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1992-11-21
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Sirds V1.1 - by Ross Fuller
What is it?
===========
I wrote this program to generate Sirds (Single Image Random Dot
Stereogram). Sirds are images which can be seen in 3D when viewed
properly (see How to View). The program was inspired by an article on
Sirds in the April, 1992 issue of 'Games' magazine. 'WOW!" was the
expression everybody uttered when they first saw a Sirds, so I was
determined to be able to generate my own. After a lot of examination
of the examples in the magazine, I developed a method to generate
them. I then wrote this program in AMOS over a weekend or two in
September 1992.
How to view a Sirds
===================
Firstly, print one out (you can view on screen but the effect is much
better on paper). An example is included in Shapes.Sirds.iff in the
Sirds-Example directory. Print this out using Sirds or any IFF
print/paint program (see Printing for important notes on printer
preferences).
Once you have a printed Sirds, pick a well lit area, and look at the
page. Notice the two focal dots at the top of the Sirds. Look at them
and let your eyes go blurred (unfocused). ie. Focus beyond the page.
When you see those dots as three dots, concentrate on the middle one
and hold that focus. Just stare at the rest of the image and a 3D view
will gradually form. It will become really sharp and not look blurry
at all. Say 'WOW!'.
Don't worry if you can't see them immediately. Most people can see
them eventually. I took quite a while to see the first one. It's worth
the wait. I've found those that see the three dots quickly usually see
them straight away. I have found a few people that can't see anything
at all, but they're rare.
Generating a Sirds
==================
First step is to paint a picture of the scene you wish to generate
into a Sirds. Use any Paint package to do this and save as an IFF
picture. Sirds supports 320/640 x 256/512 PAL resolutions (NOT HAM or
Overscan). NTSC equivalents should be OK but I haven't tested this.
When painting, use colour 0 and the middle colour in the palette (ie.
8 in 16 colour palette, n/2 in n colour palette) as GROUND level. That
is what you see as background. Use colours below the middle colour as
objects below the page (1..m-1), and those above as objects above the
page (m+1..n).
Next, run the Sirds program and load the IFF picture. Using the mouse
and Left Mouse Button, select a portion of the image to generate a
Sirds from. Leave a bit of border for best results (some background
helps the eyes focus properly). Note that the generation can't be as
wide or as high as the total screen.
Select 'Gen Sirds' from the Mode menu. The program will then generate
a Sirds. If no selection is made with the mouse, it will simply enter
Sirds mode without generating anything (you can then load a previously
saved Sirds).
Once generated, you can then Save as IFF or Print the image.
Menus/Commands
==============
Select Mode:
Sirds goes into this mode on startup. Drag with the left mouse button
to select an area of the screen to convert to a Sirds.
Project Menu:
Load IFF - Load IFF picture
Colour Chart - Display Colour levels: G -n..-1
G 1..n
G=Ground colours, -n..-1=below Ground,
1..n=above Ground.
Click to exit chart display.
Help - Help screen for Select mode
About - Some information about the program
Quit - Quit the program
Mode Menu:
Gen SIRDS - Enter Sirds mode (Generate one if an
area has been selected.
Gen Sirds Mode:
Once generated or loaded, view a Sirds on screen by pressing and
holding the left mouse button. Also, a Sirds generation can be aborted
by pressing the ESC key at any time during the process.
Project Menu:
Load Sirds - Load a generated Sirds
Save Sirds - Save a generated Sirds (IFF)
Print - Print a Sirds to File or Printer
Help - Help screen for Gen Sirds mode
About - Some information about the program
Quit - Quit the program
Mode Menu:
Select - Enter Select mode
DOS Requirements & Compatibility
================================
Sirds v1.1 was written and tested for AmigaDOS 2.04. It uses commands
not available with 1.3. However, this is only when printing. AmigaDOS
1.3 users can still generate a Sirds and Save it as IFF. Print it
using any IFF print/paint program.
Sirds v1.1 has the following DOS requirements:
RAM: - uses the ramdisk while printing
Sys:Tools/CMD - used to redirect print to a file
Sys:Utilities/Display - used to print an IFF picture
Sirds v1.1 should work fine on an NTSC machine, but I haven't tested
this.
Sirds Files
===========
Within this distribution package are the following files:
/Sirds/
Sirds - Sirds program
Sirds.info - Sirds program icon
Sc3.iff - Title screen
Sirds.doc - This documentation
Sirds.doc.info - Doc icon
/Sirds/Sirds-Example/
Shapes.iff - Source used to generate example
Shapes.Sirds.iff - Generated Sirds
The AMOS File Requester
=======================
Mostly, the file requester is obvious. However, a couple of points for
those not familiar with it: Right Mouse Button will give you a
selection list of Disks/Assigns. The small circular button near the
top left of the requester will go to the parent of the current
directory.
Printing a Sirds
================
A generated Sirds can be printed from any IFF print/paint package or
from within the Sirds program. Selecting Print from the Sirds Project
menu will output to a file or printer using the current printer
preferences.
Printer Preferences are extremely important when printing Sirds as the
number of dots used to print the image is crucial. Scaling can ruin
the whole picture. Therefore, make sure Scaling=Integer in the
PrinterGfx Preferences setting. Set Density to whatever produces good
output on your printer.
You should set your Printer & PrinterGfx preferences to appropriate
values before running the Sirds program. Or use Amiga-A to multi-task
out of Sirds while running, set up preferences, then use Amiga-A to
return.
Note. The Printer and PrinterGfx preferences programs allow you to
save preferences as Presets, enabling you to load them later. This
means you won't have to worry about remembering the settings you need
for Sirds printing. See your AmigaDOS manual for information on how to
use Presets.
Program History
===============
Sirds v1.0 - July/August 1992
This version simply experimented with various methods to generate
Sirds.
Sirds v1.1 - September 1992
Provides IFF input from paint packages and Sirds Generation, Saving
and Printing (to printer or file).
Future Versions
===============
- Fix any reported bugs of course.
- Selectable GROUND level (not always 1/2 number of colours).
- Maybe include a small paint program.
- Depends on what suggestions I receive.
Thanks
======
John Everett and Paul Farrington for various suggestions and
discussions about how to generate Sirds.
Rod Taylor for the suggestion to use a paint package to generate the
initial image (with colours representing LEVEL).
Robert Cheeseman for testing.
Misc. Information
=================
Sirds may be freely copied and circulated. The program may be used for
any non-commercial or non-profit-making purpose.
Mail suggestions, queries, bug reports, etc to:
Ross Fuller
4 Inwood Place
Gowrie, ACT, 2904
AUSTRALIA