CS141: Topics for Feb 17, 19, & 21, 2014

• Lab: Continue Lab 3: Frieze Patterns. This will be due Mon, Feb 24.

• Symmetry examples

• Programming Elements for this Week

  • Modularizing code.
  • Functions with parameters. See example (pdf). Code is here - you will need to provide your own image.
  • Transformations: translate, rotate, scale.
    • Rotation and the fixed point (or pivot).
    • Scaling and the fixed point (or pivot).
    • Rotation, Translate, and Scale combined.
  • Matrix Stack: Recall practice problems from last week:
    • See practice exercise (pdf)
    • See practice exercise - loop (pdf)

• (if time) Strings and text in Processing (see reference for text()).

• Transformations can be used to create symmetry designs:

  • M. C. Escher
  • Islamic Geometric Art

• Begin discussion of Trig Functions:

  • Why is trig fun?!! See processing sketches using trig or see Fun with Sine
  • See Online: Trigonometry
  • How are sin and cos defined? How do they relate to the unit circle? See Greenberg demo.
  • What is the graph of y = sin(x) and y = cos(x)?
  • How do sin and cos relate to Processing's rotate command?