Description
Issue 34
| Item | Author | Description |
|---|---|---|
| Menu | Andy Monk | |
| Magazine | Speccy Trade-Ins, Campion - The Spreadsheet Released | |
| Letters | More Of Speccy-Game Converting Debate | |
| Convertor | Stefan Drissen | Soundtracker To E-tracker Module Convertor |
| WW Demo 2 | Martin Bell | Brand New Level Of Waterworks |
| Suet | Robert Brady John Vincent | Two Shoot-'Em-Ups |
| Bunj Wobl 2 | Patrick Griffiths | Programs By Bunj Wobl |
| Mc Pt 23 | Steve Taylor | Multi-Tasking On Sam |
| E-Tunes | Music Done On E-tracker | |
| Sorcery Demo | Nigel Kettlewell | Demo/Advert For Days Of Sorcery |
| Invaders | Chris White | Diy Space Invaders |
| Zapp Demo | Paul Horridge | Mc Demo |
| Pacman | Leszek Chmielewski | Vector Animation |
| Squarius | Roy Gardner | Game |
| Gif Convertor | Dan Dooré | Don't Be So Sure... |
| App Launcher | Dan Dooré | Sort Through Files On Discs |
Magazine
BM Editorial
Hello again. This has been a very nostalgic month for me; first
of all I dug out all my Spectrum games and spent a pleasant
couple of days recapturing the joys of games like Room Ten,
Exolon, The Sentinel. Great fun. On a sadder note, I chucked out
all my old copies of CRASH, way back from issue 37 at the start
of 1987 (FRED editors need a lot of space, and 50-odd CRASHes
take up quite a lot of that commodity). It made me feel really
really old. Thank God I didn't keep them for another 5 years, or
I'd feel utterly decrepit by chucking-out time.
At Wm Low, where I work - not because I need to, of course; the
£13000 per month that Colin gives me's more than enough. I just
like erm, the atmosphere there. Yes. That's right - anyway,
they've just introduced barcode-readers at the checkouts, and
I've just come back from an "exhilerating" evening being taught
basically what flaming barcodes look like! The words "insult to
intelligence" spring to mind. Honestly. Makes your average ST
owner seem interesting.
BM News
Not much news this month, which really is quite surprising. I
may as well just repeat the contents of last issues newsletter
which accompanies subbers' FRED disks (see what you non-subbers
miss out on?).
The old SAMCo idea of giving people £50 off the price of their
SAMs when they trade-in a Spectrum is to be re-started, although
to be honest I can't remember the first time it was in
operation. Anyway, to get this £50 discount (a very hefty
discount, it must be said), send in any model of Speccy,
including manual and power supply, and claim your £50 off!
Simple eh? I can't for the life of me imagine what they'll do
with stacks of old Spectrums, but it's thankfully not my
problem. I suppose they could burn them on Nov 5th or something,
or maybe use them as frisbees. Incidentally, has anybody else
ever tried to force open an old rubber-keyed job? It's well near
impossible! I adopted the old "ram a chisel in the interface and
pound at it like mad" method and it took AGES! Don't try this at
home though kids - remember I'm a qualified weirdo...
BM News
You might be pleased to hear that now you can order certain
Revelation titles direct from FRED, which means:
1- You can buy Wop Gamma, Manic Miner, Batz 'n' Balls or The
Secretary with the same cheque as your FRED subscription
2- You get the usual FRED subber's discount (if you're a subber,
that is). Wop, Manic and Batz are all £8.99, and The Secretary
is a nice £12.99, so if you're a subber and buy all three that's
a saving of £5! Good eh?
If you want a title that isn't on the FRED price list, phone up
and we might be able to get it for you anyway, being the helpful
types that we are (easy for me to say - I don't have to answer
the phone all day!).
Remember: if (and only if) you're a FRED subscriber, you can
phone in an order and we'll trust you to send the cheque THE
SAME DAY (important), which allows us to give even faster
service than usual.
BM News
Days of Sorcery, the well 'ard adventure by Nigel Kettlewell is
also now available from FRED. See the demo on this very issue
and then decide you had too much money lying about anyway!
Did I mention last month that you can now get Outwrite from FRED
as well? I can't be bothered looking back at issue 33, so if I
did, you're getting told again: Outwrite is now available from
FRED.
We've had a number of demands for a list of what was on which
FRED, so once the summer holidays start (4 months! Bliss!) I'm
planning on beginning that not undaunting task.
Nothing to do with the SAM, but you may be interested to know
that Psygnosis has been taken over by Sony, that rather small
electronics firm.
BM News
Revelation have released a new spreadsheet package called
Campion. It's been in development for ages and ages, and I for
one had completely forgotten about it. I haven't seen the
package yet, but I believe Colin's got a copy lying about
somewhere, so I'll try to have a wee peek in time for FRED 35.
Hmm. What else has been happening recently? Well, Etracker and
Wop Gamma have been reviewed in YS, and although I haven't seen
the reviews yet, I'm sure they'll be pretty favourable.
Getting away from the Coupe again for a moment, you may not have
heard that there's a "Lemmings" single been released. I've not
heard it yet, and the fact that it's been out since May 5th
suggests it isn't likely to become one of the year's biggest
hits. Apparently there's a whole ALBUM of music/sounds from the
Amiga version of Mega-Lo-Mania; I'd hate to see the sad b*****d
that buys that album...
BM This Is A Colin Free Zone!
Yup, not a single word from Colin this month, due in part to the
fact that he told me he didn't have anything that needed
mentioning. Never fear though - I'm sure he'll find something
to waffle about in time for next month.
Some of you may have noticed that this (if all goes well) and
last month's issues have been slightly earlier than other recent
issues. We're happy to say that the duplicators, it seems, have
finally started getting their priorities right, and now a
production run of 200,000 for a glossy magazine's coverdisks
plays second fiddle to the 8 or 9 FREDs that need done. Well
done Mr Distributor! Having said all that, however, they'll
probably take 3 months to do this issue and you'll get it mid-
September or something.
Showing a complete lack of continuity, it's slightly ironic that
a News section begun with "Not much news this month..." managed
to last four whole pages...
BM On The Disk
Kicking things off this month is Mr Ubiquitous himself, Stefan
Drissen, with what could be an essential utility for musicians;
the Spectrum Soundtracker to SAM Etracker convertor! Hurrah!
Extensive-ish documentation is provided by the man himself,
which should tell you all you need to know.
Waterworks is a brand new level, just for FRED, of the hit game
Waterworks. Cynics will claim it's just another attempt to
publicise the game, but nay, 'tis not: this is simply a never-
seen-before level to give you all hours and hours of "fun".
Think about it; if we did just want to show off the graphics and
sound we'd have used the same demo as last month, but no no,
FRED likes to give you all little treats now and again, and this
will appeal to both those of you who bought the game and those
who haven't (yet!). Keys are QAOP & space, or joystick. Press
fire to start, and good luck! NOTE: it will seem at times that
the level is impossible, but it's not because I completed it!
(And it only took me about 2 hours to work it out). Thanks to
Martin Bell for providing this nice level.
BM On The Disk
SUET; a couple of games by Robert Brady and John Vincent, both
use the joystick keys, and that's all I'm saying. Find out for
yourselves what the cryptic title means...
Bunj Wobl 2 is the second set of programs by Bunj Wobl. Both are
pretty self explanatory.
Steve Taylor has returned! The man who knows more about machine
code than I know about Jamaican holiday resorts (!) brings you
the latest in what can only be described as "a very long series
of machine code lessons". Ah, I remember the days when we were
amazed he kept at it for the first five lessons!
