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# Alice workshop v1_presentation_slides_v1.1

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Hui Seng, Boon Senior Program Manager of Oracle Academy given lecture at the venue of Punjab Youth Festival'2012

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• Optional activity: Talk about some examples of scenarios from the following categories: Theatrical plays and literature Subjects in school Simulation or demonstrations you have participated in Games you have played
• Flow charts are used by programmers to think out how their code will flow; this is especially useful when handling conditions. Flowchart Basics Triangle – This shape indicates a decision point Rectangle – This shape indicates a process to be completed; this could be a calculation or execution of a statement. Elongated circle – Ends the program A second example; this to work through with students. Have the students provide the flowchart for: If I see a spider, then I will scream, &quot;YAAHHHHAA!&quot;; otherwise, I will not scream (i.e., do nothing). Ask: What is the: Decision point True result False result
• A textual storyboard is an organized list of the sequential tasks that the program will execute in the animation.
• A textual storyboard is an organized list of the sequential tasks that the program will execute in the animation.
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples” Demonstration title: S02L04_Example_Move. The below code can be used to review the Move method:
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples”. Demonstration title: S02L04_Example_Move Toward. The below code can be used to review the move toward method: In this example the Alien moves toward the table. Amount - We can experiment with the distance moved by selecting different amounts; the greater the amount, the greater the object moves. Time – We can also experiment with the rate of speed that the Joey moves. Select the More instruction and select different durations.
• The below code can be used to review the move away method:
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples” Demonstration title: S02L04_Example_Move_To. Why is the Alien in the center of the sofa? The move to procedure is oriented to the objects&apos; center. After running the animation you will see the center of the Alien moves to the center of the sofa. This can be corrected by using the move command, to move the object up. (The delay command is not required.)
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples” Demonstration title: S02L04_Example_Orient_To. The below code can be used to review the orient to method: (The delay command is not required)
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples” Demonstration title:, S02L04_Example_Delay. The below code can be used to review the Delay method
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples” Demonstration title:, S02L04_Example_Delay. The previous slide displays code. Upon dropping the Say tile, you are prompted for the text type; select Custom TextString. Upon the value prompt, type your text.
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples”. Demonstration title: S02L04_Example_Turn_2 The object&apos;s sub-part may be selected from the Instance selector, click the arrow. Once selected, then motion may be added. 1 2 3
• A textual storyboard is an organized list of the sequential tasks that the program will execute in the animation.
• A textual storyboard is an organized list of the sequential tasks that the program will execute in the animation.
• A textual storyboard is an organized list of the sequential tasks that the program will execute in the animation.
• This lesson references example files. The example files are located in iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples” Students should now: 1. Go to iLearning Section 0 Resources section 2. From Section 2, locate and click-on the URL entitled “Section Examples” 3. Save the zip file to a location you will remember 4. Extract the files to a location you will remember.
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples”. Demonstration title: S02L04_Example_Simultaneous_1
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples”. Demonstration title: S02L04_Example_Simultaneous_1
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples”. Demonstration title: S02L04_Example_Simultaneous_1
• Find a demonstration for this exercise in the iLearning, Section 0 Course Resources section. Refer to Section 2 title “Section Examples”. Demonstration title: S02L04_Example_Simultaneous_1
• Note: The code includes establishing the camera as a vehicle to the UFO object. Adding the camera as a vehicle to an object can add a new dimension to your animations.
• Note: The code includes establishing the camera as a vehicle to the UFO object. Adding the camera as a vehicle to an object can add a new dimension to your animations.
• Experiment with students using trial and error to find the exact distance to the front of the ramp.
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• For each event, repeat steps 3 through6. This will be repeated for Down, Right and Left arrow keys. Hint: Use Turn command for right and left; and set amount to .01 Depending on your event handling, the final false (i.e., else) statement will remain empty: if user does not select a key, then nothing happens.
• For each event, repeat steps 3 through6. This will be repeated for Down, Right and Left arrow keys. Hint: Use Turn command for right and left; and set amount to .01 Depending on your event handling, the final false (i.e., else) statement will remain empty: if user does not select a key, then nothing happens.
• For each event, repeat steps 3 through6. This will be repeated for Down, Right and Left arrow keys. Hint: Use Turn command for right and left; and set amount to .01 Depending on your event handling, the final false (i.e., else) statement will remain empty: if user does not select a key, then nothing happens.
• For each event, repeat steps 3 through6. This will be repeated for Down, Right and Left arrow keys. Hint: Use Turn command for right and left; and set amount to .01 Depending on your event handling, the final false (i.e., else) statement will remain empty: if user does not select a key, then nothing happens.
• For each event, repeat steps 3 through6. This will be repeated for Down, Right and Left arrow keys. Hint: Use Turn command for right and left; and set amount to .01 Depending on your event handling, the final false (i.e., else) statement will remain empty: if user does not select a key, then nothing happens.
• The checklist is a programmer&apos;s final check to ensure their animation is its best.
• The checklist is a programmer&apos;s final check to ensure their animation is its best.
• ### Alice workshop v1_presentation_slides_v1.1

2. 2. Telling a Story Visually What Will I Learn? Objectives In this lesson, you will learn how to: • Compare and define an animation and a scenario • Write an example of using the four problem solving steps to storyboard an animation • Use functional decomposition to write a storyboard • Flowchart a storyboard • Describe an algorithm Copyright © 2012, Oracle. All rights reserved. 2
3. 3. Telling a Story Visually Problem Solving Approach to Animation A big problem, or sometimes even a little problem, is often solved by breaking down the process into parts. Functional decomposition is the process of taking a complex problem or process and breaking it down into smaller parts that are easier to manage. Examine this high level process: • Consider a math concept that requires many steps. • Identify the high level steps for the math concept. • Further refine and define the tasks needed for each high level step. • Present the problem as an animation. Copyright © 2012, Oracle. All rights reserved. 3
4. 4. Telling a Story Visually Problem Solving Approach to Animation (cont.) The process to develop an animation is very similar to the problem solving process. Compare the problem solving and animation development process listed below. Problem Solving Process Step 1: Step 2: Step 3: Step 4: Identify the Develop a Implement Test and Problem Solution the Solution Revise the Solution Animation Development Process Step 1: Step 2: Step 3: Step 4: Define the Design a Program Run the Scenario Storyboard the Animation Animation Copyright © 2012, Oracle. All rights reserved. 4
