CRITTERS, BY JOE WALSH

The Critters program is my second
foray into the world of Artifical
Life (A-Life, or AL).  It is also
my first assembly language program
(other than the piddling programs
typed in from the book Atari Roots,
and the even more piddling programs
I made up to teach myself the
language).  Finally, Critters is a
work-in-progress.

Simply put, the program creates a
"world" on your screen, and borders
it with walls.  Then it randomly
places some Critters (some male,
some female (males are inverse video,
females are normal video)) and some
plants around the screen.

Subsequently, the Critters and
plants live by the rules I have
given for that world.  It's
pretty straight-forward.  Critters
can move, fight, reproduce, eat
plants, eat dead critters (yuck!),
or stay still.  Critters decide what
to do based on what they find
around them, and their "DNA".

Plants have a much simpler life.
They grow from seedlings to full
plants, then wilt and die.  When
they are at or near their full
growth, they can spore another
plant (if there is room for them to
do so, and if the wind is blowing
in that direction).

It's fun to sit and watch this stuff.
I am very interested in perpetually
changing display programs, so I
enjoy just sitting and watching
them go.  Others may want to dabble
in this little world, so I have
provided a couple of meager
controls:

OPTION - Press this key to cause
plants to sprout in empty spaces.
Since the program runs through the
screen so fast, you don't have to
hold it down for long.  But, since
plants die out so quickly (twice
as quickly as all but the weakest
and least fortunate critters),
you may have to do this frequently
(or keep pressing it continuously
for a while) in order to get the
level of plant life you desire.

SELECT - Press this key to cause
Critters to be instantly born in
empty spaces.  Since critters live
relatively long lives, just a tap
of this key is usually enough to
put plenty of Critters on the
screen.

Finally, you may press the START
button to end the program and return
to DOS.  A couple of caveats, though:
1)  It only checks this key just
before it starts checking each
square for life from the top of the
screen down.  In other words, it
checks this key only about once every
second.  So, you may have to hit it
twice or so before it realizes you
want to quit (or just hold it down
for a second).  2)  While Atari DOS
clears the screen before putting it's
menu up, SpartaDOS does not, so you
end up with a screen filled with
characters.  Just type SHIFT-CLEAR
to clear the screen.  I don't have
MYDOS, so I don't know what happens
in that system when you exit to
DOS.

I hope you enjoy the program!
Let me know what you think.  I can
be found on the comp.sys.atari.8bit
newsgroup, or you can email me at
ransom22@delphi.com.


CREDIT WHERE IT IS DUE DEPT.:

I couldn't have made this program
without the following:

Atari 8-bit computers - my first
computer, and still the best.

Atari Roots, by Mark Andrews -
I thought I'd never find a book on
Atari Assembler that explained things
beyond how to add and subtract.
This book is great, and highly
recommended if you want to learn
ASM.

The people at OSS for putting out
the MAC/65 cart.
This includes Mr. Dunion, for his
Dunion's Debugging Tool, which is
included in the Mac/65 cart.

Mike at Fine Tooned Engineering,
for making the Mac/65 cart available
again.

Carole Borowski, for everything.

David Tipton, for making me realize
that it was time to get back into
the Atari 8-bit world after a six-
year hiatus.

All the kind folks at comp.sys.atari.
8bit, Atari Classics (both old and
new), and Computer Currents for
providing support to our community.

And to you, the user, for sticking
with the best computer platform
around.

- Joe Walsh
09/23/95