E-Tunes features a new and improved player, plus a new and
(hopefully) improved screen just to prove I do put in the
occasional bit of creative effort. The E-player now gives the
title and author of the tune being played, so it's goodbye to
Johnny Anonymous for all you musicians out there.
BM On The Disk
Sorcery is a demo written by Nigel Kettlewell, and I've got a
sneaking suspicion that he's trying to sneak in an advert
somewhere in that demo; see if you can spot it...
Invaders; Chris White continues his guide to writing a Space
Invaders game, and if you were lost in the first couple of
lessons I'd advise you not to even think about trying to follow
this one.
Zap! demo by Paul Horridge is a debut demo, and while it may not
be the largest demo ever seen, it's undoubtedly an impressive
little thing.
Bits N Bobs - before I begin there have been queries about why
the new screen says "Bits and Bobs" as opposed to Bits N Bobs.
The reason for this is that the little "N" on its own looked
ever so slightly crap. Explanation finished.
BM On The Disk
The programs actually on Bits N/And Bobs are a GIF screen
convertor by Banzai, an application launcher, again by Banzai,
another vector animation (even better than last month's I
reckon) by LCD and Squarius, a game by Roy Gardener. All are
explained fully internally, so you don't need me to bore you
with extra info.
A Wee Preview
We don't normally let you know what's going to appear on future
FREDs (basically because we never really know ourselves until a
couple of days before the deadline), but in a fit of
organisation I can actually reveal some of the features we've
got lined up:
- another converted Speccy demo by Stefan Drissen which is bound
to contain an out-of-date scroller by then
- a great little game from Bunj Wobl, involving the bursting of
little bubbles (bet you can't wait now!)
BM A Wee Preview
- a couple of AXE's irreverant doings
- an article on the true speed of the SAM and ways to manipulate
it by Stefan Drissen
and all the regulars like screens, E-Tunes, adverts, Bits N
Bobs, etc. Could be good, could FRED 35...
BM A Bit On Piracy
Yeah, yeah, piracy. Everyone claims to know that "Piracy kills
the software", but very few people seem to care enough to stop
doing it; it's a fact that the Amiga is losing developers left
right and centre solely because of piracy, and there are well
over a million Amigas in the UK alone; SAM has a few thousand
users and piracy looks set to be as much of a problem as it is
in for the Amiga market.
Those brave enough to take the risks involved in producing and
publishing software (yes, RISKS - profits aren't guaranteed on
any computer never mind the Coupe), including FRED, are aware of
the fact that piracy is around on the SAM, and are even aware of
who is responsible in a significant number of cases thanks to a
few concerned readers who are not daft enough to fall for the
argument that you can't "grass up yer mates". Apart from
anything else, certain friends are undoubtedly helping to bring
about the end of the SAM. The object of this article is not
simply to try and threaten a few pirates with legal action,
however.
BM A Bit On Piracy
No, it would undoubtedly be possible to prosecute, that's not
going to do much to help get the Coupe on its feet.
What this article is intended to do is to get the pirates out
there to think about what they're doing. The old cliche about
every game copied being a direct loss to the company is
difficult to prove and easy to outmanoeuvre - "I wouldn't have
bought it anyway," is a common response. Looking at it like
this, it's easy to ease the old conscience about piracy; people
find it simple to accept that it's not doing any direct harm to
the software producers and so is not doing any harm.
Let me put the same argument a different way though: every
single game sold does benefit the software producers, and in the
SAM world each sale counts for much more than in areas where
sales count in the many thousands. A difference of only 10, even
5 units, can mean the difference between a success (costs
covered and profits starting to be made) and loss. EVERY game or
utility you buy increases the SAM's chance of a future.
BM A Bit On Piracy
So what does this mean? Well, for a start if everyone out there
with pirate versions of games buys the original that would help,
but it's not very likely, is it?
From now on then, buy software. Don't just wait for your contact
to send you the latest release. Buy it. It's not as if prices on
the SAM are unreasonable now is it? Most games are cheaper than
Spectrum ones!
And I'll say this again, in the hope that it maybe sinks in:
every item of software, be it utility, game, or even magazine,
which you buy makes a difference; a significant difference.
The Return of Sam Wheelbarrow!
The name's Wheelbarrow - Sam Wheelbarrow.
My kid sister Sarah's jailbreak was splashed all over the front
page. Obviously an accident at the printers, it made it
impossible to read. Chief Inspector Newton wanted me to track
her down, so I put an electronic tagging device on her duvet,
but I couldn't see how it was going to help. I'm not my sister's
keeper. In fact she wouldn't let me join her football team at
all.
I tried to tell him this over coffee and biscuits but he wasn't
having any of it, so I tried to tell him over tea and shorties.
He said I must have intimate knowledge of her. I said that must
be illegal. She'd been lifted by helicopter from the prison
roof. "If only we could find that helicopter," said Newton.
"Look, it says here she had musicsplosh consplatterdribbles,
does that mean anything to you?"
Sam Wheelbarrow
It did. Her last boyfriend had been heavy metal star Glossy
Pangbourne. We gave him a bell.
"It were just like a vasectomy - someone nicked me chopper while
I were asleep" he joked, amusingly. "And by the way thanks for
the bell." Glossy and his band Fraushagger claimed to be the
spokesmen for a generation. Obviously it was a generation with a
very small vocabulary. His helicopter had been stolen from his
Hounds Of Helipad, where he'd left it with the keys in the
ignition. Pangbourne had been the last to join the band,
replacing their original teenage vocalist Jimi Bon Moon (Jimi'd
died after developing a cocaine addiction while still at school
- a teacher had punished him by telling him to do 200 lines and
that was the end of him.)
Glossy had brought notoriety to the band. Every day he would eat
a live chicken for breakfast. Without milk. The high point of
the show was his ventriloquist act with a dead cat's head
reciting Satanic chants backwards while gargling goats blood.
Sam Wheelbarrow
They'd stolen a lot of the traditional Barry Manilow audience.
Pangbourne had nothing to gain by helping Sarah escape, his
Shagging Satan In The Sulphur Pit album was number one on both
sides of the Atlantic.
He showed us around his sprawling country estate, or Essex as it
used to be known. I didn't like it, it was too clean.
Rottweilers prowled the ground inside an electrified perimeter
fence, overlooking a shark infested moat and minefield. Either
he was very security conscious or liked a good laugh when anyone
tried to break in.
"You left the keys in the ignition of your helicopter" I said.
He told me this was for the benefit of the other band members.
"We operate a rotor - rotor, geddit?" he laughed. I didn't
believe him. He'd let his helicopter be used. Why?
His carpets were very clean, but in a few nooks and crannies
were traces of white powder. I knew he had an bad coke habit.
Sam Wheelbarrow
He always used to leave the last third of every can, and the
cost soon mounted up, but that wasn't enough to blackmail him.
I had Newton look into his police records. There, in the inner
sleeve of Outlandos D'Amour was what I'd been looking for. A
contract with Leagas McBeagas O'Toagle Boagle and Scrummerty-
Farquar Advertising Associates. Whoever had sprung Sarah had
used this to blackmail Glossy into letting them have his
'copter. "Hey man, give that back!" He made a lunge for me, and
a very tasty supper, but bribery was going to get him nowhere.
Pangbourne broke down. Newton and I jump-started him from a car
battery and he talked. "It was so long ago, I was young, I
needed the money, I signed a ten-year contract...oh God, if my
fans ever found out...!" I promised to keep his secret if he'd
tell us what we wanted to know. "So, he has a contract with an
advertising agency. What's the big deal?" asked Newton. "Have
you ever seen him in an ad?" I asked him. He hadn't. Glossy and
I knew why. I'd guessed it as soon as I soon those clean
carpets.