5. 5. Telling a Story Visually Animation Defined An animation is a sequence of actions that simulate movement. As the animation creator, you will program in Alice what the animation should do, and Alice will render the animation for you. Rendering is the process whereby the system converts the image frames into a seamless animation. Alice3 does all of the work necessary to render the animation based on what instructions you provided for how the objects should act. Copyright © 2012, Oracle. All rights reserved. 5
6. 6. Telling a Story Visually Step 1: Define the Scenario Step 1: Define the Scenario Professional animators begin the process by developing a scenario—or story—that gives the animation a purpose. A scenario is a story in the form of a problem to solve or task to perform. Examples • Story representing a conflict and resolution • Lesson to teach a math concept • Process to simulate or demonstrate • Game to play Copyright © 2012, Oracle. All rights reserved. 6
7. 7. Telling a Story Visually Step 1: Define the Scenario (cont.) Examples of scenarios and animations are described below. Scenario Type Scenario Animation Story A cat is stuck in a tree A man climbs up a tree and needs help getting to save the cat. down. Lesson Students have trouble A timed matching game memorizing chemistry to match chemistry symbols. symbols with their definitions. Process A demonstration of how Virtual tools to show you to change a car tire. how to change a tire on a virtual car. Game An airplane flies through An interactive game to fly the sky but should not hit an airplane around objects in its path. objects in the sky. Copyright © 2012, Oracle. All rights reserved. 7
8. 8. Telling a Story Visually Step 2: Design a Storyboard Step 2: Design a Storyboard A storyboard details each scene of your animation. It includes the following components: Component Definition Example Object A moving or non-moving Animals, cars, people, character that you position trees and/or program to move and act Scene The place (or “world” in Alice) Park, library, school, where your story occurs home Actions The instructions for how each Walk 2 meters, turn object should act in the scene left, say “Hello!” User The ways in which the user can Keyboard commands interactions manipulate the objects in the or mouse clicks to animation make objects move Design How the objects and scenery Size, position, specifications should look in the animation location, color Copyright © 2012, Oracle. All rights reserved. 8
9. 9. Telling a Story Visually Step 2: Design a Storyboard (cont.) There are two types of storyboards: • Visual – a series of illustrated images that represent the main scenes in the animation • Textual – detailed, ordered list of the actions each object performs in each scene in the animation In computing, a textual storyboard is called an algorithm: a list of actions to perform a task or solve a problem. A storyboard can be created on paper, or using digital tools such as a word processing program, paint or drawing program, or presentation program. Copyright © 2012, Oracle. All rights reserved. 9
10. 10. Telling a Story Visually Step 2: Design a Storyboard (cont.) Visual Storyboard Example Boy and girl sit on Girl notices mobile Girl says out loud park bench. Boy walks phone. She thinks, “Hey! You forgot your away and leaves his “Hey! That boy forgot phone!” Boy turns phone behind. his phone!” around and walks back to bench. He says, “Oh thank you!” Copyright © 2012, Oracle. All rights reserved. 10
11. 11. Telling a Story Visually Step 2: Design a Storyboard (cont.) Textual Storyboard Example Do in order Boy and girl sit on park bench. Boy stands up and walks away, leaving his mobile phone on the park bench. Girl turns to look at phone. Girl thinks, “Hey! That boy forgot his phone!” Girl says out loud, “Hey! You forgot your phone!” Boy stops and turns around. Boy walks back to park bench and says, “Oh thank you!” Copyright © 2012, Oracle. All rights reserved. 11
12. 12. Telling a Story Visually Step 2: Design a Storyboard (cont.) Flowchart the storyboard so that you can organize the process of the animations actions, and ensure each flows logically. True Boy leaves False phone on bench Girl says: “Hey, you Girl does nothing forgot your phone.” Boy stops and turns around. Boy keeps walking Boy comes back To bench and says “Thank you.” End Copyright © 2012, Oracle. All rights reserved. 12
13. 13. Telling a Story Visually Step 3: Step 3: Program the Animation Program the Animation After completing your visual and textual storyboards you program your animation in Alice. Your storyboard identifies the design specifications for the animation (how objects appear, move, speak, interact, etc.) Your program code provides the run-time instructions to Alice. Copyright © 2012, Oracle. All rights reserved. 13
14. 14. Telling a Story Visually Step 4: Run the Animation Step 4: Run the Animation When you finish programming your animation, you run and test the animation to ensure proper execution. This process is often referred to as testing and debugging the software. Programs are tested by entering unanticipated commands to try and “break” the code. When something is broken or doesnt work as you intended in a software program, it is often referred to as a “bug”. Debugging is the process of finding software bugs in a software program. Copyright © 2012, Oracle. All rights reserved. 14
15. 15. Telling a Story Visually Step 4: Run the Animation (cont.) Test and debug your animation frequently. Below is a list of debugging tasks you may consider: • Adjust the direction, distance, and duration that objects move. • Adjust math calculations that help refine the distance or duration that objects move. • Change procedures (instructions in the code) that do not work as intended to ones that work better. • Resolve errors created by the programmer. Copyright © 2012, Oracle. All rights reserved. 15
17. 17. Creating a Scene by Adding and Positioning Objects What Will I Learn? Objectives • Identify all components of a scene for a given scenario • Define a gallery using Java programming terminology • Define classes and instances and give examples of both • Describe the value of saving multiple versions of an animation scene • Describe three-dimensional positioning axes • Describe the difference between precise positioning and drag-and-drop positioning • Use a one-shot procedural method to precisely position an object in a scene Copyright © 2012, Oracle. All rights reserved. 17
18. 18. Creating a Scene by Adding and Positioning Objects Initial Scene To create an animation you first create an initial scene. The initial scene is the first scene in your animation where you set up your animations objects and background template. An initial scene has three components: • Template that provides the sky, ground, and light • Non-moving scenery object(s) that provide the setting • Moving object(s) that provide the action Copyright © 2012, Oracle. All rights reserved. 18
19. 19. Creating a Scene by Adding and Positioning Objects Initial Scene (cont.) Example Here are the components of an ocean floor scene. Fish are acting objects The coral is a scenery object The ocean floor is a template Copyright © 2012, Oracle. All rights reserved. 19
20. 20. Creating a Scene by Adding and Positioning Objects Develop a Scene Steps to develop an initial scene: 1. Create a new project and select a template. 2. Locate classes in the gallery. 3. Add instances of one or more classes to a scene. 4. Save the project. 5. Position the instances within the scene. Copyright © 2012, Oracle. All rights reserved. 20
21. 21. Creating a Scene by Adding and Positioning Objects Step 1: Create a New Project To set up an initial scene follow these steps: 1. Start Alice 3. 2. In the dialog box, select the Templates tab. 3. Select a template, then click OK. 4. In the File menu, select Save As... 5. Name the project. 6. Save the project. Copyright © 2012, Oracle. All rights reserved. 21
24. 24. Creating a Scene by Adding and Positioning Objects Step 2: Locate Classes After a template is selected, the code editor is displayed (the default view). Use the Setup Scene button to switch to the scene editor as it contains the tools needed to edit your scene. In the scene editor, you can: 1. Select objects to add to the scene from the gallery 2. Position objects in the scene using the Handles palette 3. Edit an objects properties using the Properties panel 4. Run (“play”) the animation 5. Access the Code editor Copyright © 2012, Oracle. All rights reserved. 24
25. 25. Creating a Scene by Adding and Positioning Objects Step 2: Locate Classes (cont.) This is an example display of the Scene Editor. 4 2 3 5 1 Copyright © 2012, Oracle. All rights reserved. 25
