Ghostbusters (Activision)

[tricky]

Are you thinking about actual speech support for the swram version, might even be smaller than the samples? Needs updating every frame, well, <25ms.

[ChrisB]

No actual speech support - all the samples are (afaict) speech of some description - I was referring to those.

[tricky]

I know but you could add it in the swram version or in place of the samples if you wanted. I know it is a small part of a small audience.
If I can find the samples I might even try encoding them

[ChrisB]

Not sure Tricky - as you say vanishingly small audience there. Sampled sound is something I've not gone near on the beeb before so it's all new. I'm sure I read somewhere that the samples in the game are a colleague of the original programmer. I wonder if a "better" source might be available.

Anyhow - on to today's release. This adds the following:

• Limited sound effects.
• Corrected a bug where number of men removed was not correct for failed capture.
• Adjusted the Marshmallow man appearance frequency to reduce it slightly.
• Added dance when ghost captured.
• Made the ghost a bit more invisible when not using the image intensifier (and more visible when the trap fires).
• Added logic for laser confinement system. Adds 10 empty traps - but will display as 9 as maximum.
• Went through code and removed several unnecessary CLC instructions for a bit more space.

I am hoping that this is now very close to final balance so any feedback is appreciated.

gb.ssd

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The question now is what to do with the remaining 75 bytes of space. Options are a larger marshmallow man, or - and I'm more inclined this way - to add some sort of limited animation for the ghost vacuum. Or there's always the small amount of corruption that I seem to have at the start of the scroll message - or do I try and stop some of the flicker on the drive screen... I also note that I haven't seen the amount corruption again - although I haven't specifically corrected this.

[ChrisB]

This one sucks!

I found a bit more space so here's a new version with the following changes:

• Added animation to suck ghosts to vacuum
• Cleared start of scroll to remove junk data that is sometimes visible
• Added another capture ghost movement frame
• Corrected an issue where the timeout animation might play at the end of a capture even if the capture was successful

A larger marshmallowman didn't make it (just a bit too big). This version has less than 10 bytes free of the areas that I'm using. If there is a significant issue discovered then the other capture ghost movement frame will be removed.

I feel this is probably as far as I think it's reasonable to go on the unexpanded BBC B - Please give this one a try - comments and feedback welcome.

gb.ssd

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[Cybershark]

This seems to hanging together very well now!

Wasn't there a plan to have the cars be able to speed up and down? I guess I probably misunderstood at the time. Not like it'd add anything to gameplay.

Can the vacuum sound effect be made to not interrupt the tune? No biggie, if not

There seems to be no check on whether some items have been purchased or not - it's only the traps that you should be able to buy multiples of, right? I seemed to be able to rack up several marshmallow sensors and image intensifiers, for example.

Sometimes I was seeing a weird green splat on the capture screen, but the screen would then exit before I was able to grab it.
Occasionally I see this sort of 'ghost trail' on that screen too:

More scarily, I once had the game completely lock up (while vacuuming) on the driving section:

[ChrisB]

Thanks for trying it out.

Cars and speeds - The different cars drive at different speeds so you get to the ghosts faster (and get a larger bonus for catching them) - they do speed up and slow down at the start/end - but that's just cosmetic.

Vacuum - The tune uses all three channels so the sound effects pause it whilst they are playing. I could possibly keep track of where it should be in the tune so it doesn't sound so disjoint.

Multiple purchases. Bother - looks like some logic missing here. This is why you give to other people to play Time to reclaim that ghost sprite space....

Green splat - Probably an artefact of failing to unplot the right sprite - will not be a problem if I reclaim the sprite space. I thought I'd sorted this out so I will have work out what's wrong for the SWRAM version.

Lock up - looks like the ghost hasn't moved to the "Right" place and wondered off screen. Going to have to vacuum lots of ghosts. You don't happen to remember where the ghost was in relation to your car do you?

