No Fragments Archive 8: Compilations 2/nf_archive_eight_v1.0.iso/MSA/EI/SPX/EI_SPX02.MSA/SPX_SHOW.DOC

Text File | 1985-11-19 | 10KB | 218 lines

A new era in ST graphics is born, the new era is

                       SPECTRUM 512 EXTENDED FORMAT

Concept by Gizmo of Electronic Images.
Programming by The Phantom of Electronic Images.

Check the 'CONTRIBUTORS' section to check on further contributions.

Thanks to Russ Payne for testing and fixing an STE problem (this was with the
original (Gizmo's) SPX show).

Also, thanks to Bertrand Petit for suggestions (see bottom).


Electronic Images is a part of The Inner Circle.

This program is public domain and can be freely distributed; as long as this
documentation and the program are suplied together in an unmodified form.

Ice packer is public domain and is a very nice packer indeed - ice packer is
programmed by Axe of Delight.
Spectrum 512 (C) Antic Publishing.


YOU SHOULD HAVE:
SPX_SHOW.PRG - The actual display program.
SPX_SHOW.DOC - This document.
UPDATE  .DOC - The update news.
SYNCTEST.PRG - The program which tells you if you're in sync or not.


SECTION 1 - History.

  Here's how the Spectrum 512 extended format was born: some time ago Gizmo
made a naughty picture that was over 3 screens high (it was called
STACEY.PRG) and it featured a new concept in screen pictures; you scrolled up
and down the picture to see the rest.  A while after that The Phantom did
some Spectrum 512 display routines, which gizmo used in his GFA Basic V3
programs to display pictures and do some incredible effects playing about
with the palette.  Then he had an idea: "What about the same kind of picture
format as STACEY, but in 512 colours?".  And thus was born BABY.PRG, a 3
screen high Spectrum 512 picture!  He then went on with this fab idea to do a
conversion program that allows you to display Spectrum 512 pictures at any
size (I.e. these could be from 1 to an infinite amount high, depending on
memory available).  The Phantom saw this program working (the first version
of SPX shower) and said "Hmm...  How about if I remove the top and bottom
borders?  It'll make it look much nicer!"  And thus, what even The Phantom
thought was impossible, was achieved.  After long hours in his trusty Devpac
2 assembler, the Phantom achieved it: Spectrum 512 pictures at an amazing
resolution of 320x276!!  And thus, the EXTENDED SPX SHOWER was born.  Gizmo's
file format allows you to have full 512 colour pictures, any size, scrolling
at 50 frames per second (real smooth) and at a resolution of 320x276.


SECTION 2 - Limitations.

SPX SHOW will *NOT* work on a mono monitor!

  The Phantom here, giving some of you programmers some specs.  Because of
the high amount of processing involved in displaying the picture (even more
than normal to keep the 320x276 resolution), you don't have much CPU time
left. You have about 7% left of the total processor time, which is enough for
a soundchip music driver (a decent one!) and some other stuff going on, but
sice the entire screen is taken up with a picture, there's not much you can
do except scroll it!  Also, with some modification, I realised that you can
free 60 or so cycles per scanline.  I thought that you can play a decent 4
channel digital soundrack at that point at 16Khz, but the amount of registers
you have free is extremely limited, and looking at that, the only one which I
see fast enough to do that anyway is Mr Music (our own 4 channel player).
Also, I could have put in pixel-by-pixel scrolling, but that would have
knocked out 7 pixels off the vertical resolution, and for the picture's sake
I left that idea in the waste bin.


SECTION 3 - Using the shower program.

For best results, it is best to switch your ST off for about ten seconds.
This procedure will sync the shifter chip properly - I.e. there will be no
funny dots in the picture (this is no big deal but it happens when the
shifter chip on your ST is not syncronised properly).  So, for best results,
do the above procedure.
I have now included a sync program that I found in one of my PD compilation
disks.  This program does NOT syncronise the chip, just tells you if it is
syncronised properly:  If you see white bands going down the screen, then it
is.  If not, switch off the ST again and do the above procedure.  It is best
to put the program in the AUTO folder.  Please note that the ST remains
sycronised even after reset, but NOT if you switch your machine off.  If it
is switched off, then it might or might not de-sync - do the above to re-sync
it!
Acknowledgements go to the unknown programmer of the sync program.

  Since this shower program is done in 100% machine code and uses no GEM
functions, you can install it in the AUTO folder to give you about 80K extra
of memory (that's about 2 extra screens).  Also, you can remove TURBO ST
since it uses its own screen driver, and TURBO ST isn't as fast as the one
used in the program (and you get more memory too!).
  This SPX shower will NOT corrupt any accessories or resident programs - it
even has a little leeway for naughty ones too!
  When the program has loaded, you are presented with a medium-rez screen
telling you how much memory you have free, how many screens you have for that
memory, and some other bits.