Sam Wheelbarrow
He was cleverly disguised, but someday someone else would
recognise it was Glossy Pangbourne in the Shake 'N' Vac ads and
then nothing would put the freshness back into his career...
BM 256K Owners Take Heed!
I'll be frank; FRED no longer guarantees that software will work
on 256k Coupes.
The reason for this is simply that the majority of readers, and
therefore contributors, have 512k SAMs and we cannot overlook
excellent material simply because a tiny percentage of readers
haven't got the necessary memory.
This may seem like the end of the civilised world to those of
you who don't have 512k, but it's not THAT bad; most of what
goes on the magazine will work. The occasional item will not,
however, and we wanted you all to be aware of the fact.
If you do find yourself stressed out at the prospect of missing
anything, feel free to phone Colin and ask if he has any memory
expansions going. They're not even all that expensive.
BM Credits
Editor: Brian McConnell
Generous Contributors:
Stefan Drissen (change!) AXE
Martin Bell Chris White
Bunj Wobl Banzai
Steve Taylor LCD
Andy Monk Roy Gardener
Nigel Kettlewell John Vincent
Robert Brady Paul Horridge
FRED Publishing, Phone [redacted]
[redacted] Cheques payable to:
FRED Publishing
===)>> Music (but no wrestling) ===)>>
BM The Music Section,
with FRED's Answer To Take That!
Yes, I'm back! After a whole month without my essential guide to
la musique, you can rest once more, safe in the knowledge that
at least the music side of your life is in safe hands (or not,
as the case may be).
Before I begin, I'm pleased to say that more of you are sending
in your own reviews; well done to those who have done so. This
month we'll have some from Andy Monk, even though they may not
be my style of music. It has been said that the true way to
judge the democracy of a country is its government's tolerance
of alternative ideologies, and I'm sure that that sentiment can
be manipulated somehow to make me look all magnanimous and kind.
As for me - I think I may as well do Suede's album. Right. Me
first then...
BM Suede
First things first; this band's very lucky indeed not to have
been drowned in the hype. The singles were good, but the hype
did get out of hand. The hype did two things: it got publicity
for the band, and it put a hell of a lot of pressure on them to
come up with a decent album.
As I said, the band are lucky in that the album's good enough to
allow them to retain some credibility. More than that, in fact.
It's a good album by any standards. One thing it's important to
point out about Suede is that there doesn't appear to be any
middle ground; people either love or loathe the music, and if
you thought that the singles were generally good, I'd advise you
to get this album. It's an average 45 minutes long, with 11
tracks, and only 3 of those could be described as "a bit crap".
The annoying thing is, when you're listening to the album over
and over it always seems that one of those 3 is playing. C'est
bizarre!
BM Suede
Another thing which I'd better point out is that the album is
definitely not an album to be played at a party or something.
The 4 singles are easily the most inspiring, as the rest of the
songs are much much slower, which is fine for a private
listening but would not go down to well when high tempo music's
the order of the day (or night).
Overall then? 7 out of 10.
And next, a couple of reviews by Andy Monk...
AM TANGERINE DREAM - ROCKOON
WHO?? Never 'eard of 'em? Well, twang me round till me flaky
socks cry out "Marmalade" if you haven't heard of this fantastic
band. I know they're, shall we say, getting on, but they really
are good.
Their music is, as Producer/Musician Edgar Froese puts it,
'Instrumental Rock Music'. I would describe it as Modern-Synth-
Instrumental-Rock-Orientated-Sounding-Music (MSIROSM). I'm not
that good at writing reviews actually, so I'll just briefly
describe general things like the colour of the inlay... No,
actually, I think I'll just go along and try writing a review!
Right, the instruments used are mostly KORG instruments (mainly
the T1 Workstation & 01W/FD - Excellent synths if you can afford
'em). There is also the much welcomed addition of an Alto-Sax
being played on 3 of the tracks (there's 11 in all - totalling
57 minutes of music).
Another welcome addition to this synth-esque music is the guitar
(12-string, Lead & Rhythm - mostly played by Edgar & his
brother, Jerome Froese), but above all, the keyboards are the
main attraction (I'm convinced it's all a big musical-advert for
KORG instruments!!).
The music itself is pleasant to listen to if you aren't too much
of an 'ead-banger...
Before I decided to shovel out 13 quid for the CD, I decided to
buy a cheap tape of older Tangerine Dream music to see what
their earlier stuff was like. The tape was a compilation of very
early stuff and ranged from late 60's to early 80's. I thought
'Mmm. This is a bit sad!' and I subsequently forgot I owned the
tape. I then found the CD again and, me being me, decided that
it had to be better than the tape. I then bought it. That was
one of my better purchases...
(That was a big paragraph!) - Anyway, if you like weird, old
electromagnet noises, then buy the older TD stuff. If, however,
you like New-Age-Instrumental-Rock-Music, then buy ROCKOON!
AM JAN HAMMER - BEYOND THE MINDS EYE
You must've heard of Jan Hammer, for it was he who composed ALL
the incidental and themed music in EVERY episode of Miami Vice.
Yep, he certainly was a busy bloke. He still is, in fact, a busy
bloke, 'cos he's just released his 3rd (or is it 4th) Album,
magestically called 'BEYOND THE MINDS EYE'. The music is
supposedly based on a Video of the same name (probably called
'BEYOND THE MINDS EYE - The Video') and is not, amazing as it
may seem, a concert of Jan playing this music. It is in fact,
and I quote the inlay 'A computer animation odyssey'.
The music was written for a series of spectacular computer
animations (which I haven't seen!) - Anyway this is a review of
music, not of Videos (although that's not a bad idea!).
There are 15 tracks in total (total time-49 minutes) although
the last track is the same as the first except with Vocalist
'Chris Thompson', erm, singing.
What is the music actually like? Good, atmospheric, absorbing,
clever, brain-numbingly weird is yer answer...
Unlike Jan's other albums (two that I know of and own), the
music was recorded using all KORG equipment (like Tangerine
Dream). There is no guitar, no sax etc... just Keyboards (and I
know from a reliable source that the keyboard being exclusively
demo-ed is one in the 01W range).
Again, it looks like everyone is out to demonstrate this
mysterious 01W range of keyboards for KORG.
Anyway, back to the review... This is more of the New-Age kind
of rock-ish music that I talked about with Tangerine Dreams
Album. The one track I really liked was called 'Nothing But
Love' because it reminded me of a certain female called Cl...
AHEM! Sorry, I was drifting away into nothingness land there.
Where was I? Oh, my fave track is probably 'Afternoon Adventure'
'cos it kind of breaks out into a frenzy of sharp chords and
thumping bass lines...
I suppose the most atmospheric track I can think of is called
'Midnight' (which is, I think the music for a film called
'Midnight Heat', I'm not sure).
If you liked Jan Hammer's previous Albums, then you'll love
this, it's really unlike his usual work, but in the same style
if you see what I mean...
Well, that's the end of this review. It seemed like a big advert
for KORG keyboards really...
Letters & Reviews
BM CONTENTS
01 - Contents
02 - Letter from Paul Horridge
04 - Letter from Stefan Drissen
10 - Letter from Dave Marriott
12 - Letter from Douglas Murdoch
16 - Letter from Ton Voon
17 - Letter from Toby Cooley
Letter from Paul Horridge
Dear Brian/Colin,
I enclose a demo which I have written, which I hope you'll
consider using in a future issue of FRED.