Lastly - how do you feel it played? To me it seems a bit easy - but then again when you know what you're doing on the C64 version that also seems quite easy to beat.

[Dave_E]

I had a play of the new version last night. I really like the 'hoover' effect of the ghost on the car screens.

Having criticized the ghost catching on the 'building' screens in a previous post, I think you're right when you say in this new version, catching the ghosts now almost seems "too" easy - the circling motion sometimes means they just sort of hover over the trap right in its "line of fire". I found that in this new version, I didn't really even need to push the two ghostbusters together 80% of the time. I lost the whole "trapping the ghost" feel of the SNES and Speccy versions; I just waited until the circling ghost was a few pixels from where I predicted the trap would "get him" and tapped the fire key twice - and it almost always worked. That doesn't really seem to be what we want, I'd imagine. The previous version felt more like what we want, it was just the ghost escaping over the top of the beams and the 'having to press the fire key a few times' bug that brought that one down a bit.

I think it's a difficult one to call - having just replayed the Speccy version, you can also use the same strategy occasionally to get the ghost (i.e. abandon trying to trap him between the beams and just tap Fire twice and hope for the best). It's more my observations than anything that needs fixing...

To me it plays almost identically to the versions I know and love now. Just doesn't have the scrolling lyrics on the opening screen yet.

[ChrisB]

Thanks for the comments Dave. It is my intention to do the lyrics - but they are right at the end of the priority list.

As you may have noticed currently the ghost circles (it actually octagons) in different directions for each capture screen. I've changed this so the direction change happens periodically during capture screen instead of at the start - which adds randomness. I've added to this a comparison with the PK energy level so that the routine uses the PK level to determine how frequently to change direction. At low energy levels the direction change is rare - but towards the mid/end of the game this will happen a lot more frequently making the ghosts harder to catch as the game progresses. Please let me know what you think.

Also fixed is the ability to buy lots of the same thing and I've made the tune keep time when it's interrupted. Does this sound better? Lastly the scond ghost sprite has been removed so the corruption should also have been corrected.

I have had trouble recreating the total lockup despite catching many ghosts. If it happens again please let me know.

gb.ssd

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[Cybershark]

Also fixed is the ability to buy lots of the same thing and I've made the tune keep time when it's interrupted. Does this sound better? Lastly the scond ghost sprite has been removed so the corruption should also have been corrected.

I have had trouble recreating the total lockup despite catching many ghosts. If it happens again please let me know.

Aside from me being crap at catching ghosts that was much smoother! Music/vacuum suits better and no green splodges

Didn't encounter any problems for ages, until I was dragged away from one building scenario - I'd dropped my trap, went to position the first man and it just took me back to the street map? There I noticed a building gone white (rather than purple or red) and when I started my drive to it, I got the crash again, just after I used my vac

[ChrisB]

What emulator version and configuration are you using? The symptoms sound like the area used to maintain the status of each building (36 bytes in page 9) is being overwritten. Can't seem to get it to happen here.

[Cybershark]

What emulator version and configuration are you using?

Sorry, should've stated!

I'm running the latest version (v4.19) of BeebEm in plain ol' Model B mode.

[fwibbler]

I've had a few plays of this now and these are my thoughts / findings...
On the ghost catching screen if you fail to catch the ghost then the 'he slimed me' substitute sound effect is played before the ghost touches the man.
Also, 3 times now the ghost has escaped by going through the top of the left beam. Slightly annoying, but its not as blatent as it was before.

Also on the ghost catching screen, I find the ghosts are very easy to see. No point to the image intensifier for me.
On the Spectrum version, they flicker and disappear every now and then...
But this is not a major problem.

Overall, I'd say the difficulty is about right.
I find the game plays quite well (probably better than the Spectrum version I grew up with (just had a quick go, yes it does!)).
This is another welcome conversion for the Beeb. Thanks very much for your time and effort. Much appreciated.

