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How DART works in Director

DARTís Relation to Director Metaphors

DART uses the metaphor of "Actors" to represent interactive media content on the stage. The stage is the visual window where the end experience is viewed. In augmented reality, this is often the user's viewpoint, seen through a head-mounted display. Live video from head-mounted cameras becomes the background of the stage and media content augments each frame of the live video.

A designer creates an instant of a cast member or any type of media (3D Objects, audio, video-based content, etc) as a sprite on the score. A sprite is a copy of a media element, where properties can be specific to each instance (think Object Oriented). The score is Directorís timeline (blocked units of time). Sprites rest on a block of time and only come into scope when the play head moves above the particular block of time. In DART, we use the DART-Loop property to keep the play head static. The designer can build logic (interaction, content flow) into the Actors under a loop and then jump to other loops on the score when desired. Designers have control over the appearance and disappearance of media content and can script the interactor (the user) into the application based on the sensing devices available.

When an Actor is placed on the score, it becomes a sprite or an instance of media content. The designer can decide what the content will be, what it will look like (color, transparency), where it will appear (location in 3D physical space), and what it will be linked to (3D position trackers, visual markers). The designer can add Events to the Actor to design the application around user actions and internal events.

A 3D World sprite extends the length of the score and contains behaviors and conditions that are needed for the entire application. This includes behaviors to set up the camera and trackers, as well as global Events.

Director's programming model

The sprites or behaviors that are placed on the score are essentially little nuggets of code that get executed in a certain way. Director moves through each frame (each column in the score) hitting each sprite (each row). Within each sprite, Director executes the code from each attached behavior in the order they are listed. Then it moves to the frame and repeats.

We use loops to control the flow of Director. A DART-Loop keeps the play head in one column until it is manually moved (or told in code to move) to a different frame. There are "On BeginSprite", "On ExitFrame", etc functions within each behavior where certain lines of code should be placed. Look at the DART-Lingo code and documentation to learn more.

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