ITC 101 Programming Module

Exploring Computer Programming with Alice

Middlesex Community CollegeIntroduction to Technology

Fall 2011Prof. Lori Weir

[email protected]

mailto:[email protected]?subject=Summer%20Bridge%202010%20Alice%20Presentation

mailto:[email protected]?subject=Summer%20Bridge%202010%20Alice%20Presentation

Fall 2011

Student Learning Outcomes

• Introduction to Computing Careers• Introduction to Alice• Setting up an initial scene in Alice• Designing an animated scenario• Implementing a design• Programming• Summary• Going forward

2Middlesex Community College

Middlesex Community College <<DRAFT>>

INTRODUCING ALICEGetting Started with Visual Programming

Fall 2011 3


What is Alice?

• Alice is a visual programming language.• Alice is an object based language. The

objects in Alice are 3 dimensional models.• The output of Alice programs is an

animation.– Objects can be made to move around the

virtual world:• A video game• A simulation

Fall 2011 4


The Alice Software

• A 3D interactive animation environment• http://www.alice.org/• A tool for teaching fundamental programming

concepts– object based

• System developed at Carnegie Mellon

Fall 2011 5

http://www.alice.org/


Visual Programming

• Programming tasks are performed in an Integrated Development Environment(IDE).

• Programming is done by pointing and clicking, dragging and dropping, selecting from menus, and some typing.

• Syntax errors removed from the equation– no braces, no semi colons

Fall 2011 6


Object Tree World View Event Editor

Details PanelCode Editor Control

PrimitivesFall 2011 7


Object-Based Programming

• Built in library of models.• More available on the web.• All objects have certain methods and

behaviors – move, turn, say, roll, resize

• New methods can be added to an object

Fall 2011 8


Alice Models

• Main programming data are 3d models• Many built in and more on web

Fall 2011 9


Output

• Output is a 3d movie– run the program, play

a movie– can also add sound to

programs

• Much easier to recognize logic errors– "Why do my

ninja's armskeep flyingaway?"

Fall 2011 10


11

ACTIVITY 1Downloading and Exploring Alice Worlds

Fall 2011


Fall 2011

Downloading Alice

• From your browser, navigate to the Alice download page:http://www.alice.org/index.php?page=downloads/download_alice

• Follow the instructions for your platform (Windows, Linux, or MAC).

12

http://www.alice.org/index.php?page=downloads/download_alice

http://www.alice.org/index.php?page=downloads/download_alice


Fall 2011

Exploring Alice Worlds

• Open Alice from the DeskTop• Load and run a world:

– Octopus (movie)– Skater (interactive)

13


Fall 2011

Types of Animation

Movie

• Passive• User watches the

animation

Interactive

• User clicks on mouse or types a key on the keyboard.

• Actions of user are called events

14


15

SETTING UP A SCENE IN ALICE

Getting Started Programming in Alice

Fall 2011


Alice Programming

• Problem solving and programming in Alice– given a scenario create program to enact the

story• Example scenario:

– A bunny is hopping in a field of fern and one tulip.

– The bunny notices the tulip.– The bunny hops over to the tulip.– Accidentally, the bunny knocks the tulip.

Fall 2011 16


Creating a New World

Fall 2011 17


Selecting a Template

Fall 2011 18


Objects in The World

• An object is:– Any thing that can be identified as unique

from other things.• How is an object unique?

– Name– Properties

• Width, height, color, location

– Can perform actions• Referred to as methods

Fall 2011 19


Adding Objects to the World

Fall 2011 20


Adding Objects

• Two ways to add objects:– Drag and

Drop– Click on

picture then click on Add Instance

Fall 2011 21


Fall 2011

Techniques and Tools

Mouse is used to

Approximately position objects in the scene.

22


Mouse Control Tools Kit

Default. Move selectedobject left, right, forward, backwards.

Move selectedobject up and down.

Turn object left and right.Turn object forwards andbackwards.

Tumble objects.

Resize objects.

Copy objects.

CTRL Z or Undo Button to undo mistakes!Fall 2011 23


Camera Controls

Alter position of camera with these controls.Fall 2011 24


Alternate Positioning Techniques

• Right click on object in world on object tree and select method

• Drag and drop method from the details panel.

