Ghostbusters - Development Diary

[TheMole]

1 minute ago, OLD CS1 said:

Just played a quick game.  A couple of things I noticed:

• I believe in the C64 version, you can drop your trap higher or lower on the screen (@wongojack can you confirm?)
  • In the C64 version you can, and I tried to add that as well, but I couldn't get the transition from sprite to pattern to look reasonable so I abandoned that idea 😕.
• The instructions note the trap moves slower coming down than going up.  It moves the same speed up and down on the TI.
  • I didn't know that! That should be easy to add as well!
• I sussed out when to use the bait.  Having to hit B is difficult when playing with the joystick and sitting back from the console.  However, I only got three uses of it.  Perhaps some logic to only allow a single drop at a time is in order.
  • Currently, the game ignores 'B' presses for 1 second after the first time the button is pressed. Of course, if you (like me) have a tendency to mash the B button over and over again, it might drop multiple bits of bait...

 

[cbmeeks]

7 hours ago, wongojack said:

Apple II

 

Amstrad CPC -

 

 

MSX -

Funny, but to me the Apple II version looks the best.  I love the A2 but it's rare when you can say the graphics are better.  lol

 

[+wongojack]

1 hour ago, cbmeeks said:

Funny, but to me the Apple II version looks the best.  I love the A2 but it's rare when you can say the graphics are better.  lol

 

LOL - I really like the A2 version.  I think that is the best screenshot of the game (although the car looks pretty good).  It's mostly the limited colors and at times the color clash that take it down a bit.  Also, the almost complete lack of sound means you aren't distracted by anything and have time to scrutinize the details more.

[+wongojack]

8 hours ago, TheMole said:

I wasn't aware there were versions that brought you to Zuul before the PK level hits 9999. They might be doing that to avoid players winning the game by only catching marshmallow men (if you only buy a cheap car, the bait and a single trap, you can easily win the game by just catching marshmallow men and never going to a building).

I suspected the same.  This is a strategy I have considered but never tried to execute.  When playing the 2600 version, I was trying to determine how I could reach 1 million points the fastest, and this is exactly the type of gameplay that could do it.  Still have yet to try it . . .

I like that the game will stop the player from playing this way btw.  In fact, I'd prefer more Marshmallow Attacks, so you had to play the opposite way - stay hunting ghosts to try and avoid him or he gets you (maybe even a 6th time).

Also, consider a situation where his appearance is triggered but the PKE level reaches max value at the same time.  So, his trigger value is 9800, but the level jumps all the way from 9600 to 9999.  This could happen if the player misses a ghost (either on the map or on the ghost catching screen), and some ghosts arrive at Zuul at the same time.  I assume that his appearance would not occur, and the player would instead go to Zuul.  This sorta happened on the MSX version.  He triggered, and I stopped him and then I got notified that Key and Gate had entered Zuul (but it was before the meter reached 9999).

[+wongojack]

8 hours ago, OLD CS1 said:

Just played a quick game.  A couple of things I noticed:

• I believe in the C64 version, you can drop your trap higher or lower on the screen (@wongojack can you confirm?)
• The instructions note the trap moves slower coming down than going up.  It moves the same speed up and down on the TI.
• I sussed out when to use the bait.  Having to hit B is difficult when playing with the joystick and sitting back from the console.  However, I only got three uses of it.  Perhaps some logic to only allow a single drop at a time is in order.

I have been saving playing the C64 version for the end of my tour, but I will try this weekend.

 

I can confirm that some versions definitely let you move both horizontally AND vertically (X/Y) on the sidewalk before dropping the trap - BUT does the trap actually land in different positions along the Y axis?  It might just plop it in the middle no matter where you stand.

[+OLD CS1]

14 minutes ago, wongojack said:

I can confirm that some versions definitely let you move both horizontally AND vertically (X/Y) on the sidewalk before dropping the trap - BUT does the trap actually land in different positions along the Y axis?  It might just plop it in the middle no matter where you stand.

ISTR in a strategy guide that putting the trap higher helps with the higher-floating ghosts.  Given the difficulties @TheMole had with sprite-tile transition, and how the game plays over-all, I do not see this as a huge issue for us.

