Coco Nutz! Vol 3 Issue 2, May 2007.pdf - TRS-80 Color Computer ...

CoCoNuts! May 2007 Volume 3 Issue 2
T H E L I F E A N D T I M E S O F T H E C O L O R C O M P U T E R
800 bytes (that's with comments,
spacing, and formatting), so it should
run on any CoCo, 4K and up, tape or
disk. I don't think I used any ECB
commands in there, so it should run
on a Color BASIC machines as well.
I tested it on Ramona (CoCo 3, DECB
2.1, 128K) and Ol' Betty (CoCo 1, F-
Board, DECB 1.1, 64K), as well as the
CoCo 2B and CoCo 3 (NTSC) emulation
in MESS.
Color Computer 3 users that have an
RGB or VGA monitor will want to type:
PALETTE RGB
prior to running the game. Might even
add a line there at the top:
1 WIDTH 32:PALETTE RGB
since the game will not run properly
out of 40 or 80 column mode.
I also recommend the high speed
POKE for those that prefer a little
more action. (I play it exclusively at
this speed. It's way more fun.)
CoCo 3: POKE 65497,0
CoCo 1/2: POKE 65495,0
Be sure to slow down before accessing
the disk or tape:
CoCo 3: POKE 65496,0
CoCo 1/2: POKE 65494,0
Some very old CoCo 1's may not be
able to use this POKE.
Game Play
Playing the game is pretty simple. You
find yourself on the VidGrid ensconced
in the ever popular and
overly cliché Lite Psycle. Your job is to
drive about and snag all the colored
squares you can before you bash into
your own light trail. But beware, the
evil video game controller gods have
set upon the field nasty green
squares that will smash you just as
easily as smacking into your trail.
Avoid them, drive like a maniac (using
the arrow keys) and rack up as many
points as you can!
I always liked weird scoring systems.
So here's one! Every space on
the screen your psycle moves you
get 10 points. Easy enough. When
you snag a colored square, though,
you get 10 points plus the ASCII
value of that square! Do you know
your CoCo colors? If so, hitting
those "higher" colors can net you
more points.
In the spirit of simplicity, there's no
exit. Hit BREAK when you're tired of it.
The Program
The program itself is dirt simple and
should be easily readable. This is
probably more explanation than
needed for this kind of program, but
for completeness:
Lines 10 - 50 just set up a few things,
like clearing the screen and setting X,
Y, and score variables.
Lines 70-100 are kind of neat because
they're "pushing" the CoCo's buttons,
as it were. POKE 135 it like mashing a
key. The values simulate pressing up,
down, left and right keys. In this case,
we're randomly setting the direction of
initial travel for the psycle. (By the
Page 18
way, to get a more "random" number
from the program, add the line 5
R=RND(-TIMER) to the listing. I didn't
notice much difference, so I left it out,
but for the purists, there ya go!).
Lines 110-140 just POKE in random
dots around the screen. I chose 25
after some experimentation, but you
can raise or lower this value according
to your tastes. Line 120 looks like a
mess, but it's pretty straight forward.
The value 1024 corresponds to the
first (upper left) location of the CoCo's
text (or low-res) screen. There are 32
times 16, or 512, locations (1024
through 1536) . So POKEing a value
into that location makes the CoCo
display the ASCII equivalent of the
value to the screen. We want a
random location somewhere within 32
columns (0-31) and 15 rows (0-14).
There are 16 rows on the CoCo's
screen, but we'll save the bottom bit
for score information. The second part
of the POKE selects what character is
to be placed at the screen location
selected previously. In this case we
want a solid color block. Value 128 is
a solid black block, to which we add