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Walker's Way Logo

Diary of a Game - Citadel - Part 7

Many, many thanks to Philippe Lesire for scanning and OCRing the Walker's Ways from issue 46 to 52.

Issue 48 - April 1989

Thursday 5th January After a surprise call from Kati asking if I'd like my music demo included in the next cover mounted cassette, today was spent collating a new version. After all, the existing one's now six months old! (I'm pleased to have a legitimate excuse to spend some time updating it). To be able to feature some of my latest commissioned work, I had to get permission from the companies concerned - after all, the pieces become their copyright once delivered. In fact everyone was keen for a bit of extra publicity, so I hope you enjoy listening to the demo on Issue 50 as much as I did creating it!
Friday 6th January Right. Time to get rid of these bugs. The mobile alien guards still have a tendency to get 'angry' if they can't get to you because of an intervening object - I spotted several of them earlier today battering themselves against a wall in total frustration. Others kept insisting that they'd seen me somewhere else, and wandered off in the wrong direction. Whoops! I finally traced the problem to the routine which calculates the player's current position in the city - it still updated with each joystick move; even when a wall forced to a stop and overrode the joystick. Everytime I collided with a wall my apparent position was getting further and further away from reality! (I've got to keep taking the tablets).
Saturday, 7th January Clever blighters these aliens, Not only will they aim accurately at the spot that you are heading for (rather than where you are) but after today will only fire if the security hazard (you) is in the line of fire. Different directional patterns for each category are now in and debugged; some guns for instance only fire horizontally or vertically - these are very useful for the protection of corridors! Others fire diagonally only (crossfire) which leaves others free to attack in eight directions. The upshot of all this is that you can now discern 'safe spots', out of the line of fire of static guns while you decide how best to proceed, and designing the placement of static gun emplacements can be more devious.

Improvements to the tracking system for mobiles now allows them to select the best direction, to allow them to get as close as possible to the player without colliding with each other's security systems (they've been going to evening classes to sort it all out!) This means that they can now surround you without getting in each other's way, although if one gets stuck at the back it will keep dodging backwards and forwards trying to get through the crowd!
Monday 9th January A telephone call from Activision today - they are happy for me to use a musical piece from a Secret Project on the new music demo (Hooray!). Having added the final piece it's time to compile the lot, compact it and prepare the disk to send to ZZAP! Towers. The packaging of disks always seems to take longer than expected to do properly - and I'm a bit cautious since the time a certain posman bent one of my envelopes (and disk) in half to wrap round a pile of letters, even when it was encased in corrugated cardboard. There wasn't much chance of loading that! (What a crease. Groan!)
Tuesday 10th January I had a big argument with two of my disks this morning. These two were brand new a short time ago, but they've caused me problems already, and this time I told them in no uncertain terms what I would do it they refused to display the directory again (I reminded them of a certain Basil Fawlty). They didn't heed the final warning, so I tore their inner disks out through the little slot in the jacket and then jumped up and down on them, which made me feel a lot better. Let that be a lesson to them both!
Thursday 12th January Time to do the dreaded yearly accounts. All the receipts kept during the last year need to be entered into my computerised indexing system, which then produces all the totals spent in each category (such as telephone calls, stationery, etc.) BORING! At least I keep a running total of all my income - it needs to be a running total to stop the bailiffs catching up with me!
Friday 13th January After hearing of the possibility that CHAMELEON maybe accepted for release in the United States, various modifications needed to be made to the code to ensure that it will run on the American NTSC television system, which has 20% less interrupt time. Since two years have since elapsed I'm very glad that I keep folders of such copious notes for each project - I wouldn't fancy trying to work out from scratch (although no doubt a lot of scratching of the head would be involved).
Monday 16th January Remember the story intro to an earlier diary? '... Each defence had been cunningly contrived, and no outward sign of danger was apparent, even on close inspection. There was one consolation only to he 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.' The time has come to start adding the big twist overriding selected security installations (traps to you!) to aid you in your escape from the CITADEL.

Off to a flying start today (literally). The time has come to implement the capture probe. As well as onboard weaponry, MONITOR has the handy ability to launch a probe which can override a targeted trap (mobile or otherwise). How to do fancy:
a) Reprogramming static defences to attack enemy units!
b) Overriding moving aliens for use as remote assassins!
c) Disabling moving aliens to provide strategic barriers!