26. 26. Creating a Scene by Adding and Positioning Objects Step 2: Locate Classes (cont.) A gallery of classes is available with many objects you can add to your scene. You can browse folders or search by keyword. The gallery is a collection of 3D models that can be inserted into the scene. Copyright © 2012, Oracle. All rights reserved. 26
27. 27. Creating a Scene by Adding and Positioning Objects Step 2: Locate Classes (cont.) Within a class folder in the gallery, select the specific class you want to add to the scene. A class contains the specifications that define the appearance and movement of a 3D object, such as a frog, cat, or tree. Instructions are provided to Alice3 for how to create and display an object from that class in your scene. Classes are grouped into folders, such as Animals, People, City, etc. All objects within a class have common properties, such as appearance and movement. Copyright © 2012, Oracle. All rights reserved. 27
28. 28. Creating a Scene by Adding and Positioning Objects Step 2: Locate Classes (cont.) Example A class could be a type of bird, such as a chicken. Every time a chicken is added to a scene, it has the same basic properties of the chicken class: two legs, two wings, feathers, and the ability to fly. Copyright © 2012, Oracle. All rights reserved. 28
30. 30. Creating a Scene by Adding and Positioning Objects Step 3: Add Instances (cont.) Select the chicken class from the gallery. Use the mouse to drag the object to the scene. The object becomes an instance of the Chicken class. Now, you can modify its properties and program the chicken instance to perform tasks. Chicken Instance of Class Chicken Copyright © 2012, Oracle. All rights reserved. 30
31. 31. Creating a Scene by Adding and Positioning Objects Step 3: Add Instances (cont.) With an instance, you can: • Use all of the properties in its class • Change its properties • Program it to perform new tasks • Save it to use in other projects Copyright © 2012, Oracle. All rights reserved. 31
32. 32. Creating a Scene by Adding and Positioning Objects Step 3: Add Instances (cont.) When you add an instance to the scene you can accept the default name provided by Alice or specify a new instance name. Providing unique instance names will help you to assign actions to the correct objects in the scene. Alice preferences can be set to automatically name instances of the same class with an incremental number. Copyright © 2012, Oracle. All rights reserved. 32
33. 33. Creating a Scene by Adding and Positioning Objects Step 4: Save the Project Save projects frequently at various points throughout your animation development. Alice 3 will remind you to save your project. To save a project: 1. Select File 2. Select Save As... 3. Select the location to save the project (e.g., computer, file server, memory stick) 4. Enter project name 5. Click Save Copyright © 2012, Oracle. All rights reserved. 33
34. 34. Creating a Scene by Adding and Positioning Objects Step 4: Save the Project (cont.) If you want to use the same scene to create several different animations, save multiple versions of the project at different points of development, giving the versions different names. By using a saved version of a scene to create a new animation, you save time already spent creating and positioning objects in the scene, and can go straight to programming the instructions for how objects should move and interact. Copyright © 2012, Oracle. All rights reserved. 34
35. 35. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects Once instances are added to a scene, you need to position them how you want them to appear when the animation starts. This includes: • Direction the object should face • The objects orientation relative to other objects in the scene • The objects position • The position of the objects sub-parts (arms, legs, head) Copyright © 2012, Oracle. All rights reserved. 35
36. 36. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects (cont.) All objects: • Have 3D coordinates on an x, y, and z axis • Have a center point, where its own axes intersect (usually at the center of their mass) • Have sub-parts that can move • Move relative to their center point • Can be positioned by moving the axes Copyright © 2012, Oracle. All rights reserved. 36
37. 37. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects (cont.) Objects move relative to their own orientation, or sense of direction. Example An object facing backward, programmed to move forward 2 meters, moves 2 meters towards the back of the scene. Copyright © 2012, Oracle. All rights reserved. 37
38. 38. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects (cont.) Ways to position an object: 1. Imprecise: 1. “Drag and drop” with cursor 2. Precise: 1. Enter values for the x, y, and z coordinates or 2. Use a procedural method Copyright © 2012, Oracle. All rights reserved. 38
39. 39. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects (cont.) To position using a “drag and drop” method: 1. Select the object, or sub-part of object, with the cursor 2. Select a handle style 3. Position object with cursor (rings that surround the object may be used to manipulate the object) Handle Type Description Default Simple rotation and movement Rotation Rotate about the x, y, and z axes Movement Move along the x, y, and z axes Resize Change size of the object and stretch it along the x, y, and z axes Copyright © 2012, Oracle. All rights reserved. 39
41. 41. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects (cont.) You can use the four handle styles to position an objects sub- parts as well. Select the instance, then its sub-part. Use the rings around the subpart to position it. Copyright © 2012, Oracle. All rights reserved. 41
42. 42. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects (cont.) To position by entering coordinate values: 1. In the Properties panel, locate the Position property. 2. Enter values in the x, y, and z axes. 3. The object will automatically re-position to the coordinates. Copyright © 2012, Oracle. All rights reserved. 42
43. 43. Creating a Scene by Adding and Positioning Objects Step 5: Position Objects (cont.) To position using a one-shot procedure: 1. Right click on the object in the scene editor. 2. Select Procedures. 3. Select the procedure. 4. Enter the argument values. 5. The object will automatically move based on the procedure and arguments selected. A procedure is a set of instructions, or programmed code, for how the object should perform a task. Note that one-shot procedures are used to make a scene adjustment. The procedure does not execute when the Run button is executed. Copyright © 2012, Oracle. All rights reserved. 43
45. 45. Using Procedures What Will I Learn? Objectives • Toggle and describe the visual difference between the scene editor and code editor • Correlate storyboard statements with program execution tasks • Identify the correct procedure to move an object in a scene • Use procedures to move objects in a scene • Add Java programming procedures to the code editor • Demonstrate how procedure values can be altered • Add a control statement to the code editor • Use random numbers to randomize motion Copyright © 2012, Oracle. All rights reserved. 45
46. 46. Using Procedures Prepare to Program To prepare to program, use a top-down development approach: 1. Define the high-level scenario for the animation. 2. Document the actions that take place in the scenario, step-by-step, in a textual storyboard. Doing this helps you gain a thorough understanding of all of the actions that need to occur in the animation. 3. Create a table where you match the storyboard steps to the exact instructions that you need to program in Alice 3. 4. Review the table at several points during the animations development to ensure you are creating it correctly and on-track to completion. Revise the table as necessary throughout the animations development. Copyright © 2012, Oracle. All rights reserved. 46
47. 47. Using Procedures Prepare to Program (cont.) Review this example textual storyboard: Do the following steps in order Chicken walks by Cat turns to look at Chicken Cat says, “Dinner time!” Chicken says, “Oh no!” Chicken turns to right Do the following steps together Chicken walks away quickly Cat walks away quickly Copyright © 2012, Oracle. All rights reserved. 47
