Loadstar 128 21/q21.d81/t.stereo boot

Text File | 2022-08-28 | 6KB | 127 lines

                           S T E R E O G R A M S

                              by Ian Adam, PE


    Random-Dot Stereograms are a new way of creating 3-D images on your
computer.  At first glance they look like a graphics program run wild, just
random dots all over the screen.  However, if you look at them just right,
you'll see patterns that either pop up out of the screen, or drop into the
screen.  For most people it will take several minutes before they see it,
but some see it right away.  Some people may never be able to see it.  You
must have sight in both eyes to see them -- that's why they're called
stereograms.

    The way to view a stereogram is to have it on screen (or printed out)
directly in front of you.  Some people like it close; others prefer it to be
held away.  There are two blocks at the bottom of the image, called guide
squares.  Stare at these but don't focus directly on them.  Try to focus
your eyes farther away, like at the far wall of the room.  As you do this,
the squares become four, because of double vision.  When you can make your
eyes focus so that you see three squares, your eyes are properly re-
focussed.  Move your gaze up to the center of the image without re-focussing
and the image should appear.

FENDER'S NOTE: The instructions for stereograms always mention focussing
"far away".  They never mention crossing your eyes.  In my opinion, the
trick is to look cross-eyed at it so that the two squares become three.  Be
patient.  Nome wasn't built in a day.

    When the program runs, it shows a sample image called "rings" which
looks like the ripples of water caused by dropping a rock in a pond.  Press
any key to move to the Main Menu.  Here you can review the last image, print
it or draw another one.  You can save an image to disk or load one from
disk.  You can change the shape or color of the dots, change the color of
the Menu and other screens, and tweak several other aspects of the program.

    There are ten patterns built into the program.  Press N from the Main
Menu and a list will be displayed in menu format.  Enter the number of the
pattern you want to see.  It will take up to a minute for the program to do
the math.  Then you go back to the Main Menu.  If you choose "10" for Custom
Letters, you are asked to enter up to three letters.  You may also enter
numbers and some punctuation.  Pattern 11 is called "Your Own".  Until you
enter the math for a pattern, there's no pattern there.

    Now the pattern is in the computer, mathwise, but it's not drawn on the
BASIC 8 hi-res screen yet.  This is the slow part and can take up to 10
minutes, depending on the complexity.  To draw the pattern, you must press
RETURN at the Main Menu.

    Before you draw the pattern you may want to adjust some parameters.  If
you change these later, they won't take effect until you REDRAW the pattern
again, so it's best to set the parameters first.  Here are the parameters
and their effects:

 Image depth (Range from -10 to +10) - Negative numbers cause the image to
be inverted.  The higher the number, the deeper the image will seem to be
imbedded in the screen.

 Shape of Dots - There are five shapes: Full square, Part square, Dot,
Stripe and Cross-hatch.  The Stripe seems to take longer to draw than the
others.  I like the Dot and Part square best.

 Density of Dots (Range from 0 [blank screen] to 1 [full screen]) - The
default is .5 which means that the image is half covered with dots.
Experiment to see which is best for you.

 Guides in Center (On or Off) - You may find that it's easier to have the
guide dots in the center of the image so you don't have to move your view
after getting the focus right.  Then you can press a key to get the guides
to disappear.  The default is to have the guides off.

 Show Perspective (On or Off) - This draws a small perspective image in the
bottom right corner so you can see what the image should look like.  It will
also print on the printout if it's showing on the screen.

 Image Colors (Range 1 through 16) - This only affects the stereogram
screen.

 Text Colors (Range 1 through 16) - Here you can set the colors of menus and
prompts.  They're not saved.

 Access Disk - This displays a menu allowing you to load and save images,
look at the directory and change drives.  The program boots up in the last
drive used.

 Print Last Image - Here you can install a new printer driver (default is
Epson which should work for most printers), change image height and density,
and set the secondary address.  The height and density refer only to the
printout, not the screen.  You may have to experiment with different drivers
if the Epson mode doesn't work.  The complete set of drivers that BASIC 8
supports is on the issue.

FENDER'S NOTE: Your interface should probably be in the Epson or transparent
mode.  STAR NX-1000C users should flip DIP switches 1 and 5 inside the
printer ON. If you cannot find a driver that works, I'm afraid LOADSTAR has
no further advice.  We're as stumped by printer problems as you are.

    STEREOGRAMS, written in BASIC 8, can only be modified if you have the
BASIC 8 package and editor.  If you have it, boot the editor, then load
"b8.rds".  Then check out the routines at 20100, 20200, 20300, etc.  The
routines that do the custom letters are at 21000 to 22000.  If you want to
add a routine of your own, do it at 22000.  You must know some hefty algebra
and geometry to do it right, but of course there's always
experimentation...

    The trick is to define a function eq(x) that will return values between
-1 and 1.  Use all of this range to get more depth, but try to stay away
from too many negative values because they create blank strips.  Then you
have to GOTO 25000.  Finally, you have to insert a DATA statement with the
image name.  Pattern 11 is waiting for you to enter it.  The program will
read DATA statements until it reaches the word "end".

    I hope you enjoy STEREOGRAMS.  Feel free to write me at the address in
the program with suggestions and ideas for new scientific programs.

IA

FENDER'S POSTMUMBLE: Ian, congratulations on a magnificent program.  As far
as I know, this is the first stereogram program for the 8-bit arena.  I'm
proud that LOADSTAR 128 scooped all of Softdisk's other magazines, but then
that's nothing new.  We also scooped 99.9% of the IBM world and 100% of the
Apple and Macintosh world.

                   ***** R - Run    RETURN - Menu *****