





       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!!

     --------------------------------------------------------------------

   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.


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   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...


     --------------------------------------------------------------------

   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.


     --------------------------------------------------------------------

   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.














