NAME
     intro26 - the demo

SYNOPSIS
     intro26 [run]
     intro26 stop
     intro26 status
     intro26 scene [index]

DESCRIPTION
     Intro26 is a demo in the demoscene sense: a sequence of sixteen scenes
     drawn straight to the panel, one after another, with no purpose beyond
     showing what the machine can do with a page of paper-white and a few
     hundred kilobytes.

     It is worth saying what it is not.  There is no video, no frame buffer
     full of decoded pixels, no assets.  Every scene is generated as it plays:
     curves computed, cells stepped, a wireframe rotated, a halftone laid down
     line by line.  The panel refreshes about ten times a second at best and
     takes a visible moment to settle, so the scenes are built around that
     rather than against it -- plotted lines, accumulating patterns, a
     deliberate black flash used as a beat.  Several of them are after people
     who were making pictures with computers before the hardware was any
     faster than this one: Molnr, Truchet, Whitney, Muybridge.

     With no argument, or with run, the whole sequence plays from the
     beginning.  The command returns straight away -- the demo runs in the
     background and paints over whatever was on the screen -- so the shell is
     still there underneath and still listening even though you cannot see it.
     Type intro26 stop to end it and get the terminal back.  If left alone it
     stops itself after the last scene and restores the terminal the same way.

     Keystrokes do not interrupt it.

OPTIONS
     run  Play the sequence from scene 0.  The default.

     stop End the demo now and give the panel back to the terminal.

     status
          Print the current scene, its index and name, and how long it has
          been running.  Prints idle if the demo is not up.

     scene index
          Jump to one scene and play from there.  With no index it lists the
          scenes instead.

SCENES
     In order.

     0 teletype
          A cold-open boot log.

     1 lissajous
          Curves.

     2 plotter
          Squares, after Vera Molnr.

     3 truchet
          Tiles, after Sbastien Truchet.

     4 whitney
          A family of curves, after John Whitney.

     5 rule30
          A cellular automaton.

     6 mandel
          The Mandelbrot set, revealed as if by fax.

     7 fax
          A photograph, halftoned line by line.

     8 wireframe
          A Model 4 turning, in stop motion.

     9 tunnel
          Rings rushing forward.

     10 muybridge
          A gallop, generated rather than filmed.

     11 deghost
          The white-black-white flash, used as rhythm.

     12 inverted
          Text carved out of black.

     13 palimpsest
          Layers of computing history, ghosted over each other.

     14 carving
          An enso -- a single line, walked once.

     15 outro
          Credits.

     The listing prints a duration against each scene.  Those are upper
     bounds, not lengths: most scenes decide for themselves when they are
     finished and end well before the number shown.

EXAMPLES
     Play it:

          intro26

     Stop it, typing blind over whatever is on the panel:

          intro26 stop

     Look at one scene:

          intro26 scene
          intro26 scene 8

SEE ALSO
     slides(1), img(1), fractal(6)

NOTES
     The demo draws on the system workqueue at ten ticks a second, and each
     scene asks for the refresh it needs: none at all if nothing moved, a
     partial refresh for small changes, a full one when the whole page turns
     over.  Between scenes the panel is cleared with a full blanking cycle,
     which is the e-paper's own deghosting pass; without it the ink left by
     one scene's partial refreshes shows faintly under the next.

     Starting the demo cancels any refresh the terminal had pending, and
     stopping it hands the panel back.  Starting a scene while the demo is
     already running stops the old one first.

FRST Computer                                                       INTRO26(6)
