1. CS320n – Elements of Visual Programming
Alice Concepts
Mike Scott
(Slides 1-2)

2. What We Will Do Today Finish the material in chapter 1
Continue working on the tutorials and appendix 1 material in Alice
Visual Programming
Alice Concepts

3. Types of Animation Two kinds of Alice animations Movie Interactive
User “watches” animation
“machine-centric”
Interactive
User participates – clicks mouse, controls actions with keys
“user centric”
Visual Programming
Alice Concepts

4. Events Animations that are “interactive depend on the user’s actions
mouse click
key press
others (head mounted device, dance pad)
Actions are events
Interactive programs are event driven
Event window portion of Alice
Visual Programming
Alice Concepts

5. Interactivity in Alice
Animation with no interaction
Movie
DEMO Octopus Ride
Animation with interaction
DEMO Ice Skater
What are the events?
What response does the skater make to each event?
Visual Programming
Alice Concepts

6. Objects What is an object? What makes an object unique?
anything that can uniquely identified from other things
What makes an object unique?
has a name
has properties
width, height, color, location, age, id#
has a purpose
associated actions it can perform
tasks it can carry out – things it knows how to do
Visual Programming
Alice Concepts

7. Classes Objects are categorized into classes
Each objects is an instance of the class
All objects in a class
have the same properties
generally can perform the same tasks
Rico
Skipper
Penguins
Private
Snoopy
Kowalski
Dogs
Odie
Opus
Ren
Visual Programming
Alice Concepts

8. Objects in a Virtual World
In Alice, each 3D model is a class of objects
class: penguin
objects: penguin, penguin1, penguin2
Visual Programming
Alice Concepts

9. Changing Properties of Obejcts
Properties of Object can be changed
Location can be changed by clicking and moving object
Orientation can be changed in the “Add Objects” View
Other properties, such as color, can be changed in the properties window when the object is selected
Visual Programming
Alice Concepts

10. Object Parts Objects may be composed of parts
which may in turn be composed of parts
the whole object may be told to do something or an individual part
Visual Programming
Alice Concepts

11. Center of an Object each object has center point
usually near center of mass, but really set by graphic artist that created object
spin point for object
things that sit or stand on ground usually have center between feet
things that are held have center at point object would be held
Visual Programming
Alice Concepts

12. Distance
object’s distance from each other are based on the distance between their center points
may look like objects are zero distance away, but actually centers still some positive distance away
Visual Programming
Alice Concepts

13. Position in the World The world in an Alice program models a 3D space
every object in the world has a position x, y, z, coordinate relative to the center of the world
ground starts at center of world
axes (green = up, red = right, blue = forward)
Visual Programming
Alice Concepts

14. Adding 3D Text Under the “Add Objects” window
Creates a 3D Text Object that can be positioned in the scene
Like other objects it has a host of behaviors and properties
Visual Programming
Alice Concepts

15. Adding “Billboards” Billboards are flat, 2D images in a scene
Almost any graphic type can be added.
GIF, JPG, TIF, PNG, BMP
Select file and image is added to scene
Images must be created is some other program
Visual Programming
Alice Concepts

16. Visual Programming
Alice Concepts

17. Class Work Continue work on tutorials Appendix A, Part 1
Part 2: Using Pop up menus to create an initial scene.
Visual Programming
Alice Concepts