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Ictari Issue 13
ICTARI USER GROUP ISSUE 13 August 1994
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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
63 Woolsbridge Road, Ringwood, Hants, BH24 2LX Tel. 0425-474415
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INDEX FOR ISSUE 13
==================
ASSEMBLY Setting up system timers.
Vertical Blanking List (VBL) notes.
Colour cycling on raster lines.
Nick Bates. Sprite tutorial Part 2.
Keyboard equates file.
Compare routine.
Disk formatting code.
C C Graphics extensions.
Various C functions for use with GEM dialogs.
GEM Tutorial by J White. Part 3.
GFA Anagram generating code and recursion techniques.
Sound sample play routines.
STOS STOS extra extensions.
MISC Atari Questions and Answers file No 2.
Discussion on drawing tangents on curves.
Current membership list.
In next months issue of ICTARI (this may change) :-
ASSEMBLY STFM Overscan techniques.
Nick Bates, Sprite tutorial Part 3.
Code to calculate position of bouncing sprite.
Signed Integer fraction maths routines.
'Case' selection routine.
C 'Tiny' picture file reader.
Othello game code.
GFA GFA Manual Part 2.
Dialog box designer program.
STOS STOS accessory.
Rebound game.
Plazma display code.
MISC Atari Questions and Answers file No 3.
STE hardware information.
For future issues :-
Polyline drawing routines in machine code.
Bezier curve drawing routines.
Picture decompression routines for IMG, Degas, Tiny, PCX, PAC, etc.
Picture compression routine for IMG pictures.
HP DeskJet/LaserJet compression routines (Mode 2 TIFF).
Playing sound samples on non STE machines.
Picture switching techniques.
Printer driver code for printing mono/colour images.
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EDITORIAL
=========
MEMBERSHIP
ÿÿÿÿÿÿÿÿÿÿ
We have had a few more members join this month, welcome to them.
AUTO FOLDER
ÿÿÿÿÿÿÿÿÿÿÿ
Last month we included the DESKTOP.INF file in the root directory so
that members without hard disks can boot up in medium resolution.
Unfortunately this does not work for some STE owners because of a bug
in some versions of the TOS so the AUTO folder runs a 'fix' program to
overcome this problem.
GFA MANUAL
ÿÿÿÿÿÿÿÿÿÿ
Unfortunately, due to lack of room on the disk, we cannot include part
2 of the GFA manual or the index file but hopefully we can get these
on next months disk.
MICRO-MART ADVERTS
ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
A good number of members have joined the group as a result of our
adverts in the Computer Micro Mart magazine so we are continuing to
advertise in this magazine every few weeks. If any member buys this
magazine and does not need to advertise anything, perhaps they would
send the advertisment page into us so that we can use it for future
ICTARI adverts.
SAMPLED SOUNDS
ÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
In the October issue we would like to publish a number of articles and
source code on sampling sound and replaying sampled sounds. If any
members have information or source code for playing sampled sound on
STFM, STE or Falcons perhaps they could send it in. We particularly
need technical data on the various sound formats that are used on the
Atari machines, i.e. .AVR, .SPL, .SND, .SAM, STOS MAESTRO and any
others that may be used (note that we already have the PD file 'Audio
File Formats' by Guido van Rossum, V2.10 although a later version may
be of interest).
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CORRESPONDENCE
==============
To *.*
From J. Levon
When I set a dialogue to colour 8 in WERCS (the Falcon grey, as in
WinRec), in 2-colour mode it changes to black (as it should). This
makes the dial unreadable. In WinRec and similar Falcon programs, the
dial is white in 2-colour mode. How do I accomplish this ? Do I have
to dig into the resource file and change the colour to 0 (White) when
my program detects a 2-colour mode ?
Also, I can't get FLDLIB (from ICTARI 11) to work in an accessory.
Why not ?
Lastly, when using FLDLIB in conjunction with Let-Em-Fly (with Dials
to Mouse ON) the title bar of fld_do can corrupt the menu bar (when a
program is not using the menu bar). Is there any way to avoid this ?
----------------------------------------------------------------------
To Nick Bates
From Dick Teuber
I can sympathise with you about learning C on an inferior compiler
(although you don't say which one) but jumping up to Lattice C may not
be the best solution. Lattice C is very comprehensive but is also
quite hard to set up and use for any beginners to C programming.
I would suggest that you try and get hold of HiSofts C Interpreter
(for about 40) which is very easy to understand and use. It works
like a BASIC interpreter, you just write the code and then run it
without having to compile and link it first. This makes the program
writing time much shorter especially as the editor does a lot of
syntax checking before you even try and run it. Also any run time
errors are flagged up and therefore it is much less likely to crash
when the code is executed. It uses the standard UNIX and ANSI
libraries with over 460 library functions as well as good debugging
facilities, trace mode, variable dump, memory dump, pointer tests,
exception trapping and stack displays, etc which you do not get with
Lattice C. There are also a large number of built in window commands
which are much easier to use than the standard GEM window functions.