Fall 2011 25


Quad View

• Use world's absolute frame of reference to view relative position of objects

Fall 2011 26


Fall 2011

Objects Frame of Reference

• Objects in Alice– Have their own frame of reference– forward – backwards– up – down– left – right

27


Frame of Reference

• Clicking on object brings up its bounding box

• Can also see center point

• .. and axes

Fall 2011 28


Frame of Reference

UP

RIGHT

FORWARD

CENTERPOINT

Fall 2011 29


Subparts

• Objects often have sub parts– may have their own frame of

reference• Clicking affect subparts box

allows selection and movement of subparts

Fall 2011 30


Subparts

• Bigger ear

Fall 2011 31


Finding Objects

• To reposition in a quad view– select zoom in and out

from mouse controls– zoom way out– select scroll from

mouse controls to center objects

– zoom back in

Fall 2011 32


Back to Programming View

• When setup complete click the green done button to go back to the programming view.

Fall 2011 33


Fall 2011

Saving a World

• Writing and testing an animation is an intense load on the computing system – a crash can occur.

• Best solution– Save your world very 15 minutes (or at least

every half hour).– Also, save to a backup device

• Zip drive• Memory key

34


35

ACTIVITY 2Creating a World

Fall 2011


Setting Up the Initial Scene

• From the Alice programming environment:1. create a new world.

2. Add bunny

3. Add fern and flower• local gallery -> nature

– Fern– Tulip

4. Resize bunny to make her smaller• Use the drop down menus

or drag and drop

October 16, 2011 36


37

PROGRAMMING THE WORLD

From a storyboard to a program

October 16, 2011


Fall 2011

Step 1: Design

• A program is a solution to a problem.• Determine the problem to be solved.• Design a solution to the problem.

– We will use a storyboard design technique.– Commonly used in the film and gaming

industries.

38


Example Story

• A bunny is sitting in a field of fern.• The bunny notices a beautiful tulip.• The bunny hops over to tulip.• The bunny accidentally knocks over the

tulip.• Let's add some detail at the start of the

movie. – The bunny first turns to face the camera. – Then the bunny hops up and down.

Fall 2011 39


Fall 2011

Options for Storyboards

• Sketches• Screen shots from Alice• Text

– A to-do list of steps

40


Fall 2011

Step 2: Implementation

• To implement the storyboard, translate the actions in the storyboard to a program.

• Program (a.k.a. script)– A list of instructions to have the objects

perform certain actions in the animation.

41


Fall 2011

Action Blocks in Alice

42

Sequential Action BlockActions occur one after another

Simultaneous Action BlockActions occur at the same time


Fall 2011

Concepts in this First Program

• Program instructions may have arguments– Example: for the move instruction, the

arguments we used where:• Direction• Distance

– Do Together and Do In Order blocks can be nested one inside the other

43


Fall 2011

Testing

• An important step in creating a program is to run it – be sure it does what you expect it to do.

• We recommend you use an incremental development process:– Write a few lines of code, then run it– Write a few more lines of code, then run it– Write a few more lines or code…

44


Fall 2011

Comments

• While Alice instructions are easy to understand, a particular combination of the instructions may perform an action that is not immediately obvious.

• Comments document the code – explain the purpose of a particular segment of the program to the human reader.

45


Methods

• Select the world object from the object tree and the methods tab in the details panel.

• The world starts with a single method, "my first method"

• Like main in a Java or C++ program.

Fall 2011 46


47

ACTIVITY 3Adding to ‘My First Method’

October 16, 2011


Fall 2011

Adding Commands to a Method

• If the "my first method" is not displayed in the code editor click the edit button next to the method in the detail panel.

• Commands are added by dragging and dropping them into a method.

• Select the bunny from the object tree.• Drag the turn to face command into the

code editor.• TEST!

48


Adding Commands• turn to face is a method• When adding a method to

the code editor if any parameters are required a menu pops up to select the arguments.

• Select thecamera.

Fall 2011 49


Fall 2011

More Parameters

• After adding the bunny.turn to face command the "my first method" will look like this:

• Click on the "more" option to see what other parameters can be changed– duration, style, asSeenBy– change duration to 3 seconds

50


Test

• Click the play button to see the movie / output of the program.

• "my first method" will execute.