Side note, I'd love to know who programmed the Spectrum version of this and how much time and resources they were given to do it etc...

[ChrisB]

Thanks for playing fwibbler.

Going through the beam - I'll need to look into that. As an aside the beams are probably a bit long (certainly longer than the other versions) so there might need to be some minor tweaks there.

Ghosts being easy to see. Yes - they are. But then they are on the c64 version which seems to use some sort of palette trick to mask them. I had a look at the spectrum and see what you mean. It might be a sprite/colour clash restriction that made them go down that route. Here's a couple of C64 ghost with no image intensifier - you can see that some of the colours are missing but it's otherwise quite easy to see. I can remove more colours but it does depend on the screen that you have. Some of the brick colours have large areas of colour that make the ghost invisible.

c64 obscured.png (3.77 KiB) Viewed 877 times

However - the more important question is did you see the crash that Cybershark saw?

[fwibbler]

Yes, I see what you mean with different buildings giving different levels of invisibility.
I haven't managed to get it to crash yet. I'll keep trying

[ChrisB]

Still not able to make it crash here.

Attached is another version. I have reset the stack pointer to give some more space (some city data is stored in page 1 so there might have been some interference there - although I see significant space in my emulators.) - But this is just a guess at this stage. I've also corrected some interrupt handling to allow the Master to work.

I've also further reduced ghost visibility when you don't have the image intensifier. The ghost will now only be visible over black pixels. Thoughts welcome.

gb.ssd

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Lastly the colour of the roads has always been something that I was unsure about. Here's a version of the map with blue roads. This would mean that I'd need to change the "ghost coming" colour to - probably - cyan (along with the ghost bait). To me it looks "cleaner" and corresponds with the blue roads in the driving section. Again - what are people's thoughts.

[TobyLobster]

I thought the text could benefit from some pixel tweaking, like this:

[ChrisB]

The more I've looked at them the more the blue roads have grown on me. A such here's a version with blue roads and TobyLobster's tweaked road names.
Interestingly these compress sightly better than the previous ones. Opinions anyone?

gb.ssd

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Still not made it crash...

[fwibbler]

Personally, I preferred the dithered roads, but I won't throw a tantrum if you stick with the blue ones.

Also, just noticed that the Spectrum version uses the same building graphic for the 'slipping past the Marshmallow man scene', that it does for the GHQ.
I assume that was to save space. Would it help to do that for the standard Beeb version too?

Also, what sort of things do you have in mind for the enhanced version? Should we all be building up a list?

[ChrisB]

Reference blue - I'll see what the consensus is. My preference is blue as it makes the edges of the other sprites "cleaner". Wonder if this could be an option - there's not much code difference.

Yes - I've reused a building for the marshmallow - the CPC does this as well. The building are made up of "tiles" so the GBHQ is a variant on the large arch building.

Enhanced version is intended to include (in no particular order):

• A custom "sneak" screen background.
• Larger Marshmallow Man (the sneak screen may be slightly different as a result)
• Animation for leaving GBHQ.
• Ghostbusters car parked outside the buildings.
• Sampled sound.
• A finale screen possibly with minor gameplay.
• Keymaster and gatekeeper wondering round the map and causing zuul to arrival.
• Any other animations I can get added.
• NULA support

Anything I've missed?

[fizgog]

I prefer the blue road looks better than the dithered gray, you could always make it proper gray in the NuLA version

[ChrisB]

Time to go sideways.

This version adds sideways ram support which brings back lots of the removed functionality. The SWRAM bank in use is displayed with the initial instructions (or X if none detected). Other changes for the SWRAM version include

• Animation of ghostbusters leaving GBHQ
• Larger Marshmallow man - Note that the end screen is probably broken and not able to be finished - will be replaced.
• Ghostbusters Car is present at the capture and GBHQ screens

gb.ssd

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[fwibbler]

Hi,
I've had a brief play of this although I didn't make enough money to go to Zuul

In other versions, the PK energy detector makes a building turn pink if a ghost is imminent. This version seems to go white (which is the colour it /should/ go when a marshmellow attack is due)...
Also, does the road scroll smoothly on real hardware? I'm using Beebem 4.17 and its not quite as smooth like the C64. (not a major issue, I mean, its not terribly bad)

Do you want more suggestions for enhancements (that aren't in other versions)?
Cheers!

