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Ictari Issue 44
ICTARI USER GROUP ISSUE 44 March 1997
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* m a g a z i n e *
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I C T A R I U S E R G R O U P
G Greenway, 8 Denmark Road, Reading, Berks, RG1 5PA. 0118 756668
http://www.elis.demon.co.uk/ictari/ictari.htm
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INDEX FOR ISSUE 44
==================
ASSEMBLER: Doom clone source code.
C: Fractal snowflake program.
Non-modal dialogue box demo.
GFA: Shareware compiler.
GEM object functions.
Number string routine.
MISC: TT assign.sys file.
JPEG USENET article.
Current membership list.
STOS: (Belated !) Christmas proglettes.
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EDITORIAL
=========
For reasons that escape me I recieved a catalogue for a Sinclair QL
PD library last month. Do people still use those things ? Perhaps it's
not so suprising. It's a sobering thought, that even though the ST had
multi-tasking and long filenames before Windoze 95, the QL had them
before the ST ! There are still plenty of people using old machines,
because they refuse to shell out for that which they don't need. The old
Amstrad PCW machines gave many people the power to put their words into
print for the first time, and I think they're still supported by a
news-stand magazine. The lab where I work contains two 5000 differential
scanning calorimeters, (don't ask..) one of which is still controlled by
an old BBC Master that runs rings around the 386 attached to its
companion !
What about the ST ? When it was released it had to compete with 286s
with four colour CGA. Now the big application everyone is interested in
is the Internet. The same old 8Mhz machines access the 'Net effortlessly,
while Netscape is something of a non-starter on a 286 ! (It has to be
said that an enterprising russian programmer has written a DOS-based WEB
browser that runs on 8086s...) Good software is still being written for
the ST, and the standard continues to improve. Look at UDO, ST-Guide,
CAB, Apex Media, the list goes on. Much of this software is being
developed by private individuals, in an environment where official
documentation and updated languages are becoming harder to find. Because
of this, groups like ICTARI must still have a part to play. It's nice to
see some more correspondence in this issue, the last one was something of
a monologue, and for a while I thought it *would* be the last issue. More
contributions are still needed if the group is going to continue.
I've noticed that Peter Hibbs didn't include people who visited the
ICTARI WEB site in the member's list. Given the frequency with which they
contribute, he had a point. Mark Wherry's comments look a lot more
positive, so I've put his name on the list. Can anyone help him with his
Magic problem ? Without the questions, there can be no answers. Many
vistors to the site have sent positive comments, but they're not as much
use as contributions. A few negative comments might be usefull too. How
could ICTARI be improved ? The members of the group (I sent a few final
demands last month, I'm afraid) seem to want it to continue, so there's
no reason to throw in the towel just yet.
Enjoy Theeselves,
Giles
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CORRESPONDENCE
==============
To: Everyone
From: Giles Greenway
Re: KillThings
Jason Railton isn't the only one who's been playing around with
Doom-type programs ! Up until recently "DigiTalis", author of several
public-domain games for the ST had been developing "KillThings", a
texture-mapped 3D maze game that runs on standard STs. Unfortunately, he
has now stopped developing software for the ST, but the last thing he did
was to put the latest binaries and source code on the WEB. Meanwhile, on
the comp.sys.atari.st USENET newsgroup, Brian Innes (ceebti@cee.hw.ac.uk)
has had this to say:
Here is the URL of the KILLTHINGS source and executables !
http://www.geocities.com/SiliconValley/6273/killtngs.zip
Now, I am thinking of finishing the coding of KILLTHINGS when I am
off university on my hols. Are there any programmers out there (68000
assembly language please :) who would care to help. Please e-mail me if
you do, with the subject KillThings.
Bye
I've put the contents of the archive on this month's disk. If any
ICTARI readers not on the 'net feel like helping out then let me know and
I'll put you in touch. The game "Destruction Imminent" has just been
released by Goodman's, and "Bad Mood" is being developed for the Falcon.
It's getting so you can't move for Doom clones !
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To: Everyone
From: Dave Seaman
Re: Press release.
