C64 Logo
Back to the Main Page


Zzap! 64
  Zzap! History
  Zzap! Staff
  Zzap! Rrap
  Walkers Way

Hack to the Future

Your Commodore

Commodore User

Commodore Format

Your 64
  Best of 1
  Best of 2
  Best of 3

Misc (500+)
  Game of the Month

means the link is off site

Sign / View My Guestbook

Any comments, suggestions or questions, please email me at iain_black@yahoo.com

Walker's Way Logo

Diary of a Game - Citadel - Part 3

Many, many thanks to Philippe Lesire for scanning and OCRing the Walker's Ways from issue 36 to 40.

Issue 40 - August 1988

Month five: And in that dark place a silence grew; a silence that threatened to engulf all in its encompassing reaches. It hung in palpable folds about the fabric of the forgotten corridors, its dusty films smothering the former majestic glory. Indeed, it was no longer a place for wonder. Now only caution prevailed; for only caution could be advisable in a disused city that held untold secrets and horrors. Each defence had been cunningly contrived, and no outward sign of danger was apparent, even on close inspection. There was one consolation only to be savoured - for even as the traps could close their grinning jaws on the unwary, so also they held no loyalty to their designers, and could be turned against them.

Friday 13th May So reads the start of the storyboard for Citadel - yes, the new game has finally got a name and will enjoy a return this month to assembler teritory. In the meantime the music demo disk must be finished, duplicated and dispatched to interested parties!

A clove of garlic hangs from my monitor today, to ward off evil spirits. I shouldn't worry really, as 13 is supposed to be Walker's lucky number. Anyway, the primeval thoughts seem to have a positive result, as a new voice enters the music library - ethnic pan pipes. And no, I've not sampled them either! They fit perfectly into the start of piece three for the demo disk, which sounds dark and mysterious.
Saturday 14th May A picture of Martin with a disk!One channel of the SID chip went totally silent today, which caused a panic I can tell you! At first I thought the chip itself had gone faulty (Oh, calamity!) but on scanning the Programmers Reference Guide it turned out that I was a victim of the dreaded noise lockup. If the noise waveform is set and another waveform is switched on then noise may disappear altogether. The cure is to set and reset the Test bit of the relevant channel - the editor had now been modified accordingly. Quite a relief when everything chimed in again, but I suppose it is surprising that it hasn't happened before now.

After that bad start, things picked up when a new technique was found to produce large four note chords on one channel. Crossing my fingers, the next step was an obvious one - use it on all three channels! Suffice it to say that 12 note chords are now possible. Anyone who wants vast multi-layered soundtracks please bear me in mind - I'll be opening for business in about a week's time (mind you, by the time you read this I could be retired to Hawaii on the profits or living in a tent in Scotland to hide from the bailiffs - who knows?)
Sunday 15th May That screaming rock guitar has crept in again. Mind you, with a thundering bass line, drums and four note backing chords it sounds just right. Belinda caught me today playing an air guitar under headphones: head nodding. tortured expression on face, wringing imaginary notes from a nonexistent axe in total silence. Great fun - and it gets me in the mood for more music making!
Monday 16th May A day of tidying up. Several things needed sorting out with the player, like adding a control to quickly clear any section of sequence or track memory and resetting step pointers to return the operator to the beginning of the section (when I've allowed 128 steps in a sequence it can take a long time to get back to step one by hand!)

The tempo controls needed to be simplified - the byte values actually used don't really mean much, so the editor now uses a table of these peculiar numbers, which then allows tempo values from one to eight to be shown on the editor screen. These are much easier to understand - I've never been able to understand how anyone can work well when they constantly have to perform mental manipulations to understand what they are seeing and doing. An editor should be designed to act as a buffer between the actual data and the designer, so one can concentrate on the creative side - after all, if 20% of your brain is juggling with numbers, that's 20% not being used effectively!
Tuesday 17th May Back to the Armalite sound effects for some revisions. I've been told that there definitely won't be any more changes after this (!?), but as I enjoy the days at Exeter, and have been partly using this first SFX project as a means of honing my editor and adding features in the field, I don't really mind. One thing it has shown very clearly is that the only effective way to add sound effects to a game is to have a playable version to work from. Only by playing the game and hearing everything in situ can the effects be balanced and the 'feel' refined.