At the end of a rewarding day continuous holding of the fire button now launches the capture probe, which can be freely moved anywhere on the screen. Releasing the fire button cancels this and returns control to normal weapons.
Tuesday 17th January An annoying little bug took more tracking down than expected. Sometimes an active trap would self-destruct when going off the edge of the screen. Apparently it thought it had collided with a wall! These security systems are less intelligent than they seem. As quite often happens, although elusive, the bug was completely cured by a little check - only two lines of extra code.

Yesterday's way of entering capture mode proved confusingly unworkable in practice, since bullets are fired by holding the fire button and then pushing the joystick in the required direction. All too often simply waiting in ambush for approaching mobiles caused the player to enter capture mode accidentally. A new system has been added that waits for two quick jabs on the button, but aborts if the jabs are too far apart. Much safer!
Wednesday 18th January Another tiny bug eradicated. The effect was occasional corruption in a particular part of the city floor - the prime suspect was overrun in the mainline routines (simple running out of time to plot the next screen display). After some detective work, narrowing down the problem by bypassing routines one by one (always the best way to start in these cases) the cause turned out to be a missing RTS instruction at the end of the alien firing routine! Funny things these computers.

Right. On with the capture probe. I want to get the effect of one of those controls on hi-fi's that 'click' into place giving a smooth 'grab' when the probe is close to a possible target. It is unfair to expect the player to position it exactly over a sprite - especially if the target is moving at the same time! After thinking it through carefully I opted for the probe being forced to match the position of a target closer than four pixels, and held for a short time. In practice this worked very well once 'tweaked' for feel - as you move the probe about it latches neatly onto each target it passes (when the probe will also flash to indicate a capture) and allows the player to target the probe quickly and reliably.
Thursday 19th January Start of capture probe effects. Any captured trap is now immobilised and its weaponry temporarily disabled. This allows you to concentrate on taking out other active traps when several are attacking simultaneously. It also proved useful for creating a temporary barrier to hide behind when a group of mobiles attacks. The main routines to follow will allow the player to use a captured mobile as a 'remote' device which mimics your firing and movement patterns, but also provide independent movement when needed. Since alien fire will be stopped by your new temporary ally it promises to be a valuable addition.
Friday 20th January In keeping with the boardgame strategy elements I finally added more colour to the cities by producing a chequered floor tile pattern in alternate colours that also makes it even easier to think in terms of 'squares', since proximities have become so important in the triggering of traps and equipment. This change also proved to have several very useful side effects. All the sprites now look 'crisper' against the simpler background with no harsh black shadows (it suddenly dawned on me that this is one reason why the ELIMINATOR sprites look so good on the 16-bit machines). The other unexpected improvement was the explosions, which now look more colourful.
Saturday 21st January A new design of sprites for an energy emplacement sprang out of the editor today, and a new modified system for the trapdoor sprites finally allowed all closed traps to use yet another colour in the background. After all this chopping and changing there are now five main colours on the screen at all times, and with the traps themselves in a selection of an extra five colours there are up to ten different hues displayed at once - without scrolling the colour RAM! It seems that in the past two days a whole new look has been refined - a product of lateral thinking (and just a bit of hard work!)
Monday 23rd January Since the new elements all hinge on the storyline a bit of background history might prove useful. The CITADEL is a vast construction of many city levels built by a long dead race. For centuries the forgotten corridors have lain thick with dust, totally unused and unoccupied - but for the still operational automatic security installations. These were programmed to detect any approaching alien intruder who strayed too close to their proximity zones.