Using the file selector...

(The Phantom here)
  Since I kicked GEM in the teeth (to make the program work in an AUTO
folder) I trashed the normal file selector and put in one of mine.  When the
program boots up or comes back from displaying a picture, it reads the
current directory.  To choose a file you use the cursor keys to move the
highlighted box around, and pressing INSERT or RETURN to select the file.  If
you want to swap disks you can change the disk (not while it is reading the
directory!) and then press 'R' to reread the directory.  Folders are
denominated by a star before them, as in *FOLDER.FOL.  To go in the folder
just select it.  To go one folder out you select the *.. folder.  The *.
folder is the current directory folder - if you select this then the disk
will be re-read.  Thanks to Bertrand Petit for enlightening me on that!
  At any point in the file selector you can press 'Q' to quit the shower
program.

Near the top you will see the connected drives.  Pressing keys A to P will
select the drive.  So, for example, if you want to select drive E then just
press 'E'!

When the SPX picture has been loaded, you will get it displayed onscreen. Use
the up and down arrow keys (or the plus and minus keys on the keypad) to
scroll up and down the picture, so you can see the rest of it.  When you're
done ogling, press the spacebar to return to the file selector.

Pressing the HELP key at any time in the file selector will display a help
screen, with all the available keys.


Limitations.

(Phantom here)

The program will not work properly with MINT (the multitasking OS).  The main
loader part will, but due to technical reasons the display program will take
over the whole of the machine and chew up all the processing.  I have not
tested this, but I reckon that outside the display routine, it should work
reasonably under a multitasker.

To my knowledge, this program works on every make of ST.  It will NOT work on
a TT or an accelerated ST, since these knacker the display routine.  If you
have any ST in which the program doesn't work, contact me (The Phantom) at
the address below and I will try my best to solve the problem.

This is not a limitation, but I might as well mention it!  I have put in some
pretty extensive error handling in the program - perhaps too much actually.
It can recover if you take a disk out mid-load, put another in etc etc.  You
CAN crash it if you're real mean, but be assured that it won't crash at all
in normal operation, even if disk errors occur.


SECTION 4 - Contributors.
Since my plea of help in version 1.3 about logical drive swapping, I received
a letter from Bertrand Petit (A.K.A. Elrond the half-elf) of Imladris BBS in
France (Tel: [phone]) stating some facts about the way GEMDOS
treats logical drive swapping.  With this information, a few minutes later I
had logical drive swapping in the SPX shower!
Bertrand also stated that I was checking keyboard scancodes as his 'A' key
was being read as a 'Q' key - that would lead to some confusion for other
keyboard configurations.  He was right!  I have now changed the offensive
part and it should be hunky dory!
Also he suggested a help screen, so I put one in.  Thanks to Bertrand you now
have drive swapping and a help screen available too!  Thanks!


SECTION 5 - Bits 'n' bobs.

If anyone is interested in displaying their own SPX pictures, contact The
Phantom at the address below, and he will provide you with either an assembly
language driver or a GFA Basic V3 driver.  You do not need to mention us when
you use it in your work, since it's bloody obvious when you see a 320x276
spectrum picture!!!

Programs used in developing this:

(Gizmo) GFA BASIC V3 and GIFSPC.PRG converter by Steve Belczyk (THE best
converter around), and some assorted PC paint programs.
(The Phantom) GFA BASIC V3 (THE best basic!), Turbo Assembler and Devpac 2.

THe Phantom or Gizmo can be contacted either via Contact BBS
(London, England.  Tel: [phone]PM to 8AM UK time or (via mail)

The Phantom,
21 Bledlow House,
Capland Street,
LONDON NW8 8RU.


Have fun and enjoy this amazing picture format!


Other Electronic Images software tools:
SCREAM_3.PRG - A screen grabber with a search memory option.
DISK.PRG     - A disk archiver (a disk to file program).
MAPMAKE.PRG  - A 32x32 mapmaker as used in the Decade Demo.
FONTSAVE.PRG - A multi-bitplane image block saver (!).
MR_MUSIC.PRG - The fastest most versatile 4 channel digital sound driver.
               Currently in development is Version 2 (28% CPU at 16Khz).
               Contact The Phantom for the program/details.

Members of Electronic Images are:

Gizmo.
  The Phantom.
    Nightowl.
      Count Zero.
        Griff.
          Master.


This has been another Electronic Images software production!