Number Model Review

Things to know:

1. Animation following the graph of an equation:

   • Computer coordinates
   • People coordinates

2. Repetition using remainder.

3. Max/min to keep values large/small.

4. Randomness

   • Range of random numbers (e.g., 10<=x<=50).
   • Write and test a non-random function first.

5. Write checks for a function that you do not yet know how to write.

Terms:

• Computer coordinates: (0,0) in the upper left, positive y going down.
• People coordinates: (0,0) in the center, positive y going up.

Sample code:

• People coordinates demo

Review Problems

1. Make a sunset: a half circle.

   • shrinks in radius
   • changes color from red(ish) to black as the sun sets. (Advanced: yellow to magenta.)

2. Make a point that follows the graph of the equation y=((x-50)/10)^2

   • Use “people coordinates”. Each quadrant should be 75x100.
   • Move from x=-75 to x=75 in people coordinates.
   • Repeats the path from over and over.
   • Hit a key make the point go to x=0 people coordinates (and start moving).
   • Move the mouse to make the point move. (The point should seem to move faster when you move the mouse.)

3. Make a rectangle that is three times as wide as it is tall.

   • Height is determined by y-coordinate of the mouse.
   • Height decreases 5 units every time you hit a key.
   • Height cannot go below 20 units using key.
   • Height cannot go above 150 units using mouse.
   • You choose the color. (Advanced: color of grey depends on y-coordinate.)

4. (Maybe omit.) (… feel free to skip.) Make a line that you can move up and down with the mouse.

   • Straight line through x=0, y=70
   • Passes through the point where the mouse is sitting.

Information Flow for Question 2