Intro to Alice Programming: Software Life Cycle

• General process describing steps used to develop programs:

1. Analyze

– Basic problem-solving

∗ Identifying exactly what the problem is

– Generate program requirements/specifications:

∗ Id input and output

2. Design

– Designing algorithms for various tasks

∗ Algorithm: Sequence of unambiguous steps used to solve a problemin a finite amount of time

· In Alice, this is represented by a story

– Identify program constructs and processing required to solve problem

∗ This where tools like story boards and flow charts are used

3. Implement

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Intro to Alice Programming: Program Design and Development -Animation/cinematic Hierarchy

• From the perspective of story creation, we can decompose plot using standardcinematic concepts:

1. Action

– Single parameterized change

2. Shot

– Continuous sequence of frames

– Represent single time span, single point of view

– Consist of one or more actions, all shot at same time

– Actions may span several shots

3. Scene

– One or more shots at a single location

– Represent a single topic

4. Sequence

– Group of related scenes that compose a major thematic component

5. Act

– Major cinematic division

– Marked by turning point

6. Play

– Plot carried out from beginning to end

– Intended to be viewed in one sitting

7. Serial

– Set of related plays of similar duration

– Contain common characters, locations, ...

– Plot may extend over multiple plays

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Intro to Alice Programming: Program Design and Development - Story Boards

• These are a means of representing story development

• There are two kinds:

1. Visual

– Storyboard is essentially an enhanced comic book

∗ Consists of a sequence of illustrated panels

∗ Panels are annotated

∗ May use sheets containing multiple panels, oruse one panel per sheet

∗ Use one or more panels per shot

∗ Panels labeled with scene

∗ Panels numbered as to shot

– 2 general purposes:

(a) Technical: specifies

∗ Actions

∗ Camera actions

∗ ...

(b) Artistic

∗ Mood

∗ Lighting

∗ ”Feel” of shots

∗ ...

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Intro to Alice Programming: Program Design and Development - StoryBoards (2)

– Examples:

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Intro to Alice Programming: Program Design and Development - StoryBoards (3)

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Intro to Alice Programming: Program Design and Development - StoryBoards (4)

– Contents of a storyboard may include

(a) Illustrations

∗ Purpose is to indicate

· Relative positions of characters and props

· Poses

· Camera specs

· ...

∗ Quality of artwork not critical

(b) Actions

∗ Indicated with arrows within the panel

(c) Camera actions

∗ Also indicated using arrows

∗ Appear below or beside panel

∗ Camera has 6 degrees of motion:

· 3 linear (along x, along y, along z)

· 3 rotational (about x, about y, about z)

∗ Linear motion:

i. Dolly - along z

ii. Truck - along x

iii. Boom - along y

∗ Rotational motion:

i. Pan (yaw) - about y

ii. Tilt (pitch) - about x

iii. Roll - about z

∗ Camera may also be zoomed

· Indicated as

2. Textual

– Instead of using pictures, this form simply describes what happens

– The description is in terms of actions that usually are close to the oper-ations available in the programming language being used

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Intro to Alice Programming: Classes and Objects

• Alice is an object-oriented language

– In object-oriented programming, you start with a class

∗ A class is a template - a description - a blueprint - a model - for creatingsomething

∗ A class is described by a set of prooerties (values) and a set of methods(actions)

– Objects are specific instances of a class

• In a story, objects correspond to nouns and methods to actions

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Intro to Alice Programming: The IDE

• An Integrated Development Environmet (IDE) is a graphical interface for de-veloping programs

• The following indicates the major components of Alice 3’s IDEThis is the Edit Code perspective

• The language preference should be set to Java

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Intro to Alice Programming: Programming in Alice

• Programming consists of creating a scene, adding objects to a scene (and settingtheir properties), and adding methods and control structures in the scene editor(by clicking Setup Scene in the Scene Viewer)

• A program is represented by a scene (called this)

• When you start Alice , you will be prompted to select a project (either a newone or one already existing)

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Intro to Alice Programming: Setting up a scene Alice

• To add objects to the scene, change to the Setup Scene perspective (using theobvious button), and dragging them into the scene from classes

• When adding objects to the scene, Alice will give them default names (basedon the class) that are numbered.

– It is usually advisable to give them unique, meaningful names of your own

– Alice’s naming conventions use camel case:The first letter of each embedded word is capitalized (but not the first forobjects)

• An object’s properties are displayed in a pane to the right

• Objects can be transformed using handles

– Translation (movement along X, Y , and Z axes)

– Rotation (along local X, Y , and Z axes)

– Scaling (change in size)

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Intro to Alice Programming: Setting up a scene Alice (2)

• An object tree is displayed in the upper left of the Setup Scene perspective

• Every scene has a camera whose controls are at the bottom of the pane

– By default, Setup Scene uses camera view

– This can be changed using the menu in the top center of Setup Scene

– These alternate view are useful for orienting objects wrt each other

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Intro to Alice Programming: Setting up a scene Alice (3)

• The Rule of Thirds: Impose a 3 X 3 grid on the scene. The main featuresshould line up on the intersections

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Intro to Alice Programming: Objects

• Each object represents a specific instance of a class

• A class provides a basic set of components for each instance created

– Properties are values that describe the instance

– Methods are actions that an object can take

∗ They implement the behavior of an object

∗ There are two types

· Procedures that produce no value

· Functions that produce a value

∗ Objects interact with each other by sending messages to each other (viamethods)

• Objects inherit the properties and methods of their class and customize theirvalues for that particular object

• Objects consist of a collection of other objects, each of which is an object inits own right

– To access an objects components:

∗ From the object tree (Setup Scene perspective)

∗ From the object drop down menu (Edit Scene perspective)

Select an object and expand using the black expansion arrow (triangle)

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Intro to Alice Programming: Creating a Program

• A program consists of a method that contains a sequence of statements

• Programming in Alice consists of adding statements to methods in the EditCode perspective

• The top-level default method is named myFirstMethod

• A statement is an instruction for the computer to execute

– There are several types:

1. Assignment

2. Method callsSyntax: object name.method name(parameter list)

3. Control

• Adding method calls to a program

– The procedures and functions associated with an object appear in the meth-ods area under the scene viewer in the Edit Code perspective

– They are dragged into the appropriate place in the editing pane

– If a method requires one or more parameters (values), they can be dragged,selected, or typed (depending on the method)

– The add detail button allows you to specify modifiers to the statement

– duration is used to specify how long the action takes

– Note that there is a hierarchy of methods: Those associated with a class,those with an object

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• Adding control statements to a program

– Control statements (among others) are listed underneath the editing pane

– They are dragged into the appropriate place in the editing pane

– doInOrder() executes its statements sequentially (one after the other)

– doTogether() executes its statements in parallel (all at the same time)

• performCustomSetup is a method that executes before myFirstMethod

– It is used to assign values and perform actions to set up a program beforeit starts running

– It can be added from the Scene tab of the editing pane

• To execute a program, click the Run button

• Don’t forget to save your project

– Alice 3 programs have a file extension of .a3p

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