The player controls the MONITOR - a Hoverdrone Mk IV remote module, which features flotation drive, quad peri-thrusters for directional control, and a built-in armoured display system that provide in-flight information. To escape from each city level involves not only defeating the many and varied alien defences, but also reprogramming the wall structures by means of switches which may completely change the layout of certain sections of the current city. Sending out the capture probe to examine different installations will provide information and collection of shield energy, extra usable weaponry, as well as the possibility of reprogramming the defences themselves to provide additional protection and an invaluable source of remotely controlled drones!
Tuesday 24th January Right. Time to add some directional animation. Since MONITOR is powered by motors which provide lift similar to a hovercraft, when moving the joystick from rest the drive 'powers up', providing flotation just above floor level, and peripheral retros then provide thrust in the required direction. The thrusters now animate correctly depending on joystick direction, along with the rise/fall motion for take off and landing, with suitable sound effects added. The built-in miniscreen will show in-game information and stay 'right side up' (it wouldn't be very readable if MONITOR rotated!) - this is a job for tomorrow (sounds like a good slogan for an SF mag. doesn't it?)
Wednesday 25th January The miniscreen burst into action at the end of a long bout of coding. Although only a single character in size, the screen has protective armoured doors which open when information is needed, but close to provide protection for the fragile display during combat. When the capture cursor is used it indicates the type of installation targeted, which is extremely useful for searching out energy pods or switches operating hidden doors.
Thursday 26th January Final touches to miniscreen included a flashing indication for the current target - E for energy, C for capture, S for switches and F for additional firepower. When the thrusters operate it displays an animated revolving symbol, and all should be completely readable even on 12" black and white TVs!
Friday 27th January After a chance thought about the possible additional weapons that could be picked up from selected traps, I ended up producing and implementing four new weapons, complete with pod designs! Apart from the one supplied at the start of the game, during the course of your travels you may come across a RAPID FIRE, TWO-WAY FIRE (great for strafing both sides of a corridor when in 'glide and fire' mode'), THREE-WAY FIRE (forwards and both diagonals either side of the current firing direction), and FOUR WAY FIRE (again with respect to the current firing direction). It really makes excursions into those little dead end corridors worthwhile if you emerge having a new weapon to play with!
Saturday 28th January After such a rewarding Friday the productive hypersurge continued as alien fade-ups were designed and perfected. Now, after a mobile-launching trap has opened, each mobile alien device emerges from blackness, slowly rising out of the floor and into the harshly lit corridors of the CITADEL!

It took a bit of time before the most effective sequence of sprite definitions evolved for the fade, but once complete for one design of alien, the rest followed quite quickly in the same style. When the necessary additions had been made to the source code the new version appeared on screen - I was well pleased!
Monday 30th January Only half a day today. The weapons pods needed some 'mods' to bring them into line with the other alien machinery and, since shield energy and weapons pods are collected by the capture probe, a design for an empty pod 'hangar' was also needed to appear when the contents have been used. This looks far better than the whole trap simply disappearing! And talking of that, I'd better run this diary through the spelling checker and then make it disappear into the post if it is to arrive on time. May the force be with you (and I don't mean the boys in blue!)

Issue 49 - May 1989

Want to learn about life, the universe and everything? Want to win friends and influence people? Well we can't promise anything, but entry into the CITADEL will help you on your way...


Wednesday 1st February First job this month is to update the on-screen CITADEL logo - I've been meaning to incorporate a smooth colour fade for some time now. To convert my design from theory into practice a mock-up program was produced which allowed three different colours to be altered on every scanline - a perfed test-bed for design! By the end of the day the in-game logo had emerged in its new form, with six colours fading through it in a classic 'airbrushed' look.
Thursday 2nd February Now to Incorporate the new logo into the game, together with a short routine to produce the same effect as my test-bed. It looks much more solid than the original design, and the fade is really neat (although I say so myself!) The only knock-on effect is that my NMI splits now judder alarmingly when sprites disappear beneath them. Back to the think tank for a modified version of the split routine.

These splits are a major annoyance (Grrr!). Every 8 scanlines the processor gets switched off for 40 cycles to give the hardware time to read in the next row of characters to display, and it's this that causes the timing problems when you're trying to judge changes that ought to be happening off the edge of the screen where on-one can spot them. To add to the confusion, any game that scrolls vertically moves these 40 cycle 'stops' up and down the screen. Then to further complicate matters, any sprites displayed stop the processor in its tracks for another 2 cycles each. Get the picture? Well, the problem was cracked in the end, but it took plenty of brain cells!
Friday 3rd February MONITOR's main armoury is a 'particle-beam' weapon which hurls out streams of energy globes. After an odd thought (and I do have quite a few!) I hit on a way to quickly detect which type of floor the globe currently occupies to allow the shading and shadow of the globe to change as it passes different colours in the cities. Just a small point but it only took half an hour in total.