[ChrisB]

Yes the colour is a palette restriction. One of the 8 colours is reserved to make the buildings flash red/green. I had magenta as one of the colours but that's been replaced with blue so it's no longer available. I chose white as most contrasting (with Cyan for the Marshmallow man - which hardly ever gets seen) - but could easily change it to one of the other colours.

Speaking of the marshmallow man he could be bigger still - there's no realistic memory limit now (samples permitting). At the moment he's made up of two body sprites that are 16 pixels wide (they overlap so his actual width is only 24 pixels) and a head that's 16 pixels wide. Obviously the larger he is the slower to plot in the finale.

The road has the 8 byte limit for scrolling left/right (which is 2 pixels in Mode 2). I think the C64 can scroll 1 pixel easily so it's smoother. The lines need to be completely replotted when you move left or right so that they stay in the same place - which leads to a bit of flicker on the ghost.

What enhancements are we talking about here exactly?

[tricky]

You could use the hsync trick for a single mode 2 pixel, but it moves the edges of the screen without lots of CPU cycles, but maybe it could be an option in the swram version. Should be ok if you are concentrating on the middle. My PacLand demo does this, but makes the screen wide enough to hide the edges My Rally-x demo does the work to tidy the edges, as does my r-type a-like.

Another option with the swram version is to have read only data in swram so that it could go on a rom for people without swram. This is how I try to organise mine, asking with putting the game in a rom compatible exe, costs a few hundred byes, but that is before the payload is decompressed.

[Cybershark]

Just had a couple of runs on the new version - on BeebEm again, but in Master 128 mode this time (to see the new features).

Sorry to say that I hit a road crash again both times! Captured about 8 ghosts (and had one escapee) on my first run, which ended thusly:

Second time around I got a bit further - PKE was up to around 8k, I think - and then this:

Is anyone else playing via BeebEm, or is it just me?

Also, a couple of times I've had my men in position (with their trap laid down) and been dragged away from the scenario. Is this something I ought to be concerned about, or should I just RTFM? Does seem to coincide with a red alert going off at a new building...

[ChrisB]

Is anyone else playing via BeebEm, or is it just me?

I use BeebEm all the time during development so I don't understand what is happening here. (I had corrected a couple of things that I thought might have caused it - but it seems no luck.). Is anyone else seeing this problem?

Meanwhile I've started on the new finale section with the larger marshmallow man.

[ChrisB]

Testing the finale.

Attached is a testing version that goes straight to the finale after the shop. Both with and without SWRAM versions are supported. For the SWRAM version on winning the screen will then scroll up to the top of the building and show the temple - there's no final animation as yet.

For the non SWRAM version you need to sneak in to the right of the marshmallow man. For the SWRAM version you need to go through his legs in the middle of the doors. Please let me know what you think.

Additional money is automatically added and the text appearance has been sped up for testing purposes.

gb.ssd

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[RobC]

Looks really good Chris - I particularly like the scrolling on the SWRAM version

I don't know if this is a bug, and I've not been able to recreate it, but I think one time the third Ghostbuster seemed to go straight to the door after the first two had gone through.

[ChrisB]

Here's an updates version with the final scene finished.

I've centred and tweaked the finale screen and added a (very small) piece of gameplay where you need to cross the streams to win. There's no time limit here so it is just a matter of moving the men towards each other - but at least you get to do it.

gb.ssd

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If there are no further comments I'll move onto the keymaster and gatekeeper on the map screen next.