Some of the programs on FRED, such as the MC menu on issue 31
and the Flip 'N Hell game on FRED 32, refuse to work on my
machine. Is this because I only have 256K of RAM? Apart from
this, I think that FRED is an excellent magazine. I particularly
enjoy the demos, MC tutorials, and games. The BOFH was brilliant
- is it possible to bribe/threaten the author into writing some
more? If so, do it! Stefan Drissen's sprite article in FRED 29
was also very helpful.
Has Steve Taylor covered interrupts and/or vectors in his MC
Tutorial series? If so, which FRED issues are they in?
BM Reply to Paul Horridge
First of all, I say that it's pretty likely we'll be using your
demo, yes...
Secondly, you're right about the 256K RAM thing. And this month
sees a little announcement covering such "underpowered
machines"; we now assume that all readers have 512K machines,
and as such no longer make any guarantees that programs'll work
on lesser Coupes. The reason for this is not simply to get you
all to buy upgrades, but because the vast majority of FRED
readers do have 512K and it would be unfair to discard such high
quality programs as Flip 'N Hell simply to appease 1 or 2% (yes,
that's how small a minority you're in Paul!) of the readers.
512K expansions aren't really THAT expensive anyway, are they?
Steve Taylor HAS covered interrupts (inturpts, eh Chris?) and
vectors, and if my memory serves me correctly they were in, ooh,
issues 11a, 13 and 15 (and I can tell that you all believe me
when I say I haven't spent the past half hour looking for the
damn things).
Letter from Stefan Drissen
Stefan Drissen
[redacted]
Hi Colin and Brian,
Thanks for defending this sadly misguided soul. At least now I
can tell all my friends that I am a sadly misguided soul, and a
clever one at that. Boy am I glad I read FRED! Now do you see
why I want to take over? Just kidding, before I get into what's
on the disc I will write a bit of a reply to Andrew Penny's
letter.
Firstly, I do not WASTE my time converting Speccy demo's, it is
all involved in the learning proces of getting to know your
computer (my SAM) in and out. I also enjoy doing this because it
gives quite a bit of satisfaction for quite a little bit of
effort. For your information, converting Shock took say half a
day.
Letter from Stefan Drissen
Secondly, converting speccy games to SAM conversions is nowhere
near as easy as you imply; a few patches definitely won't do the
trick. I have given rewriting a Speccy game some thought, and it
shouldn't be too hard IF I were given the Speccy source code
with documentation. Even then there would be limits. If you look
at the ratio CPU speed against video memory, the Speccy wins
because it's got a quarter of the video memory at half the
speed.
Who wants Speccy conversions blown up to SAM format anyway, by
working in this way you will always be limiting the
possibilities. I'd rather see games from the PC on the SAM (for
example Dune, Dune II or the Sierra adventures).
I'd say that's enough on that subject and onto the disc
protector unit, it's pointless writing to me about it, write to
Edwin Blink because he is making and selling them (address in
scrolly).
Letter from Stefan Drissen
It is impossible that the SC_Autoboot ROM stops corruption of
discs, because it is a hardware problem, not a software problem.
What happens is that when you press the reset button the clock
signal for the floppy disc controller is disconnected. If the
FDC doesn't receive a clock signal its activity is undefined,
meaning it can be doing anything, including writing garbage to
the disc.
What I assume that the SC_Autoboot chip does is give an
interrupt to the disc controller before doing anything else,
this MAY stop the disc controller from doing any damage to your
disk. Why else would Steve Nutting order disc protectors from
Edwin? As far as I know, Steve is planning to sell them in Great
Britain, so you should be able to get them from him too.
I would also like to thank John Teare for mentioning he used my
colour BAR routine in Superleague. Here's a little tip for when
using lots of bars on screen (like in superleague). Instead of
calling the BAR procedure each time you could copy the line,
Letter from Stefan Drissen
interrupt colour table to a bit of memory after having set the
screen up right the first time. After that you only need to POKE
the line interrupt colour table with that bit of memory. This is
significantly faster. LET col$=MEM$(&5600 TO &5800) to store the
lines and POKE &5600,col$ to restore it.
Well, after that load of text here comes what's on the disc.
Firstly there is an article on the speed of the machine code
instructions on the SAM, something which I feel is rather
important to know if you are writing speed optimizing routines.
The theoretical speeds simply don't hold up.
Secondly there is another sadly misguided effort, a Speccy demo
consisting of 26 really good tunes and a scrolly. Originally
this demo had bars bouncing around the screen, but these were
too much of a hassle to get up and running (Speccy ROM routines
again). On the subject of speccy demos, since YS has stopped
sending me YS, I no longer have a supply of speccy demos to
convert.
Letter from Stefan Drissen
Either you say hurrah, no more Speccy demos, or you can send any
demos you want converted to me and I will see what I can do,
anybody who does send me a demo to convert will become famous
SAMworld wide. I am only interested in demos which work on a 48k
speccy and DO have music.
Last and of course least is an E-tune, it is a SAM remix of the
speccy tune AMIGA ONE, just to show what a soundtracker
convertor can be useful for.
A rather meager effort by me this month, but once again exams
are nigh. They should be history in three week's time so then I
can do some more coding.
Keep up the great work,
Stefan Drissen
BM Reply to Stefan Drissen
Well. There's not really an awful lot to reply to from that
little letter, is there?
Stefan's address is included for anyone who wishes to send
Stefan a Speccy demo to convert, and the demo he mentions will
be in FRED 35. Believe me, there are some excellent tunes, many
of which are cover versions of extremely famous compositions. No
doubt, however, he'll complain about the message in the scroller
being out of date by issue 35, heh heh heh.
As for the old "game-conversion" debate, I'm perfectly happy to
see quality original games released (and I don't want hundreds
of letters saying "there haven't been any truly original games
since The Sentinel on the Speccy" okay?). It's usually much
cheaper than aquiring licences which means cheaper games, and
more for the programmer. Having said that, however, I don't
suppose it'd do the SAM and harm publicity-wise if something
like Monkey Island was released on the Coupe...
- BRIAN
Letter from Dave Marriott
Dear FRED,
Yeah, book reviews might be a good idea (scroller on Etunes, ish
33 - BRIAN), either as a regular or an occasional item. ZAT used
to have a book review section, through which I got into CJ
Cherryh's excellent "Faded Sun" trilogy, which I'd never have
read otherwise. I'm assuming that the reviews will be of
tasteful stuff like sci-fi and Frederick Forsyth-type novels, of
course. I don't want to know about the latest Jackie Collins
sizzler; I'd sooner read wrestling reviews, or have my wisdom
teeth pulled out.
Secondly, is there any chance of putting a longer or indefinite
pause between screens in the Screen Display program, or
alternatively, having a keypress to "hold" a screen? You don't
really get enough time to take in some of the more intricate
ones.
Reply to Dave Marriott
It's always difficult discovering new authors isn't it? It's not
like you can listen to Radio 1 for wee tasters of authors' work.
Usually I just go by a particularly inspiring cover when I'm
totally at a loose end, which as the proverb states is not
wise.At the moment, I don't know if I will include book reviews.
Maybe I will sometime. You'll just have to wait and see, really.
The book reviews would be along the lines of sci-fi/horror, but
not Freddy F, because I think his books are a bit on the boring
side. Sorry, but they are. My Dad reads them; what more evidence
do you need?!
As for the Screens section, from now on there will be an
indefinite pause, so to continue you'll just need to press a
key. And they we don't listen to our readers' demands...