The rest of the day was spent back in Sound Effects Editor, producing more new sounds and adjusting priorities to allow some sounds to be more important than others. After all, who wants to hear a wasted enemy missile impacting on a wall if your low energy alarm should be sounding? Answers on a postcard please. (Why does everyone keep saying that?)
Monday 6th February A bit of reorganisation allowed more moving baddies on screen. Although I allowed for four mobile sprites to be active, originally this included enemy bullets, and when four baddies had emerged from their hangars they simply stopped firing (not particularly menacing, that!) By adding some simple checks to the movement routines there is now provision for four mobiles and two enemy bullets simultaneously (as well as up to ten sprite traps on screen). In total CITADEL is running up to 18 sprites - the absolute top limit is six aliens across any single horizontal strip, since MONITOR and the capture probe always use the two sprites not grabbed by the multiplexor. With total control over all alien movements at once (I like for example the 'waves' of aliens in ARMALYTE) all 16 created by the multiplexor could be moving, and this will be used in some of the special 'secret rooms', such as storage hangars and laboratories. Wow!
Tuesday 7th February Today was a major tragedy. Our dog was run over by a van just outside the house after managing to open the front gate by himself. We rushed him to the vet, but he died in Belinda's arms before we got there, and in the circumstances I don't feel much like working for the next few days.
Monday 13th February Capturing enemy mobiles and controlling them needs a major think, as the joystick mechanics must be practical and foolproof (no disrespect intended to ZZAP! readers!) Two options are open at the moment: different control modes cycled through using the spacebar (OK, as the immediate danger from enemy bullets stops temporarily if you do - these security installations only attack if the player constitutes a threat), or a special sequence of joystick commands and obvious on-screen indication of your actions. Perhaps implementing both would be most useful, but with the option to deactivate the joystick method for those players who prefer using the spacebar (XENON really taxed my patience when it kept insisting that I wanted to fly when it was disaster to do so. Wiggling the stick is sometimes too easy to do by accident!)
Tuesday 14th February First job of the day - make another backup! Until you've got the sum total of six or more months of work on two or three disks you won't realise just how valuable these become. Apart from making back up copies of them about every week and hiding them in a safe place, programmers can also get quite fanatical about the safety of their working disks (I know I do!) Normally the source files and object code/graphics are kept on a separate disk, and these two travel with me wherever I go in a little black disk box (like a pair of duelling pistols!) Let's face it - it would be bad enough to be burgled, but losing your disks as well... Aaargh!!
Wednesday 15th February Visited my new accountant - and I really can't think of anything interesting to say about that! (with apologies to any accountants who may be reading this). Something struck me whilst looking round the software shelves later on (and it wasn't a passing ZZAP! reader!) Have you ever thought that looking at the boxes all lined up just isn't half as exciting as reading the reviews in magazines? I know I have! Even peering at the often microscopic screenshots is often no help at all in deciding whether to buy, especially if all inlays show the 16-bit versions (at least they now tend to declare which format is pictured - in the old days you could get a shock when you got home and saw what your version looked like!)
Thursday 16th February Right. Hands up all those who thought that they would be able to pick whatever weaponry they could find lying about inside the equipment bays of this long dead civilisation without paying anything for it. Sorry! Every item will take energy to grab and bolt on and the more powerful the weapon, the more energy needed to adapt MONITOR to the new environment.

Today the MINISCREEN was refined to display these energy requirements as well as the type of device captured by the probe. After two quick jabs at the fire button the capture probe will appear. While moving the probe anywhere on screen, any 'grabbable' item will pull the probe in to its exact position when close by, and then the MINISCREEN will indicate the type of item targetted (C=capture / E=energy / F=firepower / S=switch) alternating with the number of energy units required; all items so far need between 1 and 4 units.

  The current energy remaining to the player is shown in the form of a bar graph contained in the info pods (positioned at the top of the screen). The complete line-up of info so far (from left to right) is: Score, MONITORs remaining, current city, CITADEL logo, energy bar and current type of firepower. Now, instead of wandering about adding everything you can find, it's more useful to destroy the nearby defences and save the more useful energy pods and extra weapons until really needed.

Some of the weapons have also been improved, and the basic particle-beam weapon made rather weaker (why do I keep mistyping that as bean? - perhaps a vegetarian Freudian slip!) The 'add-on' weaponry now has a life of about 20 seconds continuous use, so when the low firepower alarm sounds you'd better start looking around for a new weapon - there's only two seconds of firing left in the one you've got. This encourages better use of resources and more interaction with the cities, and is also more like real life (yes I know it's only a game but that shouldn't stop some realism!)
Friday 17th February All those budding 'Rambos' out there will no doubt be pleased to learn that today saw an addition to the destruction of any static guns. Not only does the gun itself explode in a glorious technicolour blast, but now It also leaves behind a large crater! This proves a telling reminder of where you have travelled, and also stops any possible confusion between destroyed guns and the cavernous black exits from the launching bays of mobile aliens.

Ideas have now crystallised for controlling mobiles captured by your probe (just thought you'd like to know that). Oh all right I'll tell you then. There will be three capture modes:

1. MONITOR static. Joystick moves and fires MOBILE unit (ideal for softening up the area ahead and rather like the independent control of the 'Catalite' in WIZBALL).