The most important sound of all in any shoot'em up is that of the player's main weapon. since you're likely to hear this almost non-stop during the game. There are a few games in my collection that have the monitor volume turned down during play, simply because this sound, although good by itself gives you a headache when you trigger it eight times a second! The new one for Armalite has a kick like a machine gun, but is well enough down in the mix not to overpower everything else, and when you stop firing it leaves the whine of a ricochet to add atmosphere.
Wednesday 18th May The sounds for Armalite are complete and installed! Everyone was well pleased with the remix and new main weapons - it just shows how important the final mix can be. We played a subtly 'tweaked' version of the game that lets you begin with a fully-equipped armoury on board. Much devastation followed! The final version of the super-weapon sounds really give you the feeling of power. as a five beam laser cuts a swathe through an entire wave of aliens with one searing blast! We celebrated by cracking open a new bottle of Nescafe, and I returned at midnight tired but exhilarated - my first freelance SFX project has satisfied customers!
Thursday 19th May Paul Cooper is arriving this afternoon to hear the new music demos. Apparently, word has already spread from Exeter yesterday about them (thanks guys!). so this morning I really must put together all the relevant files on one disk, and design a screen display and menu system, so that he can have a 'take-away'.

There's nothing worse than someone giving you a demo that needs a programmer to run it. I've received demos that require you to load two separate files by hand. and then type a SYS call before a single note can be heard. Most software houses won't have time to persevere further than the first piece in that format. First impressions are so important - just like reviews of a game in fact!

Paul finally arrived at 8pm. He really enjoyed the music - mind you, being able to play it back through a large speaker system does aid the presentation! I think I may have my first customer for game music shortly.
Monday 23rd May Time to get started with the duplication of the demo disks. About a dozen have now gone out to different places, and now the only thing to do is to wait for feedback. Back to the game!

During the lulls in musical inspiration the sprite editor has appeared on the screen several times, and now various new 'creations' have emerged, along with more of the gameplay elements. From the original city style and design to the present storyboard has been two and half months (not including all the time off to write the music player). I've been asked to prepare a proper storyboard for this project to explain everything that happens in the gameplay. As I'm used to letting the fine details evolve naturally, this requires some careful thought. The emphasis is on exploration and surprise, since a single 'step' may trigger a trap as easily as reveal a needed weapon or device.
Tuesday 24th May Just how many levels to include in a game is sometimes a more tricky decision than you might imagine. The careful design for my cities will allow me to store the graphics in a far more compacted fashion, allowing much more depth and variety for each level, but it has been decided to design 32 levels or less. which will allow many more features to be added to each, to provide greater depth to each level.

I suspect that many people took quite a time before they realised just how much was really crammed into Hunter's Moon - Citadel will have a free-running demo showing random sample levels, just to show the many features in action. I certainly know how disappointing it can be in a game to experience the opposite side of the coin. and find that there isn't as much as you expected. After having Mutants for a few days I couldn't wait to finally complete the first 16 levels so that l could see what new features came next. After playing for six hours non-stop my goal was finally achieved only to find - the same 16 levels with more difficult settings! A rather miserable evening followed!
Thursday 26th May Yesterday was spent at Ludlow, after a kind invitation by Julian for a mega game-playing session chez Rignall. We popped into the ZZAP! offices around lunchtime to see Gordon and Paul in action and tempted all the workers out to the Dog and Disk Drive (they didn't take much persuading!) After a round of orange juices (honest - they serve freshly squeezed ones that are amazing!), a bite and a chat (we put the software industry to rights as usual), Jaz and I got our joystick's out for a big session (our case comes up on Monday next!). Do you realise that more of this diary appears in brackets than out of them? Perhaps my word processor should be modified to insert them automatically at the beginning and end of each sentence.