48. 48. Using Procedures Prepare to Program (cont.) Create a table to match the storyboard actions to the programming instructions needed for the animation. Storyboard Action Program Instructions Order of Instructions Do in order Chicken walks by Chicken moves forward 2 meters Cat looks at chicken Cat turns to face chicken Cat says, “Dinner time!” Cat says “Dinner Time!” Chicken says, “Oh no!” Chicken says “Oh no!” Chicken and cat turn right Chicken turns right .5 meters Cat turns right .125 meters Cat chases Chicken Chicken move forward 2 meters Do together Cat move forward 2 meters Copyright © 2012, Oracle. All rights reserved. 48
49. 49. Using Procedures Prepare to Program (cont.) Note that the object being programmed changes. Ensure that the correct object is selected when choosing a programming instruction. Storyboard Action Program Instructions Order of Instructions Do in order Chicken walks by Chicken moves forward 2 meters Cat looks at chicken Cat turns to face chicken Cat says, “Dinner time!” Cat says “Dinner Time!” Chicken says, “Oh no!” Chicken says “Oh no!” Chicken and cat turn right Chicken turns right .5 meters Cat turns right .125 meters Cat chases Chicken Chicken move forward 2 meters Do together Cat move forward 2 meters Copyright © 2012, Oracle. All rights reserved. 49
50. 50. Using Procedures Prepare to Program (cont.) Consider grouping the programming instructions together logically and inserting comments into your program to help organize your programing tasks. //chicken and cat movement Chicken walks by Chicken moves forward 2 meters Cat looks at chicken Cat turns to face chicken //chicken and cat speaking Cat says, “Dinner time!” Cat says “Dinner Time!” Chicken says, “Oh no!” Chicken says “Oh no!” //chicken and cat movement away Chicken and cat turn right Chicken turns right .5 meters Cat turns right .125 meters Cat chases Chicken Chicken move forward 2 meters Cat move forward 2 meters Copyright © 2012, Oracle. All rights reserved. 50
51. 51. Using Procedures Prepare to Program (cont.) Once the objects are added to the scene in the scene editor, you can use “one-shot” procedures to precisely position them for the initial scene, or starting point, of your animation. When positioning objects in a scene, a “one-shot” procedure is a piece of program code that is executed once to define a single movement for an object in the scene editor. Alice 3 has a set of these procedures available for each class. Copyright © 2012, Oracle. All rights reserved. 51
52. 52. Using Procedures Prepare to Program (cont.) To call a one-shot procedure for an object, right-click on the object, select the procedure from the drop-down list, and specify the procedure arguments. The object will immediately move based on what you specified. Copyright © 2012, Oracle. All rights reserved. 52
53. 53. Using Procedures Writing the Animation Program Once you have positioned the objects and are ready to write the animation program, from Scene View, click Edit Code to display the code editor. Copyright © 2012, Oracle. All rights reserved. 53
54. 54. Using Procedures Writing the Animation Program (cont.) A scene can have multiple actors. Always make sure you are creating a programming instruction for the correct actor. Just below the scene view window in the code editor, there is an instance pull down menu. Use the instance pull down menu to select the actor, or object, for which you want to specify a programming instruction. Copyright © 2012, Oracle. All rights reserved. 54
55. 55. Using Procedures Writing the Animation Program (cont.) For example, if you have a pajama fish and a clown fish in your scene, and you want the pajama fish to move forward choose the pajama fish in the instance menu before creating the programming step to move forward. Copyright © 2012, Oracle. All rights reserved. 55
56. 56. Using Procedures Writing the Animation Program (cont.) To create a programming instruction for a specific object, click and drag the programming instruction into the myFirstMethod area of the code editor. Copyright © 2012, Oracle. All rights reserved. 56
57. 57. Using Procedures Writing the Animation Program (cont.) Below the instance pull down menu is the Methods Panel containing three tabs that organize the Procedures, Functions, and Properties for the object selected in the instance pull down menu: • Procedures tab: initially displays all of the pre-defined procedures for an object. • Functions tab: displays all of the pre-defined functions for an object. Switch between the • Properties tab: displays all of tabs in the Methods the properties of an object. Panel to select a procedure, function, or object property. Copyright © 2012, Oracle. All rights reserved. 57
58. 58. Using Procedures Programming Statements The Procedures tab: • Displays a pre-defined set for each class • Displays procedures declared for the class Procedure examples: • Move • Turn • Roll A procedure is a piece of program code that defines how the object should execute a task. Alice 3 has a set of procedures for each class, however, users can create (“declare”) new procedures. Copyright © 2012, Oracle. All rights reserved. 58
59. 59. Using Procedures Programming Arguments There are two components that follow the name of the object in a programming statement: • Procedure name • Procedure arguments Programming arguments initially display with ??? to indicate the location at which the argument will be placed. Procedure Arguments Copyright © 2012, Oracle. All rights reserved. 59
60. 60. Using Procedures Programming Arguments (cont.) Arguments are selected after the procedure is dragged into the code editor using cascading menus. Argument types can include: • Direction • Amount • Duration • Target • Text An argument describes how to perform the procedure. Copyright © 2012, Oracle. All rights reserved. 60
61. 61. Using Procedures Programing Arguments (cont.) Use the menus to select the appropriate argument for a procedure. You may need to simply select a placeholder argument that can be changed later. Copyright © 2012, Oracle. All rights reserved. 61
62. 62. Using Procedures Programming Arguments (cont.) To change an argument use the menu accessed by clicking the down pointing arrow to the right of the argument value. Select the applicable option from the argument list. Copyright © 2012, Oracle. All rights reserved. 62
64. 64. Using Procedures Object Direction An object can move in six directions: • Up • Down • Forward • Backward • Right • Left Object direction is egocentric. For example, if an object is facing you, and you specify an instruction for the object to turn left, the object will turn to it’s left, not to your left. Copyright © 2012, Oracle. All rights reserved. 64
65. 65. Using Procedures Move Procedure The move procedure moves the object in all six directions. You select the direction and distance to move. Copyright © 2012, Oracle. All rights reserved. 65
66. 66. Using Procedures Move Toward Procedure The move toward procedure moves the object toward another object. You select the object to move, the object to move toward and the distance the object will move. Copyright © 2012, Oracle. All rights reserved. 66
67. 67. Using Procedures Move Away From Procedure The move away from procedure moves the object away from another object. You select the object to move away from, and the distance to move. Copyright © 2012, Oracle. All rights reserved. 67
68. 68. Using Procedures Move To Procedure The move to procedure will move an object the distance to the center of the target object. You select the object to move to, and the program calculates the distance for you. You may want to use additional procedures to adjust the position of the moving object so it does not stay in the center of the other object. Copyright © 2012, Oracle. All rights reserved. 68
69. 69. Using Procedures Move and Orient To Procedure The move and orient to procedure will move an object the distance to the center of the target object. Additionally, it adjusts the moving objects orientation to match the orientation of the target object. You select the object to move to, and the program calculates the distance for you as well as adjusts the objects orientation. Copyright © 2012, Oracle. All rights reserved. 69
70. 70. Using Procedures Delay Procedure The Delay procedure will halt an object for a specific number of seconds. You select the number of seconds to delay until the next procedure is executed. In this example, the clock delays one second, then the hour hand on the clock rolls to the left 0.25 meters. Copyright © 2012, Oracle. All rights reserved. 70
71. 71. Using Procedures Say Procedure The Say procedure will create a call out bubble with text to make an object appear to talk. You can use the pre-defined text or choose to annotate your own text. Copyright © 2012, Oracle. All rights reserved. 71