I take it you're not a great fan of wrestling? And I hope you're
not accusing Jackie Collins of being anything other than a
serious literary giant, up there with Dickens and Bronte? Dear
oh dear oh dear.
Letter from Douglas Murdoch
Dear Brian/Colin,
Just thought I'd drop you a line (gee, what an original opening
remark!) to commend FRED Publishing on its brilliant service to
the wide world of Coupe-dom. The last time I put pen to paper it
was to send off for Prince of Persia (my first game - I'm new to
the SAM scene) and within THREE days I received the game! Now
that's what I call excellent service - are us mere mortals
worthy of such dedication?
Anyway, down to business (sort of)(am I putting in too many
brackets (?)) (does it matter? (and is it grammatically
correct?)).
Where was I? Oh yes, business; I've managed to work my way
through to level 12 on POP but when I fight the evil mirror
image, I can kill him and he falls down - turning into Jaffa.
No tune plays (unless you put away your sword). I mucked about
for a bit, then, when I returned to the room that I killed old
Letter from Douglas Murdoch
Jaffy in, the mirror image appeared again. I hit him 4 times,
and then I died. Please tell me what you're supposed to do -
it's driving me mad. It takes ages to get there and then I get
killed. Is there a bug or is it just me?
Right, enough moaning, I'd better be off and let you read some
interesting letters. Before I go though, I must mention how
excellent the FRED disczine/magazine is; well worth the two
measly pounds per month - keep up the good work!
I was wondering if you couldd answer a couple of questions:
1 - Whatever happened to Enceladus/Graham Burtenshaw?
2 - Why are Faith No More so excellent?
3 - What's the meaning of life?
In case you end up printing this, I'd like to thank my
girlfriend, Gill, for lending me most of the money for POP and
putting up with me.
BM Reply to Douglas Murdoch
Well. POP does seem to be causing you problems, doesn't it? I
may as well put you out of your misery and tell you I've been
told needs to be done (I could never be bothered getting past
level 2, to be honest): when you confront your mirror image,
DON'T DO ANYTHING!! Walk right through the mirror image,
withough getting out your sword, and everything should turn out
fine.
Onto your other questions - Graham Burtenshaw gave up Enceladus
because of the fact that for some reason he thought getting good
A-Level results to be more important than diskmags (what an odd
notion). I believe the art package he was working on is still in
progress and will be released in a couple of months.
I put FNM's excellence down to Jim Martin's collection of
inspiring sunglasses, myself. Maybe that ain't all there is to
it, however. I'm glad you enjoy reading the music reviews. It's
always nice to find that somebody finds them even slightly
worthwhile.
BM Reply to Douglas Murdoch
I'll resist the temptation to say "42" to your 3rd question, and
give you my philosophy that it is in fact Roast Chicken from my
local Chinese take-away. Quite delightful it is, and although
not a great one for conversation it makes up for that with some
smashin' gravy. Hmmmmm.
If Gill's reading this - please give Douglas some cash to buy
Waterworks and/or Wop Gamma, 'cos they'll keep him occupied for
even longer than Prince of Persia did.
I have to say that your little Faith No More / Gateshead
proposition proved most interesting, and I'd be very grateful if
you could. You know where we are...
And what do you mean, putting your FRED order in the last line
of the page? That should be right up at the top, in huge big
letters: "YES! I WANT ANOTHER ISSUE! PLEASE, PLEASE, LET ME HAVE
ANOTHER ONE, OR LIFE WILL BE EMPTY!". A small tip now: get a
subscription to save loads on prices of games and stuff. - BRIAN
Letter from Ton Voon
Dear Brian,
I enclose a cheque for £20 to renew my subscription to FRED for
another 12 months. Keep up the good work!
{I interrupt this letter to point out that THAT is the way to
begin letters, Douglas Murdoch. Soory Ton. Continue... - BRIAN}
Please in future adverts mention who cheques should be made
payable to. I have written it to Fred Publishing - I hope that's
not a problem.
BM Reply to Ton Voon
Yes, good point. Please DO make cheques out to FRED PUBLISHING.
I suppose there should be something in the adverts, I'll have to
see about that.
I'll pass your little query on to Brian Cavers. - BRIAN
Letter from Toby Cooley
Dear Sirs,
Included in various disk mags there are screens that have been
converted from the standard Amiga IFF picture format. I own an
Amiga 600HD (cue trumpets) and would like to do some of this
myself.
Do you supply or know where I can obtain the hardware/software
that enables this process?
Ta. Up the SAM, etc...
BM Reply to Toby Cooley
Well. What a coincidence. There we were, Colin and myself,
discussing this very thing, and suddenly as if by magic - a
letter asking how to convert Amiga screens! Dear oh dear. It
does make you wonder if there just maybe is something "up there"
after all planning these things. But enough background and onto
a solution to your problem.
There is a way to convert screens, but at the moment it's very
fiddly indeed, and requires umpteen different utilities on both
the SAM and the Amiga. FRED Publishing, however, is hoping to
release a nice user-friendly all-in-one package for the Amiga
which enables you to save screens directly to SAM disk and then
convert them in one simple process. Clever eh? It's not definite
at the moment, however, and if it falls through, we've received
a nice explanation from Nigel French which contains details of
all the utilities you need. If the deal does fall through, we'll
print that sometime.
BM Reply to Toby Cooley
Getting onto something else now, were you one of the people who,
like me, bought an A600 and then half a sodding hour later
Commodore released the A1200 FOR THE SAME PRICE!! Just slightly
annoying wasn't it? Oh, the things I would say to the bloke in
charge of Commodore if they weren't surrounded by more bureau-
cracy than your average European community...
Oh yes - what exactly is the caper with the calling me "Brian
M(something)" at the top of your letter!? I get the distinct
impression that you don't seem to know what my name is, young
Toby C(something).
BM No Pain, No Gain
Yes! It's happened! A whole issue has gone by with no mention of
Robert Pain! Hurrah!
Actually, we did get a letter from Mr Pain, but decided not to
include it, just for a laugh like.
Sorry about my little habit of constructing fatuous puns out of
your surname, Robert, but it really is SO tempting. I expect you
find it a right pain sometimes (oops). Chuckle. Do you mind if I
ask what sort of printer you use? It's very good, anyway. I'd
guess it's either a daisywheel or a laser, and if it's a laser
what the Hell have you only got a SAM for? Surely an Archimedes
is more appropriate for such an affluent type? It's like having
a 24-bit colour card for a BBC micro (which, sadly enough, my
school still uses. Tragic huh?).
Don't worry readers, I expect we'll let Robert have his say next
month. Ho hum. That's it from the Letters section this month.
Goodbye. - BRIAN
DIY Space Invaders: MC Tutorial (Ctd.)
Well, by now you all should be going stupid after playing a game
that you can't see. And the most adventurous of you would have
written your own print routines. So for those that have, see how
they compare to mine, and for those that haven't: stop here and
go and write some (just for the fun of it)!
For all you people in the world the disk has for you :
File name - Discription
IN-BCK.SCR - Backdrop for the game
IN-TXT.PT3 - This text
IN-SOURCE - Comet source file (third installment)
- Due to the content of Chris's little background screen (I'll
leave it to your imaginations), we're unable to include it.
Don't worry though, any screen you can think of will do just as
well. And a large tut tut tut to you, young Christopher. - BRIAN
Game Theory
~~~~~~~~~~~
We will have to engineer the print routine to setup and store
the screen address, So when we loop back round we can replace
what was originaly under that sprite. There must be to locations
for this as we are flip screening, So replace address for screen
one will be totally different for screen two (if the sprites are
moveing one pixel or more every two frames).
