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

What We Will Do Today Finish the material in chapter 1 Continue working on the tutorials and appendix 1 material in Alice Visual Programming Alice Concepts

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

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 Visual Programming Alice Concepts

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? Visual Programming Alice Concepts

Objects What is an object? What makes an object unique? 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 Visual Programming Alice Concepts

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 Visual Programming Alice Concepts

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

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 Visual Programming Alice Concepts

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 Visual Programming Alice Concepts

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 on ground usually have center between feet things that are held have center at point object would be held Visual Programming Alice Concepts

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 Visual Programming Alice Concepts

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

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 Visual Programming Alice Concepts

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 Visual Programming Alice Concepts

Visual Programming Alice Concepts

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