2. MOBILE static. Joystick moves MONITOR and fires MOBILE (by pre-positioning the MOBILE you can protect MONITOR from attack by nearby traps).

3. joystick moves MONITOR and MOBILE together, and fires MOBILE (by pre-positioning the MOBILE this can provide protection in front, behind or any other position).

This probably sounds far more complex than it will feel in practice. Still, I'd prefer to offer plenty of variety - it's up to you whether you decide to use all the options! Every player will evolve their own preferred style of play - the bottom line is protecting MONITOR from destruction while searching the cities for the main exit, but this open ended approach allows many ways of achieving the same end.
Saturday 18th February My old friend Chris Payne arrived for a relaxing weekend - I don't think he realised that he'd be tied to the chair until I'd finished writing down all his comments and feedback about CITADEL! The most useful thing was watching a beginner play for the first time after only a brief description and demo by an expert player (me, you fools!) Once he got the hang of the capture probe the MINISCREEN display on MONITOR really helped in finding out what was what. The 'Glide and Fire' mode took a bit more getting used to, but once mastered does mean that you can dodge backwards and forwards whilst firing in a different direction. Practice makes perfect!

Overall response was very favourable, and first comment was 'This is great - and it feels really 'different' to play from other shoot'em ups' (which is what I wanted!) Specific thoughts concerned possible changes to the sprites. The enengy pod got confused with the static guns, and MONITOR's subtle engines which animate in each direction of travel weren't noticed for some time in the heat of the action (Repeat after me: I must be bolder with my pixels!) Another helpful suggestion was the addition of a demo mode which shows gameplay in a 'feature by feature' way. After all, how else will a beginner even guess at the variety of ways to explore and play?
Monday 20th February Start of the 'mods'. A new design of energy pod is now needed, but luckily the old one (which got confused with a static gun) can still be used after modification and different animation (as what else - a static gun!) MONITOR's engines were enhanced to boldly go where no engine had gone before, and a more stylised empty 'socket' produced to replace the original design (which remains in an equipment bay after a weapon or energy pod is collected).

A selection of small improvements were also made to the code as a result of my special guest's comments - the capture probe now grabs a bit more fiercely, and crashing into enemy units now drains more of your shield energy. After all, this isn't supposed to be dodgems!
Tuesday 21st February I don't believe this! After sitting down this morning a whole host of alien designs for new floor tiles appeared within half an hour which look like Aztec mosaics (well at lean I think so!) The screen designer (me!) is still suffering from shock - he normally likes to be warmed up thoroughly and have several cups of coffee before ideas commence. Still, if ideas want to come out when I'm not expecting them who's complaining? Not me!

After this great start to the day nothing seemed to be able to go wrong, and a neat design popped up in the sprite processor for a switch which will operate some of the secret doors - it looks like two contacts banging together (Oo-err!) All doors will blend in with the surroundings perfectly (looking just like another section of wall), but once a switch has been found and operated the affected area will shimmer for some seconds allowing you to pass through it. Effectively the cities will be formed from sealed chambers, each with its own secret entrance and exit. What better way to discourage intruders from exploring?
Wednesday 22nd February Another good suggestion for a subtle tweak gameplay has been the ability to change your mind after starting a move to an adjacent floor tile. In chess you can change your mind after moving a piece as long as you keep your hand on it (once you let go, that's it!) At the moment any move in CITADEL continues until the destination tile is reached. The next mod will allow free movement, but only allow stops in the middle of each tile. This way you can dart about, foxing the security installations who will always target their calculated destination, giving you more of a chance to dodge back out of the way. Sounds a bit complex, but I'm sure you'll notice the difference in practice!
Thursday 23rd February The next few weeks will see the doors leaping into action (or should that be shimmering?), and the long awaited (by me at any rate) ability of MONITOR to use lift shafts to sink into the city floors and emerge on the other parallel side of a city. This will really expand the gameplay and allow frenzied bursts of action in my 'level' editor to produce three dimensional mazes. Effectively all the basic elements will then be finished and levels can be completed by getting to the main exit (this may sound easy but there will be plenty of wheeling and dealing needed to even get as far as the second city!

Next month will also see the return of the music editor and the start of the CITADEL soundtrack. I'm hoping to fit in an in-game soundtrack option (wish me luck). Never will I forget the feeling it gave to DELTA! (Cue sunset and roll the final credit till next time).

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