Alice:
A Visual Introduction to Programming
Chapter 1 Part 2
Objects
 Alice uses objects
o
o
o
Tent
Soldier
Princess
 Objects perform
actions
– Turn
– Move
– Fly
– Wave
1-2
The Alice System
1-3
Open SnowLove in Examples
1-4
Executing Alice Program
PLAY
1-5
Controlling Runtime Speed
Can increase speed of program
 Move slider of speed control

Useful when troubleshooting to skip over
parts of program that work
 Max of 10x normal

1-6
The Alice Environment
Scene
Editor or
World
View
Toolbar
Object Tree
Details
Panel
Events
Editor
Tile
Tile
Method
Editor
1-7
Checkpoint
How do you control the speed of an Alice
program that is being played?
 What part of the Alice environment displays
a view of the world?
 What part of the Alice environment displays
a list of objects in the world?
 What is a tile?

1-8
Objects
Anything that can be identified as
unique from other things
 How is an object unique?

o
o
Has a name
Has properties
 Color,
o
opacity, etc.
Can perform actions (methods)
 Associated
actions (move, turn , think, etc.)
 Tasks it can carry out
1-9
Object Properties
Object
Selected
Object
Selected
Change
Properties
1-10
Opacity

How transparent an object is
o
Less opaque an object, more transparent
 Opacity
of 100%, cannot see through the object
 Opacity of 0%, object is completely transparent

Like clear glass
An object with opacity of 0% is invisible
 A partially transparent object can be used to

o
o
Make something look far away in water
Have a ghostly appearance
1-11
Objects and Object Parts


Objects are made of
other subparts
Snowman made of:
o
head





topHat
leftEye
rightEye
carrotNose
mouth
leftArm
o rightArm
o Bottom
Objects named in “camel
Case” format
o

o
o
1st letter is lower case
Upper case next word’s 1st letter
1-12
Methods

Methods
o
o
Set of
instructions to
perform task
Default method
 world.my
method
first
1-13
Methods
 Each object and its
subparts can be
manipulated with
methods
o
o
o
o
Move
Turn
Roll
Say…
1-14
The World is an Object
 Contains all other
objects
 Also has its own
properties
o
o
o
Atmosphere color
Lighting
Fog
1-15
Checkpoint
What are properties?
 What is the name of a property that

o
o
Determines an object’s color?
Allows you to see through an object?
What is a method?
 What do you call a part of an object that can
move by itself?

1-16
Alice has Class(es)
 Objects are created
from classes
 Blueprint that
describes a particular
“type” of object
 Defines a particular
kind of object
Animals Collection
1-17
Classes



Gallery - collection of different object types
(animals, beach, people, etc.).
Class - each item found in the Gallery
Two galleries are used
o
o
Local gallery (stored on computer)
Web gallery (maintained by creators of Alice)
1-18
Class Instance in Alice
 Class: Chicken
 Instance: An object that

is created from a class
Examples
o
o
o
Chicken
Chicken2
Chicken3
 Each instance has its own

properties, methods,
functions
Can manipulate each one
individually
1-19
Creating a New World
•
Create a new world
o
o
File  New
Choose template
1-20
Adding Objects
Click on Add Object
1-21
Adding Objects: Scene Editor
Click on People
collection thumbnail
1-22
Add Coach

Place
object in
scene
editor by
Clicking
on it
o Or drag it
o
1-23
1-23
Coach Object With Bounding Box
1-24
Saving Alice World

Click on File then Save World

Has .a2w extension
1-25
Demo: Saving a world

Writing and testing an animation is an
intense load on the computing system
o
Crashes can occur
 Best


solution
Save your world every 15 minutes
Also save to a backup system

Ex: USB flash drive
1-26
Checkpoint





What is a class?
Are classes or objects stored in Alice galleries?
What are two ways to add an object to a scene?
What appears around an object when selected?
Where do you find an object’s properties?
1-27
3D Objects and the Camera
 Alice world and
objects are threedimensional
}
Height
2D
o Width
objects
– Depth – 3rd dimension
o
1-28
3D Movement
Forward
is based
perceived
as the object getting
Motion is
on OBJECT’s
larger
as it gets closer
us.Coach’s right
perspective…our
left istothe
Backward is perceived as the object
getting smaller as it gets farther away
from us.
1-29
The Camera
When you create an Alice world a camera is
automatically placed in the world
 Displays image of world in Scene Editor
window

o
Called camera viewpoint
1-30
Camera Controls

Drive forward, backward, turn left and right

Move camera up,
down, left, right

You can make camera move faster by dragging mouse
pointer away from center of camera control
Tilt camera up, down
1-31
Different World Perspectives



Sometimes difficult to tell
where object is in
relation to other objects
Fish looks like it should
be in water
Change world
perspective
o

Look at fish from
perspective of water
instead of sky
Also called Camera
control or point of view
1-32
Homework


Read chapter 1
Do tutorials
o
o
o

Tutorials 1-1, p 6
Tutorials 1-2, p. 19
Tutorials 1-3, p. 34
Due one week after assigned with 1 week grace
1-33