Fall 2011 51


PROGRAMMING: PUTTING TOGETHER THE PIECES

Built-in Functions and Expressions

Fall 2011 52


Adding Behaviors

• Next we want the bunny to hop. • Methods can be world level or class

level.– world level methods belong to the world.

• a method should be world level method if it involves two or more objects

– class level methods belong to a particular class / object.• a method should be a class level method if it

involves only one object

Fall 2011 53


Creating a Hop Method

• The bunny does not have a hop method so we will create one.

• Select the bunny from the object tree and click on the create new method button in the details panel.

Fall 2011 54


Creating a Hop Method• A window pops up asking for the name

of the method– try various names to see what is a legal

identifier and what is not• After giving the new method a name a

new tab pops up in the code editor• Should hop be one hop or

parameterized? • Should parameter be time to hop or

number of hops to make?• Any other way to make it more general?

Fall 2011 55


Adding Parameters

• Let's add parameters for distance to hop up and the time to do the hop

• Click the create new parameter button in the code editor.

Fall 2011 56


Adding Parameters

• Give the parameter a name and pick the data type– distance -> a Number– time -> a Number

• When called the hop method now requires two parameters

Fall 2011 57


Adding Commands to Hop

• To hop the bunny will move up and then down.

• Drag the move command into hop and fill in the parameters.

• Drag another move command into hop and fill in the parameters.

Fall 2011 58



• To change the duration of moving up select the more option from the move command.

• Select duration then expressions then time (or the name of your parameter for time)

Fall 2011 59


Fall 2011


• To change the duration of the move to half of the time parameter click on the triangle to open the drop down menu.

• Select math and divide time by 2.• Do the same for the move down.

60


Completed Hop Method

Fall 2011 61


Back to my first method

• Now that the bunny can hop and the broccoli can grow we can complete the first part of the story board

• After the bunny turns to face the camera we want the bunny to hop.

Fall 2011 62


Hopping

• We want the bunny to hop for 5 seconds.• Back to my first method• Have rabbit hop up and down .25 meters

at 0.5 seconds per hop• How many hops?

Fall 2011 63


Fall 2011

Looping

• A counted loop is used when the number of repetitions can be calculated

• Drag a Loop primitive into the Do together block

• Number of times to loop is 10

64


Hopping

• After Loop is added to Do together• drag and drop the

bunny hop method into the loop

• Select 0.25 meters for distance to hop and 0.5 seconds for time

• Test!

Fall 2011 65


Noticing the Tulip

• Now we want the rabbit to – turn to face the tulip, – Think “Pretty!”– hop over to the tulip– Accidentally knock over the tulip.

Fall 2011 66


Test

• Test function by playing movie• Test further by changing initial set up of

broccoli to change which broccoli is closest

Fall 2011 67


Noticing the Tulip

• Do together• Bunny turn to face

tulip• Bunny thinks “Pretty!”• Tulip orients to bunny.

Fall 2011 68


Fall 2011

Hopping Forward

• Create a new method hopForward• Parameters for total distance and distance

per hop– lots of other ways to do this

69


Completing the Hopping

• Back in my first method call the hopForward method.

• Pick a dummy value for totalDistance.

• Replace dummy value with distance from bunny to tulip minus some offset. (no collision detection)

Fall 2011 70


71

ACTIVITY 4Testing your Knowledge

Fall 2011


72

Testing your Knowledge

• Working with a partner, make the flower shake and fall after the bunny stops hopping.

• What programming constructs do you need?

• Which methods will you use?

• What will the bunny say?

• Experiment with your closing camera position.

Fall 2011


Fall 2011

Exporting/Publishing

• Animated file• Web page

73

74Middlesex Community College <<DRAFT>>

What Next?

• Expand by adding more flowers– lists and variables to manage

• Add sounds• Add scenery• Add events

– Interactive programs can be created by adding events that program responds to.

Fall 2011


Fall 2011

Summary

• Learning Alice helps prepare you for an object-oriented language:– C++– Java

75


Adding Detail to the Hop Method

Fall 2011 76


Fall 2011

Going Forward

• Questions about computer science• Interest level?• Help

– Example worlds– Tutorial– www.alice.org

77

Date post:	13-Nov-2014
Category:	Education
Upload:	weirla
View:	606 times
Download:	3 times

ITC 101 Programming Module

Education