Autostereogram Generator
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by Jason J Railton in STOS Basic

for ICTARI User Group



  This program converts pictures prepared in Neochrome format into 3D
autostereogram images.  Run it and load one of the pictures provided
(BALL.NEO or SHIP.NEO) to see the effect.  Settings of 4 colours per line,
and a texture level of 1 give the best effect with these examples.

  Once finished, two crosses will appear in the middle of the screen.
Stare past them (bring your face close to the screen, if that helps) until
the images of the crosses overlap to form a third clear cross in the
centre.  You should now be able to see the 3D image amongst the patterns.

  Press SPACE to toggle the crosses on and off, and any other key to end.
You can save the result, or select QUIT on the 'Save' screen to start
again.  Select QUIT on the 'Load' screen to exit.



  To prepare your own screens, draw large, clear shapes in colours 0-15.
The colour represents the depth the shape will appear at - Colour 0 for
lowest, colour 15 for highest.  Make sure that you draw your 'higher'
coloured shapes over your 'lower' coloured shapes.

  Then redefine the palette.  Use a smooth sequence of colours from 0-15,
bearing in mind that the result fades down the screen from colour 0 to
colour 15.

  Now load the screen into STEREOGM.PRG.  Set the number of colours you
want to appear on each line.  For example, if you use 4 colours on each
line, the first line will be made up of a random pattern using colours 0, 
1, 2 and 3.  This will fade down the screen to the last line, which will
use colours 12, 13, 14 and 15.

  Then set the texture level.  This is the number of colours the random
pattern can jump from one pixel to the next, and so is limited by the
number of colours set per line.  A value of 1 moves smoothly up and down
the palette.  Higher numbers give more scattered patterns.



Jason J Railton
13th August 1997