The manual is also very useful with a C language tutorial, function
reference and GEM toolbox. The main disadvantages are that the code
will run slower compared with a compiled version (although GEM calls
will not be noticeably slower), users will need the interpreter to run
the program and it only works in high and medium resolution. However,
the source code is compatible with Lattice C so that when you have
written and thoroughly tested a program it can be compiled using
Lattice C to generate a stand-alone .PRG program. As I have both
programs I would be happy to do the compiling for you (or anyone else)
when you are happy with your source code.
----------------------------------------------------------------------
To: Martin Cubitt & Paul Laddie Aka BYTEMAN
From: Martyn Armitage
Unfortunately it is not possible to format 11 sectors per track using
the XBIOS 10 system call. It's a problem that I encountered when
attempting to write a disk formatter some years ago. The routine will
attempt to do the format but fails miserably. The reason for the
failure is related to the amount of track data that has to be written
and the time available to do it in. A track, when formatted, consists
of not only the sectors, each consisting of 512 bytes, but also
address marks, track number, side number, sector number, sector size,
CRC checksums, filler bytes, synchronisation bytes, and data marks - I
don't think I've left anything out -, all of which take space and time
to write.
A disk that is formatted to 9 sectors per track will have 6969 bytes
of data written to each track. Of these, 4608 (9*512) are available
for the storage of user data. A disk formatted to 10 sectors will
consist of 7281 bytes, and a track formatted at 11 sectors/track will
result in 7893 bytes being written. It can be seen that each sector
consists of 612 bytes, of which 512 are user available.
The problem with formatting 11 sectors is that 7893 bytes have to be
written in the same time as would normally be used for a 9 sector
format, ie. one disk revolution. The XBIOS call writes the 11 sectors
but can't do it in one disk revolution and so the start of the track
gets overwritten by the end of the track.
The solution is to reduce, to the absolute minimum, the size of the
gaps between each sector, and the bytes that fill the end of the
track. This can't be done using the XBIOS routine and so one has to
resort to writing routines to create the formatted track data and to
control the WD1772 chip.
With the help of 'ST Disk Drives: Inside and Out', the 'BIOS' listing
in 'Atari St Internals' and disassembling the ROM routines myself, I
wrote an extended formatter. The program didn't get completely
finished. I think that the routines for busying the FAT entries of
damaged/unformatted sectors didn't get written, and maybe some small
inconsequential pieces. I do, however, personally use the program as
it is.
In order to save a lot of work on your part I've decided to release
the whole of the source code - written using DevPac2 - for the
program. This includes the GEM/VDI interface and routines as well as
the resource file, complete with headers, which was created using
'WERCS'.
There is a fair amount of source code that may be of use to others
reading this, particularly those interested in GEM/VDI programming.
The source includes routines for dealing with window re-drawing
(RDR_EVNT.S), obtaining the status, flags and string addresses of
objects within a resource tree (OBJCSTAT.S).
The code is old, not the most elegant, and could do with a bit of
sprucing up here and there. In fact, I no longer use most of the
routines supplied, having modified them beyond recognition, and
developed new ones over the years. For example the CLIP routine in
RDR_EVNT.S was my first attempt at the code, and it shows. The routine
I currently use is about a quarter of the size and much much faster.
*/ See ASSEMBLY\XFORMAT\ directory for code and program. ICTARI /*
To: *.*
From: Martyn Armitage
Can anybody help me with an algorithm? I'm wanting to write a program
to produce fixtures for a league. The problem: The number of teams is
variable between 4 and 24, but always an even number as one of the
teams can be 'No Game'. Each team has a fixture every week, even if
they are playing 'No game'. Each team plays every other team twice,
once at home and once away. There should be the maximum amount of time
between reverse fixtures (A vs B and B vs A); the second half of the
season can be a complete reverse of the first half ( 1st game of 1st
half = 1st game of 2nd half etc). No team plays more than two
consecutive games at home or away, and consideration needs to be given
to teams that share the same ground/pitch (they both can't play at
home at the same time). The number of divisions is variable between 1
and 4 but again consideration needs to be given to teams in different
divisions that share the same pitch/ground.
The teams are to be referenced by number rather than name in order
to comply with the League Update program that I have written.
I've spent many hours trying to come up with an answer but just can't
get my head around it. I'm sure there must be a formula somewhere that
describes the problem. Any help gratefully received. The algorithm
will be fine but if you just happen to have the source (I can cope
with Assembler, Basic -any variant-, and C).
----------------------------------------------------------------------
To ICTARI.
From Leslie W. Dewhurst.
Errata sheets for Atari Compendium: ICTARI 11.
I was interested to see that Mark Baker has obtained official
Errata for the first edition. How does one get this? I sent the
registration card from the back of the book off to America (not
very hopefully!) but have had no reply. I bought the book from
Hisoft at an exhibition.