To save time and memory we will not be storing the background;
instead we will have a copy of the backdrop (COPY.SCR) and our
screen address+&8000 will give us our copy from address. That
makes thing easier doesn't it.
Some of the sprites will have to be clipped as they enter and
exit the screen. This will be done in away you probably have
never thought of doing (or thought but never managed it. Or HAVE
done it. If you enter into the third then you should not need me
to tell you any more).
Right, to clip at the edge I am going to use 15 different print
routines. Seven will print from 7 to 1 bytes at the left side of
the screen, seven more for print 7 to 1 bytes at the right side
of the screen, and one for print all 8 bytes any where else on
the screen.
The theory for this is as follows:
If xcoord <128 and >121 then print width-(xcoord-120) bytes
to the right of screen at current xycoord.
If xcoord >128 and <&f9 then sprite of screen x
If xcoord >=&f9 then print width-(xcoord-&f9) bytes to the
left of the screen at current ycoord x=0.
"Well," I hear you cry, "how will this help us?". Simple; all we
do is a check just like the following :
LD HL,(XCOORD) ;GET XYCOORD FOR SPR.
LD A,L ;LET A=XCOORD
CP 128 ;TEST IF COMMING ON LEFT SIDE
JP C,RIGHT ;SPRITE MUST BE CLIP RIGHT OR
;PRINT ALL
CP &F9 ;TEST IF COMING ON LEFT SIDE
JP C,PRINT.RET ;SPRITE IS OFF SCREEN ON X
;SO NO PRINT
SUB &F9 ;SUB &F9 SO A=0 TO 6 FOR
;AMOUNT OF CLIP TO LEFT OF
;SCREEN
LD E,0 ;SET SCREEN X TO 0 AS THIS IS
;LEFT XCOORD OF SCREEN
LD D,H ;SET D TO YCOORD OF SPRITE
ADD A,A ;A*2
LD L,A
LD H,0 ;HL=CLIP AMOUNT*2
LD BC,L.TABLE ;ADDRESS FOR CLIP LEFT PRINT
;ROUTINES TABLE
ADD HL,BC ;ADD CLIP AMOUNT
LD C,(HL)
INC HL
LD B,(HL) ;BC=PRINT ROUTINE ADDRESS
JP DO.PRINT ;GOTO MAIN PRINT SETUP
RIGHT:
LD E,0 ;SET E TO ZERO SO IF NO CLIP
;WE WILL GET PRINT ALL 8
;BYTES ROUTINE ADDRESS
CP 121
JP C,NO.CLIP.R ;IF LESS THAN 121 THEN WE CAN
;PRINT 8 BYTES WITH OUT GOING
;OF SCREEN
SUB 120 ;SUBRACT 120 AND NOT 121 IS
;BECAUSE RIGHT TABLE STARTS
;WITH PRINT ALL 8 BYTES
;A SHOULD HOLD 1 TO 7.
LD E,A ;SET E TO A SO AND DOES NOT
;CLEAR CLIP AMOUNT
NO.CLIP.R:
AND E ;IF NO CLIP THE A WILL EQUAL
;ZERO, BUT IF WE MUST CLIP A
;WILL BE UNAFECTED
LD E,L ;SET E TO XCOORD OF SPRITE
LD D,H ;SET D TO YCOORD OF SPRITE
ADD A,A ;A*2
LD L,A
LD H,0 ;HL=CLIP AMOUNT*2
LD BC,R.TABLE ;ADDRESS FOR CLIP RIGHT PRINT
;ROUTINES TABLE. REMMEBER
;THAT ZERO WILL GIVE PRINT
;ALL 8 BYTES ROUTINE
ADD HL,BC ;ADD CLIP AMOUNT
LD C,(HL)
INC HL
LD B,(HL) ;BC=PRINT ROUTINE ADDRESS
DO.PRINT:
RL E
SRL D
RR E ;DE= SCREEN ADDRESS
LD HL,S.SCRONE ;HL SET TO REPLACE ON SCREEN
;ONE ADDRESS
IN A,(LMPR) ;GET CURRENT SCREEN BANK
;SET INTO LMPR
AND 31 ;KEEP ONLY BANK BITS
CP SCR.ONE ;IS IT SCREEN ONE
JP Z,SET.REP ;YES SO GO HERE
LD HL,S.SCRTWO ;IF NOT SCREEN ONE SET HL
;REPLACE ON SCREEN TWO ADR.
SET.REP:
LD (HL),E ;STORE REPLACE ADDRESS INTO
INC HL ;SCREEN INFO TABLE SO THAT
LD (HL),D ;ON NEXT TIME AROUND WE WILL
;KNOW WHERE TO REPLACE THE
;BACKGROUND SO SPRITE WILL BE
;ERASED.
LD L,C
LD H,B ;SET HL TO PRINT ROUTINE ADDR
LD BC,(S.SPRITE)
LD A,SPRITE.BANK
OUT (HMPR),A ;SET SPRITE DATA BANK HIGH
JP (HL) ;JUMP TO PRINT ROUTINE ADDR
;WITH BC=DATA DE=SCREEN
;these are the tables for the above checking and address to get
;the correct print routine address.
;GOING FROM LEFT TO RIGHT
;THESE ARE THE BYTES THAT
;WILL BE PRINTED (-=NO *=YES)
; 0 1 2 3 4 5 6 7
L.TABLE: DEFW PRINT.L1 ; - - - - - - - *
DEFW PRINT.L2 ; - - - - - - * *
DEFW PRINT.L3 ; - - - - - * * *
DEFW PRINT.L4 ; - - - - * * * *
DEFW PRINT.L5 ; - - - * * * * *
DEFW PRINT.L6 ; - - * * * * * *
DEFW PRINT.L7 ; - * * * * * * *
DEFW PRINT.A8 ; * * * * * * * *
R.TABLE: DEFW PRINT.A8 ; * * * * * * * *
DEFW PRINT.R7 ; * * * * * * * -
DEFW PRINT.R6 ; * * * * * * - -
DEFW PRINT.R5 ; * * * * * - - -
DEFW PRINT.R4 ; * * * * - - - -
DEFW PRINT.R3 ; * * * - - - - -
DEFW PRINT.R2 ; * * - - - - - -
DEFW PRINT.R1 ; * - - - - - - -
If that doesn't make sense then you either read it in two
seconds or it didn't sink in so re-read. If after re-reading
more that 10 times GIVE UP and mess with the code, 'Cause all ya
gotta know is that it works. STEVE TAYLOR will PROBABLY explain
this a little better than I could. How about it then Steve..?
Well. Four pages explaining how to clip to the left and right,
and you still don't know how to clip the top and bottom of the
screen. So here goes another four pages.
The screen address mode we are using (xycoord to screen address
using the ariffmatic tecnik) gives us one other advantage: this
is that the address will never go over &7FFF, So if we take the
high byte of a screen address and AND it with 127 then compare
with &60 (first pixel line of bottom of screen). If a carry
occurs (C) then line on screen. If you have your screen in HMPR
change the AND to OR 128 (always set bit 7) and compare with
&E0.