During the afternoon my peeper's also got to view some of the many Compunet Demos that filter their way into the ZZAP! offices. There's one hell of a lot of talent out there, and I was suitably amazed. Some of the venetian blind raster effects on show were breathtaking, with imaginative character sets and effects, and suitably hacked music (I was glad to see that the composer was nearly always credited!). Incidentally, both Julian and Steve are also graphic artists (they showed me some of their impressive work), so look out for their names in some rather different situations in the future!
Friday 27th May Today saw the scribble factor in action again, with a little session of algorithmic design to determine how the sprites will detect walls and other solid objects, to negotiate their way around the city. This simply entails looking at the next character in the current sprite direction to decide whether to force a stop or explode (the sprite!). As my character set has always borne this in mind, all the 'safe' characters like floors are at the beginning. If you've ever used SEUCK you'll know what I mean!

In the evening some time was spent starting a new and more aggressive musical piece. This has a bass line that growls! It seems that it will be possible to 'multitask' the music writing and game programming successfully - when the game is in need of further inspiration the writing of some music seems to rejuvenate the grey cells very nicely!
Monday 30th May After a long diversion into different territory, today saw the first major advance into the Sprite Editor. Some time ago, you may remember, it was decided to redesign the main sprite. The definitive version is now complete- a mobile monitor (looking rather like a gold clad turbo-driven TV) which performs many different functions. Powered by floatation engines it can move freely around the cities, launch many varieties of weapons, probes and other devices, show information on its own screen, and even indicate the answers to certain questions by nodding or shaking its 'head'. All the animation for this is now complete. and I'm well pleased, since it will allow me to involve the player in much more interaction with the surroundings.
Tuesday 31st May Several telephone calls during the last few days showing interest in the music demo also resulted in a few tweaks to its presentation today. Firstly, the current piece being played is now highlighted (people can forget which one they are listening to, you know!) and instead of stopping dead when you press RUN/STOP the music now fades gracefully away. Also, since seeing the Compunet demos last week some time was spent incorporating some rainbow scrolling effects for maximum visual impact. After only one day, the overall 'oomph' factor is greatly increased for version two of the demo disk, available on demand shortly!
Wednesday 1st June Monday's sprites are now all set to be put into context in the game, with relevant animation. This proves fairly easy, but a bit more time is taken to think through animation routines for the 'aliens', since each will require different animation speeds and number of frames. There are four types of aliens so far - a couple of menacing metal insect species with waving antennae, and an unfolding 'eye' which throbs rather nicely. Each type will have its own character. Some will attempt to home in on the player whilst others will protect vital installations in the city (unfortunately they will also prove vital for the player!).
Thursday 2nd June Today saw some much needed thought into ways of introducing more colour into the cities. If you saw the rough screen shots in last month's diary you will know the look I'm after, but with much more colour and variety. Colour scrolling on the 64 is always a problem. as the processor is so slow that a large proportion of available time can be used up simply moving the screen about. All sorts of tricks can be employed. but the answer for many people is the Blue Peter method. This involves preparing a second screen of information already suitably scrolled in the required direction, so that when the fine scroll limit is reached, you simply whip out the one you prepared earlier (remember all those programmer's on TV?)
Friday 3rd June Start of the big scroll routine, including colour. Yes, I've decided to go the whole hog and shift the lot! This will mean less processor time for other things, but won't produce any noticeable limitations as long as things are carefully done. Most of the work will have to be done on paper first, since the algorithm requires optimising for minimum time (this one will take more time than any other routine!)