Speedo GDOS function "vgt_get_table()".
The Atari Compendium says that the first of the seven tables to
which this function points, contains a "Master Mapping". Does
anyone know what this latter contains, what it means, and how it
is used?
Speedo GDOS function "v_ftext16()".
The Atari Compendium shows that there is a parameter "wstrlen",
whereas Hisoft's book "Modern Atari System Software" on page 144
omits it or anything like it from the binding for "v_wc_ftext"
(which is apparently another name for the same function).
Is this deliberate or is it a mistake? If deliberate, how does
one specify the length of the string? What is the form of a
"16-bit wide string" anyway? An array of word-length elements?
If so, the last element of the array must presumably contain two
null bytes, not one. But surely this could be taken to be the
Bitstream IDX value of a space character, and could not
therefore be used as a string delimiter? I am interested in all
the languages for which Hisoft give bindings.
----------------------------------------------------------------------
To STOS programmers
From George Hodgson
I'm trying to write a pools predicting program and need all the help I
can get with the design of a suitable database for recording the
matches played, goals for and against, etc, etc, these to be across
the page and not like the usual down the page type of address thing,
any help, suggestions, code, etc will be gratefully received.
----------------------------------------------------------------------
To *.*
From Diamond Software
Does anyone have the Protracker or Noisetracker replay routine ?
need urgently!
Cheers...
To Mic
From Diamond Software
We will send our 'new' sprite routines into Ictari soon. I'm not
sure what sprite routine Peter has of our ours, but I'm sure that it's
very old and slow. We'll also document the source and do some
explanations on how the routines work. We will also tell you other
methods.
To *.*
From Steven <Diamond Software>
Does anyone have any type of compression methods for picture or
PRGs? I coded one about two years ago, but it took too long (about
15 mins for a 50K file !!!!)
Also, anyone know how to load GIF, BMP and SPU/SPC ? Docs will do!
To EVERYONE!
From Diamond Software (again)
We hope you like the source codes that we have given away (see next
month). Later we'll give you a lot more source code and also some
documentation to go with them.
I have just been looking through old Ictari disks and I saw a notice
asking for some more STOS, C & GFA source code. Well, we have been
busy coding something in STOS for some time now and the project is
nearly ready for release, so we'll send that in as well some other
source code. We also have some full screen GFA overscan source that we
can't get to work 'coz we only have the GFA 2 compiler and it needs
compiling with GFA 3 Compiler. Does anyone want it though ????
As for C, well, we have only been coding in it for a few months and
our programs are pretty crap compared to others. Maybe in a few
months.
Quick hi to the Professor for his great GFA sources !! Love to see
some more...
*/ We second that last comment. ICTARI /*
----------------------------------------------------------------------
To ICTARI
From Geoff Smith
I am particularly interested in the forthcoming article about playing
sound samples on non STEs, I need to be able to do this from within C
and everything I have found about it so far is in assembler.
*/ We suspect that C would be too slow for the interrupt driven sample
playing code and that you will have to link in a machine code routine
to do this but if any C coders know different, please send us the
information. ICTARI /*
----------------------------------------------------------------------
To *.*
From John Hayward
I need some information on rare Atari computers/consoles. So far I
have got information and pictures on the following :-
8 bit machines.
400, 800, 600XL, 800XL, 1200XL, 65XE, 65XEM, 65XEGS, 130XE, 320XE and
Portfolio.
16 bit machines.
520ST, 520STM, 520STF, 520STFM, 520STE, 1040STF, 1040STFM, 1040STE,
4160STE, MEGA ST, MEGA STE, STACK, ST BOOK, STYLUS, ST PAD, OPTOFILE
CDAR 504 and 505.
32 bit machines.
Falcon 0303, TT030 and Medusa.
Consoles.
Pony, 2600VCS Mark 1, Mark 2, 7800VCS, Lynx 1, Lynx 2 and Jaguar.
The machines I still need information on are :-
1400XL, 1400XLD, 1450XL, 1450XLD, 1600XL, 130 & 260ST (128K & 256K
versions), 65XEP, Laptop XE, 5200VCS and entire PC range. These are
extremely rare or unreleased. The program I use is called Atari Museum
and covers the machines listed. It shows when the machines came out,
memory capacity, picture, etc. The program is only available on the ST
at the moment with the XE version in October. What I would also like
is someone with an 8 bit system and an ST who can exchange files
between machines as I have three 720Kb disks full of Neochome files I
want converted into GR7 or 8 pictures on the XE. My set up consists of
a 1040STFM, SC1224 monitor, SF354 drive, IBM printer, 65XE, 1050
drive, 1020 plotter and XC12 tape deck.
*/ Since this is a bit specialised for ICTARI, if anyone can help John
perhaps they would contact him direct at 42 Shelford Rd, Milton,
Portsmouth, Hants, PO4 8NT. ICTARI /*
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