Calling all ST programmers/graphic artists/musicians:
In an effort to encourage more quality ST programs, Dave Seaman of
Digital Designs is now offering a service called CONXIONS, which is a
periodical disk-mag style contacts forum. If you wish to be a part of
this exciting new venture, please send your name, along with your ST
skills, specialities (if any), systems supported, and preferably a small
(40k or less) example of what you can do. This will then be put into the
zine, and you can get in touch with, or be contacted by, other talented
ST users for new releases. The CONXIONS address is as follows:
Dave Seaman, CONXIONS, 49 Saunton Avenue, Harlington,
Hayes, Middlesex, UB3 5HG.
CONXIONS is a non-profit-making venture. The disk-mag will be
released into the PD, but contributors wanting a copy direct can get one
by sending a stamped SAE along with their disk.
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To: ICTARI
From: Mark Wherry
I downloaded all the available issues of Ictari yesterday, and I think
they're great ! I've not heard of Ictari before, but I'm certainly
interested now ! This is what I've been looking for, for ages ! I'd be
willing to contribute too, if you're desperate, the CAB protocol,
MIDI....Give me a ring! If any member knows anything about programming
MagiC I'd be greatful, the only docs are in bl**dy German!!
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To: Giles Greenway
From: Jason J Railton
Re: ICTARI Contributions
I've sent in several sets of STOS code which hopefully will be
spread out over the next few issues of ICTARI. Can you put the XMASDECS
and the SNOWFALL folders on fairly soon please ? They're already a bit
out of date.
If contributions aren't forthcoming, I'm not sure what you can do.
There are only a few members who regularly contribute, and I get very
pressed for time sometimes, particularly when I'm working on a bit of
code. I'd be happy for the disk to come out every couple of months, or
for you to add anything you can gather from the WWW to supplement the
disk.
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To: Jason Railton
From: Giles Greenway
Re: ICTARI Contributions
I don't think ICTARI should go bi-monthly just yet. If the next
issue looks good then it could be sent to Atari Computing along with a
letter and the address of the WEB site. If this draws in any new blood
then it might be worth approaching the AUKAUG with a view to pushing the
club at its stand at the next Goodman's Atari shows. With luck, all this
could really turn the group around.
You have a point about the Internet. Few members have access to it,
and the material it contains is of a different flavour to that found in
PD libarys. I'd still like to restrict it to tutorials and programming
tools that encourage people to contribute more. I wouldn't worry about
being pressed for time, you seem to have done your bit for a good while
yet.
---------------------------------------------------------------------
To: Giles Greenway
From: Jason J Railton
Re: Sierpinski Triangle
I wasn't aware of the CELLULAR AUTOMATA method for drawing the
triangle. I've used the random method several times (TWINKLER, in the
XMASDECS folder I sent in) is my best example, as it's tied in to a
colour triangle and colour cycling). FORMERS (see FRACTALS folder of my
contribution) uses the random method on several different types of
fractal. It even lets you plot your own.
One thing I did realise after seeing your explanation of the
CELLULAR AUTOMATA method is that to work out odd and even numbers in
Pascal's triangle, you only need one bit in binary. Thus the technique
lends itself to performing operations graphically, using the XOR (EOR,
sorry. I forgot that the designers of the 68000 were big fans of
Winnie-the-Pooh) function on several bits at once.
Start with a point, then copy the whole screen line (in one
bit-plane) down and to the right a pixel. Then copy the first line down
again, this time EORing it to the bit you just did. Repeat this operation
with the second line (shift the initial copy alternately left and right
to make the triangle spread out equally) and so on down the screen. In
this way you can render a screenfull in about 3 frames
- just a bit quicker than your C demo.
Unfortunately, I went and saved over my demo source for this method.
I'll have another go at writing it.
Oh, and I also found out that if you insert an extra copy of the
screen line, produced using the OR function instead of the EOR, every
2^nth line (not counting the lines you do get by the OR in this 2^n) you
can scale up the triangle. The original triangle is 2,4,8,16... 128 or
256 pixels high. If you smudge every 2nd row, the 128 pixel triangle
expands to 192 pixels high, neatly (nearly) filling the screen. If you
don't use exactly 2^n lines between smudges, or miss one out, the
triangle goes funny though.
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To: Jason Railton
From: Giles Greenway
Re: Sierpinski Triangle
That Twinkler demo of yours looks very impressive, as does the Xmas
tree one. I've put my recursive Koch curve program on this month's disk.