After an exhausting day on paper, the evening brought a welcome return to musical piece four, and following a fruitful session resulting in a good intro, a bit more coding concluded the day. A complete reshuffle of the music editor memory map allowed me to save all of the music files (voices, notetables. sequences and tracks) in one large chunk, to avoid having four separate operations every time an addition or modification is made. Every simplified operation releases more brain cells to produce more fresh ideas! So, with a numb brain and throbbing ears, but a more varied outlook, I'll wish you adieu till next time.

Issue 41 - September 1988

Martin opened his eyes. As he focused on the ceiling, he noticed the grey haze that filled the room. Damn, he thought. Another shakedown for the opposition. The smell of smoke awoke in him a feeling of hunger. He had not eaten since Thursday and now it was... hell! What day was it? He tried to work out how long he had been in the room but drew only a flicker of recogniflon from his normally alert mind. His senses, out of force of habit, quickly rallied in an attempt to make something out of this predicament. He got up and walked to the door which had been locked from the other side. Someone didn't want him to leave. Picking the lock with a paperclip, he opened the door a crack and glanced outside.


Sunday 12th June Another novel day. My joystick has needed some attention for some time now, and this afternoon saw the soldering iron out once again. Some years ago, when I worked in electronics, I was lucky enough to have the facilities of a machine shop to make a joystick to my own design. It uses rnicroswiches for reliability, but is unusual in that it is small enough to fit neatly into the palm of one hand and allow single-handed thumb operation of the stick itself if l lneed to access the keyboard with the otherhand (It was originally designed
for playing Star Raiders on the old Atari 400!). It still functions perfectly but the lead needed replacing afler being pushed and pulled for over 5 years, especially after coping with the ridiculous positioning of the joystick ports on the Atari 1024ST - plugging in the joystick involves tipping the machine upside down!
Tuesday 14th June Some time has now been spent on rewriting the main scroll routine. Since this single routine is more often than not the longest and most 'processor consuming' of any in a game, ways of reducing the time taken are well worth looking for. Most eight.way scrolling games use a smaller part of the screen as the playing window to reduce this problem. The most used method of scrolling is to shift the entire playing window in the direction of the scroll.byte by byte, and then plot a strip in the gap remaining after the rest of the screen has been moved along.

Hunter's scrolled the entire screen area in eight directions and this entailed devising some tricky routines which again used the Blue Peter methed of preparing a seecond screen while the first was being displayed. The only minor drawback in practice was the slight (4 frame) delay before moving off from the rest (a twelfth of a second might not sound like very much, but you do notice it). I have devised a new method for Citadel that will allow proper control with no delays. Watch this space!
Wednesday 15th June Sometimes modifying old routines can take longer than scrapping them and starting from scratch. The old scroll needs much hacking about before my new ideas can be implernented but I've started so I'll finish (pauses to mop brow). lnciddentally, the single routine that took most time towrite in Hunter's was the parallax star scroll - anyone who got Quedex on disk will have the early demo which had three layers of stars. In the end, by popular demand and for the greatest effect this was reduced to one layer scrolling at half speed and numerous additional 'twinkle' stars (and yes I know that stars wouldn't twinkle in space-
there's artistic licence!).
Thursday 16th June On with the scroll. This was a multi-tasking day, spent partly with the graphics editor (tweak tweak),.partly in the realm of sprites (nothing startling) and back into coding territory. No earth-shattering achievements and no disasters. Just an ordinary day in an ordinary week. Yawn.
Monday 20th June Well, the first stage of.the new scrolling routines is complete. There is now a static zone in the centre of the playing window, where the player sprite itself moves rather than the screen. When the edges of its zone are reached the screen.lackground starts to scroll. Unlike Alien Syndrome however the static area is only small. and you still get plenty of advance notice when.aliens arrive on the edges of the screen! The big advantage of this seemingly small cosmetic change is that underneath there is plenty of intelligent preparation going on, which allows me to retain a scrolling screen window as big as I need, rather than use a small cut down version like Gauntlet.
Tuesday 21st June Because of the way the new routines are structured, it should be a comparatively simple procedure today to add extra code that allows the player to get right into the 'corners' of the city. I chose this in Citadel as it gives you more feeling of coming to a boundary wall rather than the alternative which keeps the player in the centre of the screen but shows blank space beyond the boundaries (as used in Paradroid).
Wednesday 22nd June I spoke too soon! It took all of today to track down.and iron out the small multi-legged beasties (bugs to you) that inhabited the new 'corners' routines It would certainly make things easier to have a square screen like Quedex which avoids any game sprites going beyond the dreaded 'seam' where the horizontal sprite positions cross from 255 to 256. How ever, to do this means only using sprites in the right hand information strip as although you don't see it the screen is still scrolling about under cover of blackness! As Citadel. needs plenty of moving sprites in the cities, this method just isn't suitable.

