 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 model • High-level of interactivity - Early PCs included frame buffer as part of user memory • Easy to change contents and create images
- 17. 17 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Computer Graphics: 1980-1990 Realism comes to computer graphics smooth shading environment mapping bump mapping
- 18. 18 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 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. 19 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Computer Graphics: 1990-2000 •OpenGL API •Completely computer-generated feature- length movies (Toy Story) are successful •New hardware capabilities - Texture mapping - Blending - Accumulation, stencil buffers
- 20. 20 Angel and Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 Computer Graphics: 2000- •Photorealism •Graphics cards for PCs dominate market - Nvidia, ATI •Game boxes and game players determine direction of market •Computer graphics routine in movie industry: Maya, Lightwave •Programmable pipelines