72. 72. Using Procedures Rotation Procedures There are two procedures for rotating objects: • Turn • Roll The turn procedure rotates objects on their center point: • Left • Right • Forward • Backward The roll procedure rolls objects on their center point: • Left • Right Copyright © 2012, Oracle. All rights reserved. 72
73. 73. Using Procedures Turn and Roll Procedures Compared The object below rotates (turns) on its center point, right and left. Stationary Right Turn Left Turn The object below rotates (rolls) on its center point, right and left. Stationary Right Roll Left Roll Copyright © 2012, Oracle. All rights reserved. 73
74. 74. Using Procedures Roll Procedure Example Roll Right and Left Example: Some objects have sub-parts that are also movable. In this example, the pocket-watch object has hour and minute hand sub-parts. The sub-parts may be animated to roll on the clocks center point. Copyright © 2012, Oracle. All rights reserved. 74
75. 75. Using Procedures Examining Sub-part Rotation Rotation can be applied to an entire object, or select parts (“sub-parts”) of the object. Above, the objects sub-part (its head) displays rings; the rings show the sub-parts range of motion. Copyright © 2012, Oracle. All rights reserved. 75
76. 76. Using Procedures Edit Programming Statements You use the drag-and-drop method to bring procedures into the code editor. You can reorder your objects using drag- and-drop also. There is a dotted area to the left of the object name. Use this dotted area to drag-and-drop without changing an arguments value. Copyright © 2012, Oracle. All rights reserved. 76
78. 78. Using Procedures Control Statements Procedures listed in the code editor will execute sequentially unless instructions are given to the program to execute in a different manner. These instructions are referred to as control statements. Control statements define how to execute a sequence of programming statements in a manner other than sequentially. Examples: • Do in order: Execute statements in sequential order; referred to as “sequential control” • Do together: Execute statements simultaneously • Count: Execute statements a specific number of times • While: Execute while a condition is true Copyright © 2012, Oracle. All rights reserved. 78
79. 79. Using Procedures Control Statements (cont.) Control statement tiles are located below the programming statements you have entered into the code editor. You can enter control statements before or after programming statements are entered into the code editor. Example 1: you can enter programming statements into the code editor, run the program, and then determine you want two procedures to execute at the same time. You can then drag a do together control statement into your code editor and move the two procedures into the control statement. Example 2: you can pre-determine that you want two programming statements to execute simultaneously. You can drag a do together control statement into your code editor and then create the two procedures within the control statement. Copyright © 2012, Oracle. All rights reserved. 79
82. 82. Using Procedures Step 3: Enter Procedure Drag the first procedure into the control statement in the code editor. Copyright © 2012, Oracle. All rights reserved. 82
83. 83. Using Procedures Step 4: Select Argument Values Select the values for the arguments to create the complete programming statement. Test as necessary. Copyright © 2012, Oracle. All rights reserved. 83
84. 84. Using Procedures Step 5: Repeat Steps 1-4 Repeat steps 1-4 until all of the programming statements are entered into the control statement. Copyright © 2012, Oracle. All rights reserved. 84
86. 86. Using Procedures Step 7: Edit Programming Statements It may take several attempts to get the animation to work as desired. Edit programming arguments as necessary. These steps are often referred to as testing and debugging. Copyright © 2012, Oracle. All rights reserved. 86
87. 87. Using Procedures Debug the Animation You may run your animation many times, making adjustments to the arguments after each execution. This refinement is referred to as debugging and testing. Be sure to save often while debugging your program. Copyright © 2012, Oracle. All rights reserved. 87
88. 88. Using Procedures Random Numbers Random numbers are a sequence of numbers generated by the computer with no pattern in their sequence. For example: • 15674 • -6934022.1133 • 03 Computers require random number generation for: • Security: Randomly generated passwords • Simulation: Earth science modeling (e.g., erosion over time) Copyright © 2012, Oracle. All rights reserved. 88
89. 89. Using Procedures Random Numbers (cont.) In the real world, animals do not move in straight geometric lines. They change direction, even if slightly, as they walk, swim and fly. Random numbers may be utilized in the distance argument of a procedure, so that an object moves in a less predictable manner that appears more lifelike. Examples: The floating motion of a fish The flying motion of a bird Copyright © 2012, Oracle. All rights reserved. 89
90. 90. Using Procedures Random Numbers (cont.) When you use random numbers you specify a low and high value for the range of numbers from which to pull a randomized number. Examine the example below. An up and down move procedure has been established for the clownFish. You replace the placeholder value with the Random option. Copyright © 2012, Oracle. All rights reserved. 90
91. 91. Using Procedures Random Numbers (cont.) You choose the argument containing the ??? placeholders. NextRandomRealNumberInRange Then you specify the values desired from the list of available values or by specifying a custom decimal Custom Decimal Number number for each range value. Copyright © 2012, Oracle. All rights reserved. 91
93. 93. Using Procedures Random Numbers (cont.) When the animation is run, the fish will move a random amount up and down. Copyright © 2012, Oracle. All rights reserved. 93
95. 95. Declaring Procedures What Will I Learn? Objectives • Describe inheritance and how traits are passed from superclasses to subclasses • Describe when to implement procedural abstraction • Demonstrate how to declare a procedure • Identify and use procedural abstraction techniques to simplify animation development Copyright © 2012, Oracle. All rights reserved. 95
96. 96. Declaring Procedures Inheritance A dalmatian is a type of dog. When a dalmatian puppy is born, Dog Class (Superclass) it inherits two types of characteristics: • All of the characteristics of the dog class (or “superclass”), including four legs, two eyes, fur, and the Dalmatian Class ability to bark. (Subclass) • All of the characteristics of the dalmatian dog class (the “subclass”, which is a subset of the dog class), including white fur, black spots, etc. Copyright © 2012, Oracle. All rights reserved. 96
97. 97. Declaring Procedures Inheritance (cont.) Just like animals, objects inherit the characteristics of their class, including all of the classs procedures. Inheritance means that each subclass inherits the methods and properties of its superclass. When a dalmatian object is created, it inherits a set of procedures, functions, and properties from the Quadruped class and Dalmatian subclass that you can view in the code editor. Copyright © 2012, Oracle. All rights reserved. 97
98. 98. Declaring Procedures Inheritance (cont.) Click on the class hierarchy drop-down menu in the code editor to view the list of classes and subclasses in your animation. Select a class to view its inherited procedures and other properties. Copyright © 2012, Oracle. All rights reserved. 98
99. 99. Declaring Procedures Procedural Abstraction An object, or several objects, may perform the same repetitive motions. For example, a school of five fish may swim together. It takes a lot of procedures to program this swim movement for each fish, and takes up a lot of space in myFirstMethod. Copyright © 2012, Oracle. All rights reserved. 99
100. 100. Declaring Procedures Procedural Abstraction (cont.) Sometimes, default procedures needed to perform an action are not available for an object. For example, a bird may need to fly, but there is no default fly method available for bird objects. Many procedures are required to accomplish this action, which takes up a lot of space in myFirstMethod. Copyright © 2012, Oracle. All rights reserved. 100