The new 16 bit machines have a different problem with scrolling. As the high resolution multi-colour screens use so much more memory, moving it about takes up a lot of processor time, and since on the ST there is no fine scrolling every pixel of movement is separate and time consuming. This does allow any part of the screen to be fine scrolled in isolation, and the smaller the 'window' the less time it takes. Result - lots of square windows These really are ideal for eight-way scrolling games, as you get equal advance warning of aliens on the edge of the screen in any direction. Frustration soon sets in playing any game if you keep losing lives simply because you don't have time to react to something which hurtles into the screen window and sends you to your doom.
Thursday 23rd June Another venture into graphics territory. The screen shots included in the July issue were actually from a disk left at ZZAP! Towers at the beginning of April, so you should notice a few changes and improvements by now! The traps still need designing, and since there will be quite a few dotted around they will need to be fairly simple in design to avoid the overall effect looking cluttered. The floor designs from the previous screen shots were soon rationalised to provide greater contrast. Now, the cluttered floors are replaced by the cleaner lines of simple pastels for pipe-laden cities, but don't fret all those who like the original sculptured floors-they will stll lappear in cities which have simpler lines in wall design..All this helps widen the design gap between walls and floors, and thus provide a stronger visual impact.
Monday 27th June My main sprite, Monitor, has just emerged from the sprite editor looking rather more aggresive and now sports newly designed flotation engines which lift him slightly off the floor level rather like a hovercraft when he moves. Since his own miniature 'screen' will be displaying 'charge remaining', as well as other more esoteric functions, it has been decided (by my imagitiary committee) to leave directional animation out. This would confuse the 'screen' display when it rotated around corners!
Tuesday 28th June I'm off to a. meeting on Thursday, hopefully some music and sound effects work will emerge from it! To present the sound effects more easily a short demo was needed which allows a batch of effects to be named on screen and triggered from the keyboard selectively. This only took a couple of hours but the end result is far easier to demonstrate After my meeting I'll know whether the company concerned wish to place an (X) in the no publicity box. If not, then watch out for a further entry in this instalment of the diary.
Wednesday 29th June One thing to emerge from producing a storyboard is that once you have 'lived' with it for a bit it starts to take on a Iife of its own, and rather like boiling jam (?)all the choicest fruit bubbies rise to the surface. Many ideas have emerged that have since been refined or even discarded, and now a slimmed down version contains the essence of the gameplay. One important thing with any game is to keep the challengee even when you have played it over and over - I'm sure this is the reason why some games are discarded shortly after purchase. This all boils down (don 't worry! It's not going to be another jam analogy!) to the learning curve. Some games seen incredibly hard at first, and then you discover one 'trick' in the gameplay that lets you get a lot further. Others let you get a fair way in during the first few days,but then present a big stumbling block that stops you getting any further. I find that Motherships in progressive shoot 'em ups are often like this. Time and time again you get to the same level only to lose all your remaining lives trying to defeat the same obstacle Frustration!

