Alice: A Visual Introduction to Programming Chapter 1 Part 2

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

The Alice System 1-3

Open SnowLove in Examples 1-4

Executing Alice Program 1-5 PLAY

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

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

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

Objects Anything that can be identified as unique from other things How is an object unique? o Has a name o Has properties  Color, opacity, etc. o Can perform actions (methods)  Associated actions (move, turn, think, etc.)  Tasks it can carry out 1-9

Object Properties 1-10 Object Selected Change Properties Object Selected

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 Have a ghostly appearance 1-11

Objects and Object Parts 1-12 Objects are made of other subparts Snowman made of: o head  topHat  leftEye  rightEye  carrotNose  mouth o leftArm o rightArm o Bottom Objects named in “camel Case” format o 1st letter is lower case o Upper case next word’s 1st letter

Methods o Set of instructions to perform task o Default method  world.my first method 1-13

Methods  Each object and its subparts can be manipulated with methods o Move o Turn o Roll o Say… 1-14

The World is an Object  Contains all other objects  Also has its own properties o Atmosphere color o Lighting o Fog 1-15

Checkpoint 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 move by itself? 1-16

Alice has Class(es)  Objects are created from classes  Blueprint that describes a particular “type” of object  Defines a particular kind of object 1-17 Animals Collection

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) 1-18

Class Instance in Alice  Class: Chicken  Instance: An object that is created from a class  Examples o Chicken o Chicken2 o Chicken3  Each instance has its own properties, methods, functions  Can manipulate each one individually 1-19

Creating a New World Create a new world o File  New o Choose template 1-20

Adding Objects Click on Add Object 1-21

Adding Objects: Scene Editor 1-22 Click on People collection thumbnail

Add Coach Place object in scene editor by o Clicking on it o Or drag it 1-23

Coach Object With Bounding Box 1-24

Saving Alice World Click on File then Save World Has.a2w extension 1-25

Demo: Saving a world Writing and testing an animation is an intense load on the computing system o Crashes can occur Best solution  Save your world every 15 minutes  Also save to a backup system Ex: USB flash drive 1-26

Checkpoint What is a class? Are classes or objects stored in Alice galleries? What are two ways to add an object to a scene? What appears around an object when selected? Where do you find an object’s properties? 1-27

3D Objects and the Camera  Alice world and objects are three- dimensional o Height o Width 1-28 –Depth – 3rd dimension } 2D objects

3D Movement 1-29 Motion is based on OBJECT’s perspective…our left is the Coach’s right Forward is perceived as the object getting larger as it gets closer to us. Backward is perceived as the object getting smaller as it gets farther away from us.

The Camera When you create an Alice world a camera is automatically placed in the world Displays image of world in Scene Editor window o Called camera viewpoint 1-30

Camera Controls Drive forward, backward, turn left and right Move camera up, Tilt camera up, down down, left, right You can make camera move faster by dragging mouse pointer away from center of camera control 1-31

Different World Perspectives Sometimes difficult to tell where object is in relation to other objects Fish looks like it should be in water Change world perspective o Look at fish from perspective of water instead of sky Also called Camera control or point of view 1-32

Homework Read chapter 1 Do tutorials o Tutorials 1-1, p 6 o Tutorials 1-2, p. 19 o Tutorials 1-3, p. 34 Due one week after assigned with 1 week grace 1-33