101. 101. Declaring Procedures Procedural Abstraction (cont.) Review existing code or the textual storyboard to identify and plan procedures to declare in your program. Separating out motions into their own procedures can: • Simplify code and make it easier to read • Allow many objects of a class to use the same procedure • Allow subclasses of a superclass to use the procedure Procedural abstraction is the concept of making code easier to understand and reuse. An example of this is to remove repetitive or lengthy programming statements from myFirstMethod and put them in their own procedures to make the code easier to read, understand, and reuse by multiple objects, and in some cases, multiple classes. Copyright © 2012, Oracle. All rights reserved. 101
102. 102. Declaring Procedures Procedural Abstraction (cont.) To identify which parts of code could benefit from declaring a procedure, look for the following: • Motions that do not have a default procedure, such as a bird flying. This requires programming it to flap its wings repeatedly while simultaneously moving forward. • Motions that need to be used by multiple objects or classes, such as all quadrupeds in the animation needing to know how to hop up and down. • Singular motions that require many programming statements that take up a lot of room in myFirstMethod, such as a person moving many body parts to walk. Moving these procedures into their own “walk” procedure would overall make the code easier to read. Copyright © 2012, Oracle. All rights reserved. 102
103. 103. Declaring Procedures Procedural Abstraction Example 1 In the following storyboard, the bird flies by turning its shoulders and moving forward simultaneously. This repetitive motion could be extracted into its own flying procedure. Do together Do together Bird turns right shoulder backward Bird flies Bird turns left shoulder backward Bird moves forward Bird moves forward ... Do together Bird turns right shoulder forward Bird turns left shoulder forward Bird moves forward ... Copyright © 2012, Oracle. All rights reserved. 103
104. 104. Declaring Procedures Procedural Abstraction Example 2 In the following code, each bunny moves up and down in order to simulate a hopping motion. This repetitive motion that needs to be used by all bunny objects could be pulled into its own hop procedure. Copyright © 2012, Oracle. All rights reserved. 104
105. 105. Declaring Procedures Default Features of Code Editor The code editor has several default features that are important to understand when declaring a procedure. The myFirstMethod tab is displayed by default when the code editor is opened. Copyright © 2012, Oracle. All rights reserved. 105
106. 106. Declaring Procedures Default Features of Code Editor (cont.) By default, the MyScene class tab is displayed, which sets up the initial scene and the objects in it. The MyScene tab represents the MyScene class which calls the myFirstMethod when the Run button is selected. Copyright © 2012, Oracle. All rights reserved. 106
108. 108. Declaring Procedures Class Hierarchy Menu (cont.) Remember the role that inheritance plays in procedures. Selecting a superclass, such as MySwimmer, allows you to declare a procedure that can be used by all MySwimmer subclasses, such as MyClownFish. Copyright © 2012, Oracle. All rights reserved. 108
109. 109. Declaring Procedures Declare A Procedure To declare a procedure: 1. Select the class that should inherit the procedure from the class hierarchy. Remember that all subclasses beneath the class will inherit the procedure as well (subclasses indicated by a + or ++ next to the class name). Copyright © 2012, Oracle. All rights reserved. 109
112. 112. Declaring Procedures Declare A Procedure (cont.) 4. A new tab will open with the name of the procedure. This is where the new procedure will be coded. Copyright © 2012, Oracle. All rights reserved. 112
113. 113. Declaring Procedures Add Procedure to myFirstMethod As you code the procedure, you will debug it often. A helpful tip is to add the new procedure to myFirstMethod before coding. Then, you can click the Run button to test the procedure as you code it. To add the procedure to myFirstMethod: 1. Click the Back to MyScene button. Copyright © 2012, Oracle. All rights reserved. 113
116. 116. Declaring Procedures Add Procedure to myFirstMethod (cont.) 4. In the Procedures tab, locate the declared procedure. The instance inherited this procedure from the MySwimmer superclass. 5. Drag the procedure into myFirstMethod. Copyright © 2012, Oracle. All rights reserved. 116
117. 117. Declaring Procedures Edit Declared Procedures Once the procedure is declared, you can add programming statements to it, and edit as necessary. To edit the declared procedure: 1. Select the class where the procedure was declared from the class hierarchy drop-down menu. Copyright © 2012, Oracle. All rights reserved. 117
119. 119. Declaring Procedures Edit Declared Procedures (cont.) 3. Create or edit the code in the procedure. 4. Click the Run button to test. Debug as necessary. Copyright © 2012, Oracle. All rights reserved. 119
121. 121. Declaring Procedures Edit Declared Procedures (cont.) Continue to code the animation. Edit the animations code and declared procedures, and create additional procedures, as necessary. Copyright © 2012, Oracle. All rights reserved. 121
122. 122. Declaring Procedures Identify Opportunities for Declared Procedures As you code, continue to identify where you could implement procedural abstraction techniques to declare procedures. In the code below, the fish needs to bob up and down. A separate “bob” procedure could be declared. Copyright © 2012, Oracle. All rights reserved. 122
124. 124. Using Control Statements and Functions What Will I Learn? Objectives • Define multiple control statements to control animation timing • Create an animation that uses a control statement to control animation timing • Recognize programming constructs to invoke simultaneous movement • Use functions to control movement based on a return value • Create programming comments Copyright © 2012, Oracle. All rights reserved. 124
125. 125. Using Control Statements and Functions Editing Arguments When a procedure tile is dropped into the code editor, its arguments may be changed, or further defined, to control the objects movement and timing. Procedure Object Direction Amount Duration A computer program requires arguments to tell it how to implement the procedure. Examples of Alice 3 arguments are: object, direction, direction amount, and time duration. Copyright © 2012, Oracle. All rights reserved. 125
126. 126. Using Control Statements and Functions Editing Arguments (cont.) Use the arrows next to the arguments value to display the menu and select a new value. Copyright © 2012, Oracle. All rights reserved. 126
127. 127. Using Control Statements and Functions Editing Arguments (cont.) In the Instance menu, you can select or change the object to program. The Methods Panel will display all of the available options for the object. You can also select the arrow next to the objects name to select a sub- part, if it has any. Copyright © 2012, Oracle. All rights reserved. 127
128. 128. Using Control Statements and Functions Simultaneous Movements Do In Order is the default sequential control statement in the code editor. This statement executes procedures in sequential order. For example: • Object turns right, then • Object turns left, then • Object rolls right However, sometimes objects (and their sub-parts) need to move together at the same time, such as for walking or sitting motions, which requires the Do Together control statement. Copyright © 2012, Oracle. All rights reserved. 128
129. 129. Using Control Statements and Functions Simultaneous Movements (cont.) To create the walking motion with a bi-pedal object, a series of procedures and Do Together control statements are required. Each bipedal object may walk a little differently and require different coding to walk properly. Practice walking forward slowly. How do the subparts of each of your legs move as you walk forward? You can document this in a textual storyboard. Copyright © 2012, Oracle. All rights reserved. 129
130. 130. Using Control Statements and Functions Simultaneous Movements (cont.) Textual Storyboard for Walking Motion Left hip turns forward Do Together Whole body moves forward Left hip turns backward Right hip turns forward Left shoulder turns left Right shoulder turns right Do Together Whole body moves forward Left hip turns forward Right hip turns backward Left shoulder turns right Right shoulder turns left ... Copyright © 2012, Oracle. All rights reserved. 130