None of my programs are all that fast ! I doubt if the other methods of
plotting the triangle you described could work for moduli other than two,
but then that's the only one that gives a true fractal. There is a really
fast method of getting the modulo 2 triangle, though. You don't need the
previous generations of the cellular automaton. You don't even need
arrays ! If X is the current column of the triangle and Y is the current
row then the point should be plotted if X AND Y is zero. That's it. The
bit about expanding the triangle is interesting, though. If it can be
done in three VBLs then with a bit of screen-swapping could you produce a
realtime zooming triangle demo ? Another thing to try is to assign
colours to several moduli, and plot the point for the highest modulus
that yields a zero.
I can't recommend the book by Peitgen, Juergens and Saupe highly
enough, it really does contain everthing. It's a shame that there's no
port of Fractint for the ST, given all the nice video modes you can get
on TTs and Falcons, after all, there's a port for the Amiga. A
half-finished version is stored on the Umich FTP site. Maybe XFractint
could be compiled for the X11 port for MiNT, but the DOS-based versions
of Fractint are always the best on the PC. Fractint for Windows just
doesn't compare. Another job for you when you've put the finishing
touches to KillThings ! ;> I have a couple of fractal programs in the
pipeline. I've written a program that can take arbitrary complex
expressions (eg z = z**2 + c for the Mandelbrot and Julia sets, z =
cosh(z) + c for something much worse !) and produce iteration maps. It
*does* work, but it exists as a nasty piece of alert-ware, even if it is
GEM-based. I've also yet to see a program which plots the basins of
attraction for the Newton-Raphson method on the ST, other than my rather
cryptic .TTP program. Since this is a smaller project I'll give it a GEM
interface first, before returning to the more complex program. Nobody
hold their breath...
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To: Everyone
From: Jason J Railton
Re: Christmas Stuff
I've sent in several seasonal routines, based on STOS. Compiled and
GenFixed versions of most of the programs are also supplied. These were
originally sent in before Christmas, but they got lost in the handover of
ICTARI. Although they're not particularly seasonal anymore, it would be a
shame to waste them. Save them for next year.
First, in the folder XMASDECS are TWINKLER.BAS, TWINKLER.PRG,
FRACTREE.BAS and FRACTREE.PRG. TWINKLER is a fractal triangle with colour
cycling in low-res, and FRACTREE is a randomly generated fractal
Christmas tree in med-res. BASIC listings are commented to help you
follow them.
In the sub-folder M_CODE is SNOWMOVE.S. This is assembly source code
for a .PRG, to be used as a program loaded into a STOS memory bank. The
code can NOT be run on its own, from the desktop. You may however want to
use it as a subroutine in your own code.
The STOS BASIC programs SNOWFALL.BAS and SNOWBALL.BAS demonstrate
different uses of the code. A flashing point in the centre of the screen
is your mouse cursor. Use the left and right mouse buttons to draw and
erase lines on the screen to block or redirect the falling snow, and
press the C key to clear the screen and re-start.
SNOWTREE.BAS is the fractal tree generator from XMASDECS, but
converted to run in low-res with added snow.
SNOWFALL.PRG is a compiled and GenFixed version of SNOWFALL.BAS, but
I haven't provided compiled versions of SNOWBALL.BAS and SNOWTREE.BAS.
In all these demos, press SPACE to quit.
--------------------------------------------------------------------
To: Giles Greenway
From: Raymond Reid
resr@dial.pipex.com
Although I have not been able to contribute for some time, I hope this
will improve in the very near future, other commitments allowing. As you
will see, I have an internet address, which at the moment I have on trial
and may become permanent. I use a Psion Dacom Surfer Voice 33.6 modem via
a Pentium 100, and if I can be of any help to you please do not hesitate
to contact me. Despite having a PC, I still prefer the Atari for various
functions - and it's less hassle if it crashes!!
Lastly, best wishes in your enterprise as editor for Ictari , and
long may it continue.
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To: L. Maule Cole
From: Raymond Reid
resr@dial.pipex.com
Although I have not had time to look at your Gardener's database
program, I would be willing to help beta test it for you as I am also a
keen gardener and have both an Atari STe(TOS 1.62) and an STfm(TOS 1.4).
In reply to your comments about Megamax C, I have played around with
program listings from Compute's Volumes 1,2 & 3 which were intended for
the Megamax compiler and
found that it was easier to adapt Prospero C libraries to get the code to
run effectively - Prospero is easier to use.
If you wish, you can contact me and I will give you a copy of my
'adjusted' files/code, which may be of some use to you.