So our print routines will have one more addition to them and
they will look something like this (we should hope) :
Entry : BC=DATA ADDRESS
DE=SCREEN ADDRESS
PRINT.A8:
LD L,C ;FASTEST WAY TO LD HL,BC
LD H,B
LD A,16 ;DEPTH OF SPRITE
LD B,0 ;WE WANT B=0 AND WILL NEVER
;CHANGE B SO MAY AS WELL DO
;IT BEFORE LOOP
PRINT.A8.L:
EX AF,AF' ;STORE DEPTH COUNTER
LD A,D ;GET SCREEN HIGH BYTE
AND 127 ;MASK OF BIT 7
CP &60 ;ARE WE OF BOTTOM OF SCREEN
JP C,PRINT.A8.N
LD C,128 ;WE ARE OF SCREEN SO MAKE
;ADD TO NEXT SCREEN LINE=
;SIZE OF MODE 4 SCREEN LINE
LD A,L ;GET DATA LOW ADDRESS
ADD A,16 ;ADD SPRITE WIDTH*2
;*2 BECAUSE DATA+MASK ARE
;STORED SO NEED TO GO PAST
;ALL DATA FOR THAT LINE
LD L,A ;REPLACE BACK INTO L
JP PRINT.A8.N2
PRINT.A8.N:
LD D,A ;D=A INCASE D>=128 (IN HMPR)
;THEN WE WILL PRINT AS MANY BYTES AS NEED LIKE THE FOLLOWING
LD A,(DE) ;GET SCREEN DATA BYTE
AND (HL) ;MASK WITH MASK BYTE
INC L ;INC. TO DATA BYTE
OR (HL) ;MIX WITH DATA BYTE
INC L ;INC. TO MASK BYTE
LD (DE),A ;STORE NEW BYTE TO SCREEN
INC E ;INC. TO NEXT SCREEN LOCTAION
LD C,128-NO OF INC. TO NEXR SCREEN LOCTAION
PRINT.A8.N2:
EX DE,HL ;LET HL=SCR,DE=DATA
ADD HL,BC ;ADD TO GET TO NEXT SCR LINE
EX DE,HL ;LET HL=DATA,DE=SCR
EX AF,AF' ;RESTORE DEPTH COUNTER
DEC A ;DEC. IF NOT ZERO LOOP AGAIN
JP NZ,PRINT.A8.L
JP PRINT.RET ;JUMP BACK
Thats about all for that. The source will also help but I don't
think I can explain the print routines any more. So mess with
them and watch the effects if you cock it up (one hopes you
don't).
One last theory is we will not have to clip replace the
background because, if we are at the left our screen address is
set to zero on x, and if we are at the right we only replace on
the next line down and we needn't worry about that. All we do
have to worry about is clipping on the ycoord.
Screen Area Source Explaintion
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
****************************************************************
To mix this month's source with the source you should have saved
last month, all you do is load in the source you have saved then
merge in this month's source. Then, find the label MERGER; this
will take you to the start of the merged source. Then follow and
act on the text messages there.
****************************************************************
As most of the source has already been covered in the
GAME.THEORY (the sprite CLIP-PRINT routines), I only have a few
routines left. These are those routines:
Screen Extras
~~~~~~~~~~~~~
This is the two calls that go into the area labled SCREEN. All
we do is REP.SPRITES for the current LMPR, then PRINT.SPRITES
onto the current LMPR setting.
Print Sprites
~~~~~~~~~~~~~
This is the main loop for printing all the non-interrupt
sprites. We start off by putting MAIN.BANK into HMPR (this is
where our sprite list is). Then we copy in the sprites to the
screen table S.XCOORD, Which is exactly the same as M.XCOORD
(used by SPRITE.CONTROL), but has an "S" for screen and not an
"M" for main.
Then test if sprite is alive (S.STATE <> -1). Then do the checks
for clipping on the x plan (as in GAME.THEORY). When a print
routine has finished it jumps to PRINT.RET, This is when we set
HMPR to main.bank (printing a sprite requires us to put
SPRITE.BANK in HMPR), then copy back the info table to the
sprite list. This is done so that the new replace address for
that screen is stored and not lost. Then we repeat the above
untill all sprites have been printed and return.
Replace Sprites
~~~~~~~~~~~~~~~
This is the main loop for replacing all the non-interrupt
sprites (DEJARVOUS) background (to erase the image). As
explained in the GAME.THEORY, we effectively print from one
screen (COPY.SCR) to our screen in LMPR an 8 bytes by 16 bytes
block. This is slightly different to the print routine in the
following points :
1: We don't have to copy the info table to the screen area, as
we only need two bytes, so use the Index register IY for speed
(usually Index registers are a slow way to get data).
2: We cannot check if alive or not, because when a sprite dies
we still have to erase the sprite on the screen before it died
(That sounds Weird).
Another way of putting it is like this: We print last frame of
explosion on screen one and switch screens. Now we are on screen
two and sprite has died (reached the end of explode sequence),
so we kill sprite. Sprite is dead before we erased it on screen
two and we still have an image on screen one to erase.
3: We don't have to mask anything so a simple LDI instruction
will do.
After all that our main replace should look somthing like this:
Entry : HL=COPY SCREEN ADDRESS
LD A,16 ;DEPTH OF SPRITE
LD B,0
REPLACE.L:
EX AF,AF' ;STORE DEPTH COUNTER
LD A,H ;GET SCREEN HIGH BYTE
AND 127 ;MASK OF BIT 7
CP &60 ;ARE WE OF BOTTOM OF SCREEN
JP C,NO.REP
OR 128
LD H,A
LD E,L ;THIS MAKES THE ERASE ADDR
LD D,H ;EQUAL THE COPY ADDR, BUT
RES 7,D ;BUT WITH BIT 7 RESET AS
;SCREEN IS IN LMPR ONLY
LD C,128 ;set 'C' here as LDI decrease
;BC and as B will always = 0
;this gives us our next line
LDI ;THESE COPY 7 BYTES FROM HL
LDI ;(THE COPY SCREEN ADDRESS),
LDI ;TO DE (ERASE SCREEN ADDRESS)
LDI ;
LDI ;THEY TAKE 16 T-STAKES EACH
LDI
LDI
LD A,(HL) ;LAST BYTE LIKE THIS 'CAUSE
LD (DE),A ;IT SAVE 2 T-STAKES
NO.REP:
ADD HL,BC ;NEXT LINE ADD
EX AF,AF'
DEC A
JP REPLACE.L
And that covers the sprite replace. It's simple, and not as fast
as Stefan's builder, but we can clip at the edges of the screen.
And we can print as many sprites as we want with the same
routine.
Screen Tables
~~~~~~~~~~~~~
All we have this month is the screen copy area for sprite
information and the clip left (PRINT.L.TABLE) and clip right
(PRINT.R.TABLE) for address the required print routines.
Merge Data
~~~~~~~~~~
This is for loading in the background screen to COPY.SCR bank
when we assemble. You can load any screen you want here, but
this is a little screen I did (unless Colin's changed/removed it
for possible legal reasons) (Damn right there Chris!! - BRIAN).
Well after that the game should run and you should be able to
see what you've been shooting at for the past month.
"What have you got for us next month then Chris?" Glad you asked
that as most of you think that the game is now finished (yes
COOKIE I mean you). Most of you out there can already do what I
have done (Be it better or worse), but then you need to add the
end bits, and yes I hate doing these as well. So thats it: the
end bits.
So happy shooting the Invaders and leave some alive for next
month PLEASE!
Chris J. White
Converting Soundtracker songs to ETracker
Welcome once again to a piece of typing done by me. This time I
will not be writing about sprites, that would be rather boring
would it not? If you read the articles by Steve Taylor, Chris
White and myself on sprites you should know everything anyway.
On to business, this article concerns the conversion of Sound-
tracker song files to the ETracker module format. From now on I
will be referring to Soundtracker as ST and ETracker as ET
(phone home). Having had Soundtracker on my Spectrum (and as a
SAM conversion) and now having ETracker, I was interested in
converting the tunes from ST format to ET format. After all, a
music chip is not the main factor behind a tune but the musician
is and there sure have been some brilliant tunes on the Speccy.
