Alice

1
Alice

• Chapter 3 61 - 75

2
Objectives

• To understand Event Driven Programming
• To understand three dimensional space, in Alice
• To learn how to use events in Alice

3
Event Driven Programming

• Events provide users control to manipulate
  objects in 3-dimensional space

4
Event Driven Programming

• Event trigger
• A condition causing an event to occur
• Ex pressing the enter key
• Event handler
• Activated based upon a trigger
• Ex object spins

5
1 Dimensional Space

• A way of measuring something on a scale
• Distance from a starting point (-1)
• Direction negative or positive (negative)
• -3 -2 -1 0 1 2 3
• Quantification assigning values on a scale

6
1 Dimensional Space

• Scale of measurement
• Absolute direction an object is facing
• Forward or Backward
• -3 -2 -1 0 1 2 3
• Only the race car is forward

7
1 Dimensional Space

• Point of view in relation to other objects
• Object Relative direction
• Forward or Backward
• -3 -2 -1 0 1 2 3
• Only the race car is progressing backward
• Green car is behind cat, race car is in front of
  cat

8
1 Dimensional Space

• Point of view
• Orientation location
• absolute direction object-relative direc

9
1 Dimensional Space

• Ideas of direction
• Absolute
• Known through a scale of measurement
• Ex the cat is backward -1 0
  1
• Object-relative
• In relation to another object
• Ex the cat is facing forward from the car

10
1 Dimensional Space

• Ideas of direction
• -3 -2 -1 0 1 2 3
• Object relative position (in front and behind)
• Car is behind the swan, who is in front of the
  penguin

11
Two Dimensional Space

• Scales of measurement on a flat surface
• Cartesian coordinates
• (x, y) ordered pair on x and y axis
• Dimension (x) is listed first
• Ex age and height of siblings
• (9, 4), (14, 5), (18, 6)
• Examine the next slide

12
Two Dimensional Space

• Scales of measurement on a flat surface
• Cartesian coordinates
• Ex age and height of siblings (9, 4), (14,
  5), (18, 6)
• Height
• Age

18, 6
14, 5
9, 4
13
Start Three Dimensional Space

• Third axis
• Height (z) above or below the plane
• Ordered triplet
• (x, y, z) orientation in 3-dimensional space

14
Three Dimensional Space

• Euclidean space
• Wrote about physical world geometry in
  dimensional space
• This is Alice

15
Three Dimensional Space

• Alices Euclidean 3D space
• Six object relative directions
• x right or left
• y backward or forward
• z down or up

16
Three Dimensional Space

• Alices Euclidean 3D space
• Six object relative positions
• x right of or left of
• y behind or in front of
• z below or above

17
Events In Alice

• Open the amusementPark world
• Welcome screens examples tab
• Notice the major event tiles
• Camera arrow key controls
• When the World starts .

18
Events In Alice

• The top tile
• Moving the camera

19
Events In Alice

• Create a World level method
• World tile
• Create new method button
• Name the new method

20
Events In Alice

• Create a World level method
• Drag a tile (Do Together) from bottom of Editor
  area over the new methods Do Nothing

21
Events In Alice

• Create a World level method
• Finish creating the new method
• Drag methods from Details area into Do Together
  tile

22
Events In Alice

• The event handler
• Add the new method to the default event tile as
  the event handler
• Select World
• Drag the new methods tile over the World.my
  first method in the Events area

23
Events In Alice

• Remove (delete) the world.my first method from
  the details area

24
Event Types

• 9 types under Create New Event Button

25
Event Types

• Choose any event (ex When the world starts)
• New event tile appears

26
Event Types

• Changing the form of the event
• Run continuously (loop)
• Right click the event tile background
• Event menu appears

27
Event Types

• Event menu choices
• Delete
• Change to
• To change the form
• Disable
• Non functional to enabled

28
Event Types

• Event menu
• Change to
• To change the form

Becomes
29
Event Types

• While the world is running event tile
• 3 different event handler positions (for
  methods) Begin, During, End

30
Event Types

• The 3 handlers are also known as BDE
• To establish the handlers
• Drag method tiles into the BDE areas, over the
  ltnonegt

31
Event Types

• When a key is typed event
• Add controls or user interaction
• Two parameters
• Ex Trigger pressing a key
• Ex Handler a method making an object turns
• Examine the next slide

32
Event Types

• Click anykey down arrow

Drag a method over Nothing.
When the World runs, a key is typed, and the
method runs
33
Event Types

• While a key is pressed event
• Loops while triggering key pressed
• Changes
• To

First, right click blue area
34
Event Types

• While a key is pressed event
• Drag a method over Durings ltNonegt
• The method runs as long as B is held down

35
Event Types

• When the mouse is clicked
• We can choose a target object to be clicked on

Drag a method to