131. 131. Using Control Statements and Functions Simultaneous Movements (cont.) To program the walking motion for a person: 1. Drag the Do Together tile into the code editor. 2. Insert the procedures into the Do Together. Copyright © 2012, Oracle. All rights reserved. 131
133. 133. Using Control Statements and Functions Vehicle Property Another type of simultaneous movement is to have one object act as a vehicle of another. This means that the two objects are synchronized and move together. Examples of this relationship: • A dog walks alongside a person • A person rides a camel or horse • A camera follows around a helicopter to shoot the scene from the helicopters point of view When one object is set as a vehicle of another using the setVehicle procedure, if you program the vehicle object to move, the rider object will automatically move with it. Copyright © 2012, Oracle. All rights reserved. 133
134. 134. Using Control Statements and Functions Vehicle Property (cont.) Examples The child is positioned on the camel. Then, the camel is set as the vehicle of the child. When the camel is programmed to move, the child will stay on top and move with the camel. Copyright © 2012, Oracle. All rights reserved. 134
135. 135. Using Control Statements and Functions Vehicle Property (cont.) Examples (cont.) The helicopter is set as the vehicle of the camera. When the helicopter moves around the scene, the camera films the scene from the helicopters perspective. Copyright © 2012, Oracle. All rights reserved. 135
136. 136. Using Control Statements and Functions Vehicle Property (cont.) To assign an object as a vehicle of another object: 1. Determine the vehicle and the rider. Rider Vehicle 2. Select the rider object with your cursor. Copyright © 2012, Oracle. All rights reserved. 136
137. 137. Using Control Statements and Functions Vehicle Property (cont.) 3. From Procedures tab in the Methods Panel, drag the setVehicle programming instruction into the code editor. 4. Select the vehicle object from the menu. Copyright © 2012, Oracle. All rights reserved. 137
138. 138. Using Control Statements and Functions Vehicle Property (cont.) 5. Insert the procedures to make the vehicle move. The rider will move along with the vehicle. Copyright © 2012, Oracle. All rights reserved. 138
139. 139. Using Control Statements and Functions Vehicle Property (cont.) If at some point during the animation you want the rider to no longer be connected with the vehicle: 1. Drag another setVehicle procedure into the code editor at the point the rider should get off the vehicle. 2. Set the vehicle to this (you are setting the vehicle of the rider back to the scene). 3. Continue programming your animation. Copyright © 2012, Oracle. All rights reserved. 139
140. 140. Using Control Statements and Functions Functions Programming an objects motion requires precision: very specific instructions to ensure the object acts exactly as you intend. Precision may be achieved using trial-and-error. For example, you may continuously adjust the distance that the dog moves to the tree, and test the procedure over and over, until it moves and stands perfectly next to the tree. However, there is an easier way to program the distance that an object moves. Alice 3 provides functions that can provide information about an object, such as its depth, the direction it is facing, or its distance to another object. Copyright © 2012, Oracle. All rights reserved. 140
141. 141. Using Control Statements and Functions Functions (cont.) Functions answer questions about an object, such as its height, width, depth, and even its distance to another object. Functions provide precise answers to questions, such as: • What is the distance between the helicopter and the ground? • What is the height of the cat? • What is the width of the owl? Copyright © 2012, Oracle. All rights reserved. 141
142. 142. Using Control Statements and Functions Functions (cont.) Functions for an object can be found in the Methods Panel by selecting the Functions tab. View each objects functions in the code editor by selecting the object from the instance menu, then selecting the Functions tab. To use a function, select and drag a function tile onto an argument of an existing procedure in the code editor. Copyright © 2012, Oracle. All rights reserved. 142
143. 143. Using Control Statements and Functions Functions (cont.) For example, we want the lion to move directly to the rock without having to manually determine the distance between the lion and the rock. Steps: 1. Identify the moving object and the target object. Select the moving object from the instance menu. Copyright © 2012, Oracle. All rights reserved. 143
144. 144. Using Control Statements and Functions Functions (cont.) Steps (cont.): 2. Drag the move procedure into the code editor. 3. Select any placeholder arguments for direction and distance (the distance value will be changed in the next step). 4. From the Functions tab, drag the getDistanceTo tile onto the highlighted distance value. Copyright © 2012, Oracle. All rights reserved. 144
145. 145. Using Control Statements and Functions Functions (cont.) Steps (cont.): 5. Select the target object. To verbalize this procedure you can say “the lioness will move forward to the rock the distance amount determined by the getDistance function.” Copyright © 2012, Oracle. All rights reserved. 145
146. 146. Using Control Statements and Functions Functions (cont.) Steps (cont.): 6. Click the Run button. Notice the lion moves to the center of the rock at run-time. Copyright © 2012, Oracle. All rights reserved. 146
147. 147. Using Control Statements and Functions Functions (cont.) The lion should land near the rock, but not in the center of it. To avoid the collision, you can use math operators to reduce the distance from the moving object to the target object. To verbalize this example you can say “the lioness will move forward to the rock (Z) the distance amount determined by the getDistance function (X) minus the amount determined by calculating the width of the rock (Y) divided in half.” Lioness Rock X = Get Distance Lioness to Rock Y = Get Width of Rock Z = X – (Y / 2 ) Copyright © 2012, Oracle. All rights reserved. 147
148. 148. Using Control Statements and Functions Functions (cont.) Steps: 1. Click the outer arrow next to the function argument. 2. Select Math. Copyright © 2012, Oracle. All rights reserved. 148
149. 149. Using Control Statements and Functions Functions (cont.) Steps (cont.): 3. Select the getDistanceTo subtraction option containing the placeholder ??? symbols. 4. Select the distance amount for the placeholder. 5. Run the animation to test the distance the object moves at run-time. Copyright © 2012, Oracle. All rights reserved. 149
150. 150. Using Control Statements and Functions Functions (cont.) A precise way to avoid a collision is to remove the length of the moving object from the function. Lion moves forward Rock Lion Lion Depth Distance from lion to rock Copyright © 2012, Oracle. All rights reserved. 150
151. 151. Using Control Statements and Functions Functions (cont.) To remove the length of the moving object from the function: 1. Drag the moving objects getDepth function onto the highlighted distance value. 2. Run the animation to test the complete programming statement. Adjust with additional math calculations if necessary. Copyright © 2012, Oracle. All rights reserved. 151
152. 152. Using Control Statements and Functions Comments Remember to include comments above each segment of programming statements. Comments: • Help humans understand what your program does • Describe the intentions of the programming instructions • Do not affect the functionality or behavior of instances Copyright © 2012, Oracle. All rights reserved. 152
153. 153. Using Control Statements and Functions Comments Steps Reviewed To enter comments: 1. Drag and drop the comments tile above a code segment 2. Write comments that describe the sequence of actions in the code segment In large programs it is not uncommon to create segment comments before creating programming instructions. Copyright © 2012, Oracle. All rights reserved. 153
155. 155. Using the IF and WHILE Control Statements What Will I Learn? Objectives In this lesson, you will learn how to: • Use the IF control statement to effect execution of instructions • Use the WHILE control statement to create a conditional loop for repetitive behavior Copyright © 2012, Oracle. All rights reserved. 155
