CS488 - Introduction to Computer Graphics - Lecture 2

Comments and Questions

  1. Combination to graphics lab.
  2. Location of TAs: DC2303.
  3. Class cancelled: March 11, 2008.

Output Devices

Main device from the beginning (1970s) was the colour cathode ray tube (CRT).


Main components

  1. Electron beam
  2. Focussing and acceleration electrodes
  3. Beam steering electrodes
  4. Phosphor

Operational principle -- Persistence of vision

Types of CRT

  1. Vector, aka calligraphic
  2. Raster -- operational principle
  3. Colour raster -- operational principles

Benefits of CRT

  1. Very inexpensive
  2. Good resolution
  3. Easy colour calibration
  4. High contrast
  5. Good field of view
  6. Comet-free motion
  7. Adjustable focus

Drawbacks of CRT

  1. Heavy and big
  2. Power hungry
  3. High voltage
  4. Dim


Key components

  1. Back light
  2. Programmable filters -- one per colour primary per pixel


  1. small
  2. light
  3. not as power hungry as CRT

Disadvantages - most of these are back light problems

  1. directional view
  2. back light consumes power
  3. not very bright
  4. poor extinction
  5. hard to calibrate colour

Others of the past

Others of the future

Output Abstraction

Input Devices

Two types of device

  1. Text input devices
  2. Pointing devices

Device input modes

  1. Request
  2. Sample
  3. Event

Modes can operate differently at hardware and software levels.

Input Abstraction

Event-based programming

  1. Event loop
  2. Callbacks

Events can be as simple or elaborate as you like

Extra Layer of Output Abstraction

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