First of all I had to figure out how everything was stored in
both formats. The formats were of course pretty different,
although luckily they both work according to a similar system.
See the end appendix at the end of this article for a list of
what is stored where and how if you are interested.
Next up was writing a program to convert ST to ET. For this,
still experimental stage, BASIC is ideally suited because it
usually does not give amazing crashes for little mistakes
whereas my assembly code always does. After I had got the main
conversion bit up and running it was time to write this in
assembler (with COMET of course) because making little changes
to the conversion routine and trying it out was taking too long
(think big, think at least four minutes).
The coding was a doddle (almost) and once more machine code
could show what it was made of. Under a second to do what BASIC
took four minutes to do. In machine code I could then go along
and experiment with some more conversion chores to let the code
evolve to what it is now.
The program consists of a friendly BASIC bit and a hostile code
bit, this last bit is stored in a string and poked into memory
upon loading. All the converting is done by the code, all that
the basic does is ease loading and saving of files.
Now let me tell you about the differences that will occur
between an ST file and an ET file because converting these would
require extensive coding whereas a human brain can solve these
questions in the blink of an eye.
1. The AY-8912 chip (128k Spectrum) has a non-linear tone ladder
the SAA-1099 (SAM Coupe) has a linear one. This makes it very
hard to calculate what the tone deviation of an instrument
should be. As the range on the AY is 4096 tones and on the SAA
2048 tones, the converter simply halves the deviation. For
normal instruments this works fine, but for drums (which are
simply a few large tone decrements) the deviation is still too
big causing the tone to wrap round to a high note. To fix this,
manually decrease the amount of deviation. Once you have a good
drum it is a good idea to save this so that you can simply load
it in the next time you have a drum to convert.
2. Rests: this function works differently on ET. With ST a rest
turned off a note, but kept the current instrument and ornament
active. On ET the command 6 also turns off the note but it also
clears the instrument and ornament. I chose to use the 6 command
anyway. If there are more notes without an instrument or
ornament then you will have to change the first ins/orn after
the 6 to what came before it.
3. Modulation: some music on ST made use of modulation to make
the bass sound more bassy. As the way this works on the SAA and
the AY is so different this is not converted. If an ST
instrument only uses modulation (no noise, no tone) then you
should turn the tone mask on again to still hear something. A
very easy way to make the bass deeper is to copy the bass- line
to another channel and then transpose this channel down (or up)
with 12 semitones.
4. Ornaments: on ST there is a function to turn off an ornament,
to do this on ET I play a so called null ornament, this is
ornament G.
5. Repeats: if you had a loop in an instrument, the ornament
which is being played gets looped in the same way as the
instrument. In ET the instrument and ornament loops are totally
independent. To half solve this problem the converter looks for
combinations of instrument/ornament in which the instrument is
repeated. The ornament attached to this instrument is then also
repeated in the same manner. If however one ornament is attached
to more than one repeating instrument there will be a problem,
the loop of the last instrument found will be used. You can
manually copy this ornament to the free slots and manually
change the loop and occurrences of this ornament in the song.
6. White noise: with the AY you can have 32 different degrees of
whiteness. On the SAA you can have 4096, but when converting
from ST to ET it is much easier to simply use the built in chip
noise frequencies (3 degrees) so the 32 degrees are brought back
to 3 degrees.
7. Speed, this is contained within the song data in ET (making
it variable) whereas it is not stored within the song data in
ST. The speed is put in the first played pattern (first pattern
in song table) in channel D (command 3 followed by speed).
Well this concludes this bit of info, I hope it enlightens you
in some strange and obscure way. I also hope that you enjoy the
music and I would like to thank the musicians responsible for
the Soundtracker songs, unfortunately unknown to me.
Stefan Drissen, [redacted] Tel: 073-414969
SD Appendix A: Soundtracker file format
====================================
song file:
00000: instrument data (15 instruments)
01950: song table (256 entries)
02462: song length
02463: unknown
02495: ornament data (15 ornaments)
02975: unknown
03007: speed
03008: pattern length
03009: patterns
instrument data: 15 instruments of 130 bytes each
000: volume (0-15)
032: noise mask, tone mask and noise frequency
bit 7 bit 6 bits 543210
1=noise off 1=tone off 0=low, 31=high
064: tone deviation (-4095 to +4095)
(two bytes, low, hi), hi +16 is negative deviation
128: repeat
129: repeat length
The repeat system requires further explanation, an
instrument is played (all 32 parts) and then it
restarts at repeat, then repeat length parts are played
and then back to repeat etc.
song table: 256 entries of 2 bytes each
000: pattern number (1 to 31)
001: height (2's complement)
song length: 1 byte
000: number of song table entries to play before looping
back to the first entry.
unknown: 32 bytes
just that.
ornament data: 15 ornaments of 32 bytes each
000: semitone deviation (2's complement -64 to +63)
unknown: 32 bytes
speed: frame delay till next note, 1 byte
pattern length: number of items in pattern, 1 byte
patterns: a pattern consists of pattern length lines, each line
has three notes (1 for each channel). Each note is
made up of three bytes. Patterns are stored one after
the other (the starting address of the second pattern
is thus dependent on the pattern length)
coding: first byte
bit 7 bits 6543 bits 210
1=rest note octave (0 to 7)
note: 2=A, 3=A#, 4=B, 6=C, 7=C#, 8=D, 9=D#, 10=E, 12=F
13=F#, 14=G, 15=G#
second byte
bits 7654 bits 3210
instrument command
(1-15) 15=ornament (other values for modulation)
0=no change 1=ornament off
third byte
bits 7654 bits 3210
for modul. if command=15 then ornament (1 to 15)
0=no change
Appendix B: ETracker file format
================================
Module file:
00000: instrument header (32 * 4 bytes)
00128: ornament header (32 * 4 bytes)
00256: song table (256 * 2 bytes)
00768: pattern lengths (32 * 1 byte)
00800: song length
00801: song loop to
00802: patterns (32 * max of 3*6*64 bytes, 64 = pattern len)
37666: ornament data (32 * 256 bytes)
45858: instrument data (32 * 1024 bytes)
78626 = total length
instrument header:
000: loop from here
001: loop to here
002: stop here
003: unknown
ornament header: identical to instrument header
song table:
000: pattern (0 to 31)
001: height (-128 to +127)
pattern lengths
000: length of pattern (1 to 64)
song length: last song table entry to be played
song loop to: entry to go to after last entry played
patterns: a pattern consists of the amount stored in the pattern
length belonging to it lines. A line consists of six
notes, each note is coded with three bytes. Patterns
are stored one after the other according to length.
byte 1
bit 7 = hi bit instrument
bits 654 = octave
bits 3210 = note (0=C,1=C#,2=D,3=D#,4=E,5=F,6=F# etc)
byte 2
bits 7654 are low bits of instrument
bits 3210 are low bits of ornament
byte 3
bit 7 = hi bit ornament
bits 654 = command
bits 3210 = parameter for command
ornament data:
stored as deviation in semitones (-128 to +127)
instrument data:
stored as 256 entries of 4 bytes
000: bits 7654 left volume (might be the other way
bits 3210 right volume round)
001: bits 7654 unknown
bit 3 = tone on
bit 2 = noise on
bits 10 = noise frequency. 2=low,1=middle,0=high
002: deviation (low, hi)
hi +128 is negative deviation
And that's all folks...