156. 156. Using the IF and WHILE Control Statements Control Statements Control statements are pre-defined statements that determine the order of execution for instructions. For example: • Do In Order, where procedures are executed sequentially • Do Together, where procedures are executed simultaneously Copyright © 2012, Oracle. All rights reserved. 156
157. 157. Using the IF and WHILE Control Statements Control Statements Nested Control statements may be nested, meaning that one or many are embedded within another. Copyright © 2012, Oracle. All rights reserved. 157
158. 158. Using the IF and WHILE Control Statements Control Statements IF and WHILE Additional control statements are: • IF control statement – A statement executes, or does not execute, dependent on the result of a condition – Also known as “conditional execution” • WHILE control statement – A statement, or block of statements, are run repeatedly – Also known as “repetition” Copyright © 2012, Oracle. All rights reserved. 158
159. 159. Using the IF and WHILE Control Statements IF Statement If it rains today, then I will wear a rain coat. Otherwise, I will wear a sweater. The above may appear to be a simple decision, but to a programmer this is a decision based on a condition. Lets interpret this condition as a process flow. A process flow is a graphical representation of a process model. Process flows use shapes to represent the actions in the model. Copyright © 2012, Oracle. All rights reserved. 159
160. 160. Using the IF and WHILE Control Statements IF Statement Flowchart If it rains today, then I will wear a rain coat. Otherwise, I will wear a sweater. If it rains today, then True False Do this: Otherwise, do this: Wear rain coat Wear sweater End Copyright © 2012, Oracle. All rights reserved. 160
161. 161. Using the IF and WHILE Control Statements IF Statement Flowchart (cont.) To apply the process flow to Alice 3 consider the following: If the mysterious, invisible cheshire cat walks into the dog, then the cheshire cat appears and says “Excuse me!”; otherwise, the cheshire cat continues walking. If cat collides True with dog False then Do this: Otherwise, do this: Cat appears and says, cat continues to walk “Excuse me!” and be invisible End Copyright © 2012, Oracle. All rights reserved. 161
162. 162. Using the IF and WHILE Control Statements IF Statement Flowchart (cont.) The important factor to consider when using the IF construct in Alice is that you must specify a true or false value for the IF construct when you first drag the tile to the code editor. You can choose either argument as a placeholder because you will change the value to be an actual statement. Consider this portion of the example: If the mysterious, invisible cheshire cat walks into the dog.... You create an IF construct and choose the true placeholder value. You then replace the true value with a programming statement that determines if the collision between the cat and the dog did in fact occur. If the collision does occur then the IF value is true and the IF statements are executed. Otherwise the Else statements are executed. Copyright © 2012, Oracle. All rights reserved. 162
163. 163. Using the IF and WHILE Control Statements Creating an IF Statement Steps to use the IF statement include: 1. Insert the initial motions that happen before the collision. In this example: 1. The cat is invisible (set opacity = 0.0). 2. The cat moves forward the distance to the dog. 3. The dogs wag their tails and hop. Copyright © 2012, Oracle. All rights reserved. 163
164. 164. Using the IF and WHILE Control Statements Creating an IF Statement (cont.) Steps to program IF statement (cont.): 2. Drag and drop the IF statement tile into code editor. Notice the format of the control statement. 3. Select True condition. Copyright © 2012, Oracle. All rights reserved. 164
165. 165. Using the IF and WHILE Control Statements Creating an IF Statement (cont.) Steps to program IF statement (cont.): 4. Select the object to collide (cheshire cat) from Instance menu. 5. In the Functions tab, drag the isCollidingWith function onto the True condition. 6. Select the target object to collide with (dog). Copyright © 2012, Oracle. All rights reserved. 165
166. 166. Using the IF and WHILE Control Statements Creating an IF Statement (cont.) Steps to program IF statement (cont.): 7. Insert the procedures that will be executed if the condition is true (if) and if the condition is false (else). 8. Run the animation and debug as necessary. Copyright © 2012, Oracle. All rights reserved. 166
167. 167. Using the IF and WHILE Control Statements IF Statement Steps Summarized To summarize the IF control structure steps: • You select the control structure (IF) tile • You choose the True conditional option • You specify the True condition • You specify the actions to occur if the condition is true • You specify the actions to occur if the condition is false • You execute the program to observe the conditional behavior • You debug and test until the conditional actions execute as desired Copyright © 2012, Oracle. All rights reserved. 167
168. 168. Using the IF and WHILE Control Statements WHILE Statement Loops are used when a program requires one or more procedures to execute repeatedly. A loop can be infinite (continue forever) or conditional (stops upon a condition). Examples Infinite loop: The hour and minute hands on a clock continue rolling (unless the batteries run out!). Conditional loop: The propeller of an airplane turns while the airplane is moving or flying. Once the airplane stops, the propeller stops turning. Copyright © 2012, Oracle. All rights reserved. 168
169. 169. Using the IF and WHILE Control Statements WHILE Statement Flowchart The While control statement performs conditional loops. The While control will perform instructions while a condition is true; otherwise it will stop the instructions. Example: The Queen continues to move forward, unless it collides with the Playing Card. If the Queen collides with the Playing Card, she stops and turns around to face the camera. While the Queen is False Queen stops and collision End turns around free True Queen moves forward continuously Copyright © 2012, Oracle. All rights reserved. 169
170. 170. Using the IF and WHILE Control Statements WHILE Statement Placeholder Consider the portion of the While statement that reflects the true condition – while the queen is collision free. To create the While loop construct using the While tile you must specify an initial true or false placeholder value that is then replaced with the actual condition. Copyright © 2012, Oracle. All rights reserved. 170
171. 171. Using the IF and WHILE Control Statements WHILE Statement Steps Steps to program the While control statement: • Select the moving object from the Instance menu. • Drag the While control statement tile into the code editor. Select the True condition. Copyright © 2012, Oracle. All rights reserved. 171
172. 172. Using the IF and WHILE Control Statements WHILE Statement Steps (cont.) Steps to use the While statement (cont.): 3. Position the moving object so it is facing the target object to collide with (this will help us test if the while statement works when we run the animation). 4. Drag the move procedure into the While statement. Select forward and 1.0 for the distance. Copyright © 2012, Oracle. All rights reserved. 172
173. 173. Using the IF and WHILE Control Statements WHILE Statement Steps (cont.) Steps to use the While statement (cont.): 5. Drag the IsCollidingWith function of the queen object onto the true argument and select the target object (playingCard in this example). Note that in this example we are specifying the While condition after specifying the action to occur. It is perfectly fine to program either part of the While loop first. Copyright © 2012, Oracle. All rights reserved. 173
174. 174. Using the IF and WHILE Control Statements WHILE Statement Steps (cont.) Steps to use the While statement (cont.): 6. From IsCollidingWith menu, select the NOT isCollidingWith argument to invoke the opposite action. Copyright © 2012, Oracle. All rights reserved. 174
175. 175. Using the IF and WHILE Control Statements WHILE Statement Steps (cont.) Steps to use the While statement (cont.): 7. Drag the turnToFace procedure below the While condition. Select this.Camera as the target. Copyright © 2012, Oracle. All rights reserved. 175
176. 176. Using the IF and WHILE Control Statements WHILE Statement Steps (cont.) Steps to use the While statement (cont.): 8. To test this program, move the Queen to different positions. Include a path that collides with the playing card, and one that does not. Run the animation and debug as necessary. Copyright © 2012, Oracle. All rights reserved. 176