Both these examples would have a learning curve (progress against time) with a big step in it. A classic example ot this is Space Invaders- once you realise that by picking off all the aliens at the extreme left or right it slows their descent and you suddenly find it possible to get much further The ideal learning curve is smooth or at least with so many small steps that in practice it amounts to the sarne thing This produlces a game that lets you progress a little further every time you play it and keeps you coming back for more My favourite game some weeks back was Xenon on the ST- unfortunately; although superb to play for several weeks I never got beyond Level Three. Even arriving there with every weapon on board and a full complement of ships there were so many gun turrets halfway through that.I always lost a ship, and with it of course all my hard earned weapons At that point the game was well nigh impossible to restart! Groan. I do know one person who can complete it but he is rather exceptional!
Friday 1st July The first music commission is now underway! Yesterday's meeting wetit well - old friends and new and a new sideline firmly established. In this turbulent industiy relying on one thing only can be fatal! Suffice it ti say I am now working for the 'SS' on a strategic simulation (mysterious eh?).

There are some strange 'quirks' in the 64. Although not everyone likes to use them, it is possible to do some strange things which seem quite often to be discovered. by accident. The 'infobars' used in Hunter's employed the much used sprites in the border trick and I was well pleased with the result The overall screen display became a lot better than normal, and allowed more on screen action. Some time was lost though, to a 'feature' in the SID chip, discovered when working on sound effects. The envelope controlling the attack, decay, sustain level and release time seems not to like being re-triggered if the sustain level is still maximum. This showed itself when occasionally a sound eflect would go completely silent when triggered twice in quick succession, and took some tracking down. The solution turned out to be simple in the end. If you never use the sustain level at maxmum (15) but always set it to 14 or lower the problem doesn't arise,. and I don't think anyone is likely to hear the difference, I lost hours tracking that one down!
Monday 4th July I have spent five hours trying to trace another weird effect in the SID chip - and with little success! Even studiing the waveform on an oscilloscope sheds no more light on a solution - only providing more evidence of the problem. The result of this quirk is that the basic sound of an instrument changes slightly when the envelope settings are altered. I've checked my code thoroughly, but am now convinced that it must be the SID chip (at least that's my story). Since the effects only happen when the envelope settings have particular values. It seems tthat having any decay or release time other than zero throws out other timings - although I can tweak instruments to sound 'right', in practice it shouldn't happen. Some days you work like crazy and have nothing to show for it at the end. Such is ithe life of the programmer (at least that's what I say when I'm feeling philosophical!).
Tuesday 5th July This morning saw me finishing off the investigation started on Monday into the dreaded SID chip bug. According to my 'scope', unless the release value of the envelope is zero the 'gate on' command (to start the envelope and hear the sound) is not accepted for 30-40 milliseconds, which means that part of the attack is lost complety! I've found no way round it, and unless you study the waveform I doubt that anyone would notice. Without a circuit diagraim of the SID chip itself I can do no more, but now at least know all the ways to minimise it.

After this untimely delay the new music project was continued in earnest dunng the afternoon and evening. Both the cassette loading music and the title tune are well under way, and I'm well pleased with them - very atmospheric! in fact I got so carried away playing synthesiser solos over the title track that I competely forgot that it was the humble 64 providing the backing!
Wednesday 6th July Today is the final entry in this month's diary, and also heralds the triumphant arival of my copy of Bionic Commando on disk after a wait of some weeks! The bionic arm is great and I must admit to losing a lot of work time today using it The difficulty level seems to be set about right at the moment although there are some very frustrating aspects - losing a life because someone drops on your head unexpectedly while you are hanging and waiting under a walkway is annoying and I would like to be able to shoot those dratted birds a bit more easily!

P.S. Thursday morning - Just before I send the diary off to Zzap! Towers can I amend yesterday's entry...? Bionic Commando is extremely frustrating, although still compulsive! (No! - Ed)

Visit Night Gem's Zzap Review of Citadel

Right Arrow
Continue Reading the Diary

Download the Game Here