The code (nucleus) and RAM space (envelope) of a biotelemorphic cell made with Macromedia's Director multimedia authoring package will consist of a Director movie projector (document player) and a single movie (document).
In Director, this is arranged simply by choosing an option from the "File" menu. This creates a projector and presents a dialog box to choose which movies (documents) the projector has to include. This is all it takes to create a basic biotelemorphic cell.
All Director projectors have to include at least one movie (document). For this initial example, a single mandatory document will be used ("pipe") consisting of nothing more than a single empty frame (screen) with one startMovie handler in the movie script:
on startMovie
go movie "the movie you want to open"
end
Opening the projector containing this "pipe" movie will then bring up a dialog box asking:
"Where is the movie you want to open ?"
The "pipe" movie, installed into the projector, is simply a programming trick to allow the user to select any starting document. In other words, when the projector is opened, it opens a completely empty cell and the user is allowed to choose the first document which is going to be used to determine the cell's activity.
Technical note:
Frames, in a Director document, are records which specify the appearance of the screen. The designer has the choice of using frames like the frames in a film clip, continuously cycling through different frames to provide screen activity. Alternatively, a single frame can be used and all the screen activity arranged through [Lingo] programming.
For the purposes of this book, we shall be working with single frames (screens) which are set to a "paused" state by putting a pause command in the exitFrame handler of any frame used:
on exitFrame
pause
end
This technique avoids the need for puppeting sprites - although all movements, sounds etc., have to be specifically activated by using the screen refresh command - updateStage.
In this way we can associate each frame with the layout and appearance of a particular computer screen which can be changed and manipulated using programmed instructions.
Fig 1.7
A player application which allows a choice of starter document
Opening up one of these empty multimedia players, which is set to ask which document it should read, can be looked upon as bringing life to the cell: causing the cell to wake up and ask the user to point to a document which will give it instructions (figure 1.7).
Although this sounds rather silly, remember, the document the user clicks upon can be a document which gets the cell to alter itself in some purposeful way.
It might, for instance, arrange for the cell to set itself up to accept instructions directly from the user rather than from a document. Amazingly, this will cause the cell to provide its own authoring environment - allowing itself to be authored without having to use the original authoring application package.
Fig 1.8
A player application configured to allow itself to be programmed through an editable text field
This is so remarkable that it bears repeating:
If the cell is provided with a suitable portal, the cell can be configured to provide its own authoring environment.
Note:
If you are not familiar with the Director authoring package, don't worry if this concept hasn't clicked yet.
You may have to read this several times before the pieces come together. In these first chapters we will be racing through a crude outline of constructing a basic biotelemorphic cell in order to get a grasp of the underlying concepts. In terms of the automobile metaphor we have an engine on a test bed.
Don't be disappointed or alarmed if at first the descriptions seem a little technical, too confusing, or even too simple - these will be explained in more detail later. The initial goal is to get some kind of conceptual picture so that we can rise above the level of technical detail to explore the practical applications.
We have seen how easy it is to create a basic biotelemorphic cell which comes with its own RAM envelope. Let us now proceed one step further, to give this cell a portal - a doorway through which we can send manipulative messages to the code in the cell engine.
copyright 1997 Peter Small - No part of this document can be used or reproduced in any form without express permission
Details of book, CD-ROM and online continuation - peter@genps.demon.co.uk