CS320n – Elements of Visual Programming

1. CS320n – Elements of Visual Programming Alice Concepts Mike Scott (Slides 1-2)

2. What We Will Do Today • Finish the material in chapter 1 • Continue working on the tutorials and appendix 1 material in Alice Alice Concepts

3. Types of Animation • Two kinds of Alice animations • Movie • User “watches” animation • “machine-centric” • Interactive • User participates – clicks mouse,controls actions with keys • “user centric” Alice Concepts

4. Events • Animations that are “interactive depend on the user’s actions • mouse click • key press • others (head mounted device, dance pad) • Actions are events • Interactive programs are event driven Event window portion of Alice Alice Concepts

5. Interactivity in Alice • Animation with no interaction • Movie • DEMO Octopus Ride • Animation with interaction • DEMO Ice Skater • What are the events? • What response does the skater make to each event? Alice Concepts

6. Objects • What is an object? • anything that can uniquely identified from other things • What makes an object unique? • has a name • has properties • width, height, color, location, age, id# • has a purpose • associated actions it can perform • tasks it can carry out – things it knows how to do Alice Concepts

7. Classes • Objects are categorized into classes • Each objects is an instance of the class • All objects in a class • have the same properties • generally can perform the same tasks Rico Skipper Penguins Private Snoopy Kowalski Dogs Odie Opus Ren Alice Concepts

8. Objects in a Virtual World • In Alice, each 3D model is a class of objects • class: penguin • objects: penguin, penguin1, penguin2 Alice Concepts

9. Changing Properties of Obejcts • Properties of Object can be changed • Location can be changed by clicking and moving object • Orientation can be changed in the “Add Objects” View • Other properties, such as color, can be changed in the properties window when the object is selected Alice Concepts

10. Object Parts • Objects may be composed of parts • which may in turn be composed of parts • the whole object may be told to do something or an individual part Alice Concepts

11. Center of an Object • each object has center point • usually near center of mass, but really set by graphic artist that created object • spin point for object • things that sit or stand onground usually havecenter between feet • things that are held havecenter at point object would be held Alice Concepts

12. Distance • object’s distance from each other are based on the distance between their center points • may look like objects are zero distance away, but actually centers still some positive distance away Alice Concepts

13. Position in the World • The world in an Alice program models a 3D space • every object in the world has a positionx, y, z, coordinate relative to the center of the world • ground starts at center of world • axes (green = up, red = right, blue = forward) Alice Concepts

14. Adding 3D Text • Under the “Add Objects” window • Creates a 3D Text Object that can be positioned in the scene • Like other objects it has a host of behaviors and properties Alice Concepts

15. Adding “Billboards” • Billboards are flat, 2D images in a scene • Almost any graphic type can be added. • GIF, JPG, TIF, PNG, BMP • Select file and image is added to scene • Images must be created is some other program Alice Concepts

16. Alice Concepts

17. Class Work • Continue work on tutorials • Appendix A, • Part 1 • Part 2: Using Pop up menus to create an initial scene. Alice Concepts