Alice: A Visual Introduction to Programming. Chapter 1 Part 2

Transcription

1 Alice: A Visual Introduction to Programming Chapter 1 Part 2

2 Objects Alice uses objects o Tent o Soldier o Princess Objects perform actions Turn Move Fly Wave 1-2

3 The Alice System 1-3

4 Open SnowLove in Examples 1-4

5 Executing Alice Program PLAY 1-5

6 Controlling Runtime Speed Can increase speed of program Move slider of speed control Useful when troubleshooting to skip over parts of program that work Max of 10x normal 1-6

7 The Alice Environment Toolbar Scene Editor or World View Events Editor bject Tree Tile Tile Details Panel Method Editor 1-7

8 Review How do you control the speed of an Alice program that is being played? What part of the Alice environment displays a view of the world? What part of the Alice environment displays a list of objects in the world? What is a tile? 1-8

9 Objects Anything that can be identified as unique from other things How is an object unique? o Its name o Its properties o The custom methods or actions it can perform 1-9

10 Properties Values that specify an object s characteristics Can adjust them in the properties part of the details pane for an object Examples: Color, opacity, etc.

11 Object Properties Object Selected Object Selected Change Properties 1-11

12 Opacity How transparent an object is o Less opaque an object, more transparent Opacity of 100%, cannot see through the object Opacity of 0%, object is completely transparent Like clear glass An object with opacity of 0% is invisible A partially transparent object can be used to o Make something look far away in water o Give a ghostly appearance 1-12

13 Objects and Object Parts Objects are made of other subparts Snowman made of: o o o o head tophat lefteye righteye carrotnose mouth leftarm rightarm Bottom Objects named in camel Case format o o 1st letter is lower case Upper case next word s 1st letter 1-13

14 Methods Methods o Set of instructions to perform task o Can just be one o Default method world.my first method 1-14

15 Methods Each object and its subparts can be manipulated with methods o Move o Turn o Roll o Say 1-15

16 The World is an Object Contains all other objects Also has its own properties o Atmosphere color o Lighting o Fog 1-16

17 Review What are properties? What is the name of a property that o Determines an object s color? o Allows you to see through an object? What is a method? What do you call a part of an object that can moved independent of the main object? 1-17

18 Alice has Class(es) Objects are created from classes Blueprint that describes a particular type of object Defines a particular kind of object Animals Collection 1-18

19 Classes Gallery - collection of different object types (animals, beach, people, etc.). Class - each item found in the Gallery Two galleries are used o Local gallery (stored on computer) o Web gallery (maintained by creators of Alice) 1-19

20 Class Instance in Alice Class: Chicken Instance: An object that is created from a class Examples o o o Chicken Chicken2 Chicken3 Each instance has its own properties, methods, functions Can manipulate each one individually 1-20

21 Creating a New World Create a new world o o File New Choose template 1-21

22 Adding Objects Click on Add Object 1-22

23 Adding Objects: Scene Editor Click on People collection thumbnail 1-23

24 Add Coach Place object in scene editor by o Clicking on it Placed in default position o Or drag it You choose the place to position it

25 Coach Object With Bounding Box 1-25

26 Saving Alice World Click on File then Save World Has.a2w extension 1-26

27 Demo: Saving a world Writing and testing an animation is an intense load on the computing system o Crashes can occur Best solution Save your world every 15 minutes Also save to a backup system Ex: USB flash drive 1-27

28 Review What is a class? Are classes or objects stored in Alice galleries? What are two ways to add an object to a scene? What appears around an object when selected? Where do you find an object s properties? 1-28

29 3D Objects and the Camera Alice world and objects are threedimensional o Height} 2D o Width objects o Depth 3rd dimension 1-29

30 3D Movement Forward Motion is based perceived on OBJECT s as the object getting larger perspective our as it gets closer left is to the us. Coach s right Backward is perceived as the object getting smaller as it gets farther away from us. 1-30

31 The Camera When you create an Alice world a camera is automatically placed in the world Displays image of world in Scene Editor window o Called camera viewpoint 1-31

32 Camera Controls Drive forward, backward, turn left and right Move camera up, Tilt camera up, down down, left, right You can make camera move faster by dragging mouse pointer away from center of camera control 1-32

33 Different World Perspectives Sometimes it is difficult to tell where object is in relation to other objects Fish looks like it should be in water Change world perspective o Look at fish from perspective of water instead of sky Also called Camera control or point of view 1-33

34 Modifying Objects Use Mouse Mode Buttons 1-34

35 Modify Objects Move Up and Down Move Freely Turn Left and Right Tumble Copy When checked can modify subparts Resize Turn Forward and Backward 1-35

36 Center of an object Provides pivot or spin reference o Object spins around center At the center of mass Where it stands on the ground Where it is held

37 Orientation When you click on an object and rotate it you will notice arrows o Green points to up from the objects perspective o Red points to where object thinks its right is o Blue is forward to the object 1-37

38 Scene Editor Viewing Modes Single View o Viewing scene from World View angle Quad view o View scene from four views World View From top From right From front o Allows you to position one object in relation to another object Scroll Quad view Zoom 1-38

39 Relational Positioning in Quad View Notice how rabbit is positioned in relation to chicken World view From the top Zoom Scroll view From the right From the front 1-39

40 Using Coordinates Axes are measured in meters Point (0,0,0) is at center of the world Usually when an object is added to world by clicking on class then clicking on add instance the object is placed at (0,0,0) Can see position of an object in pointofview property X axis 1-40

41 Coordinate System 1-41

42 Homework Read chapter 1 Do tutorials o Tutorials 1-4, p. 40 o Tutorials 1-5, p. 43 Due one week after assigned 1-42

43 Homework Read chapter 1 Do tutorials o Tutorials 1-1, p 6 o Tutorials 1-2, p. 19 o Tutorials 1-3, p. 34 o Tutorials 1-4, p. 40 o Tutorials 1-5, p. 43 Do exercises in hand out Due one week after assigned 1-43