[TheMole]

Here's a new version which changes the following:

• Trap moves slower going down than going up. I'm not sure what the gameplay implications of this are, to be honest, but since some strategy guides seem to point this out I figured it couldn't hurt to add 
• I now play a BLIP sound whenever you drop bait, to hopefully make it clearer that the bait has been dropped and avoid super-anxious button mashing.
• Increased the time-out for dropping bait to two seconds, so even button mashers won't needlessly waist precious bait.
• If you're out of bait though (or never bought any to begin with), pressing 'B' will make a BRRR sound and will scroll a message in the status bar
• I tweaked the number of marshmallow encounters a bit, it should now be much less likely that you will encounter as many as 5

I'm thinking about what I can do to void the "win without catching any ghosts" strategy, but I don't like the idea of bringing the player to ZUUL sooner. That just feels broken to me. Perhaps I should skip the first two or three marshmallow man encounters if the number of ghost catching attempts is lower than a certain threshold value at the time the encounters are supposed to happen?

gbust.rpk gbustc.bin gbustg.bin

Edited August 17 by TheMole
missing attachments

[+OLD CS1]

7 hours ago, TheMole said:

If you're out of bait though (or never bought any to begin with), pressing 'B' will make a BRRR sound and will scroll a message in the status bar

Cool!  Such a message exists in the original game: https://github.com/SingleCopy/C64-Ghostbusters/blob/main/Code/Screens/CityMapScreen/CityMapScreenData.asm

 

 

*= $3a78
TEXT_SORRY_NO_BAIT:
    .text "SORRY, NO BAIT. " + @"\$ff"

 

[+wongojack]

7 hours ago, TheMole said:

Here's a new version which changes the following:

• Trap moves slower going down than going up. I'm not sure what the gameplay implications of this are, to be honest, but since some strategy guides seem to point this out I figured it couldn't hurt to add 
• I now play a BLIP sound whenever you drop bait, to hopefully make it clearer that the bait has been dropped and avoid super-anxious button mashing.
• Increased the time-out for dropping bait to two seconds, so even button mashers won't needlessly waist precious bait.
• If you're out of bait though (or never bought any to begin with), pressing 'B' will make a BRRR sound and will scroll a message in the status bar
• I tweaked the number of marshmallow encounters a bit, it should now be much less likely that you will encounter as many as 5

I'm thinking about what I can do to void the "win without catching any ghosts" strategy, but I don't like the idea of bringing the player to ZUUL sooner. That just feels broken to me. Perhaps I should skip the first two or three marshmallow man encounters if the number of ghost catching attempts is lower than a certain threshold value at the time the encounters are supposed to happen?

gbust.rpk 79.64 kB · 3 downloads gbustc.bin 512 kB · 6 downloads gbustg.bin 8 kB · 4 downloads

These all sound like very interesting improvements, I will play more this weekend.

 

My instinct is to go the other way.  If the number of ghost catching attempts is lower than a certain threshold then make it so they will have too many Marshmallow attacks (lowering their score).  Or maybe if ghost catching attempts < N and Marshmallow Attack averted then increase PKE by 1000.  That is sorta the same as taking them to Zuul early, but only happens if the score is being deliberately manipulated.  Not claiming these are great ideas, just brainstorming a little.  I like this process.

 

By the way, for those of us uninitiated to the world of the TI99 what's the difference between all the files above?

[+OLD CS1]

36 minutes ago, wongojack said:

By the way, for those of us uninitiated to the world of the TI99 what's the difference between all the files above?

The RPK file is essentially all cartridge parts plus metadata for the cartridge and its parts for use with MAME.  The "c" and "g" files are ROM and GROM files, respectively, which are two parts of the same cartridge for loading on an FG99 or in Classic99.  @Tursi's Classic99 manual has a definitive breakdown on these file types.

[+wongojack]

19 minutes ago, OLD CS1 said:

The RPK file is essentially all cartridge parts plus metadata for the cartridge and its parts for use with MAME.  The "c" and "g" files are ROM and GROM files, respectively, which are two parts of the same cartridge for loading on an FG99 or in Classic99.  @Tursi's Classic99 manual has a definitive breakdown on these file types.

So RTFM?

 

How about this, does it matter which file I use in Classic 99?  Sounds like .rpk is not the way to go.

[+chue]

7 minutes ago, wongojack said:

How about this, does it matter which file I use in Classic 99?

You need both “c” and “g” in the same directory, but you should open the “g” file. 

[+mizapf]

14 minutes ago, wongojack said:

How about this, does it matter which file I use in Classic 99?  Sounds like .rpk is not the way to go.

RPK is the format used with MAME that contains all dump files of the cartridge in a single file, including an XML file that tells the emulator how to handle those dumps.

[+OLD CS1]

1 hour ago, wongojack said:

How about this, does it matter which file I use in Classic 99?  Sounds like .rpk is not the way to go.

Correct, not the RPK.

 

1 hour ago, chue said:

You need both “c” and “g” in the same directory,

Yes.

1 hour ago, chue said:

but you should open the “g” file.

This does not matter.  You can open any one of related files and Classic99 will "assemble" the cart from its individual parts and run them as a real TI does with a real cart.  In this specific case, the "c" file has a header which allows you to run the game without the "g" (GROM) part.  The GROM part is used here to add a special effect to the MTS and MSS.

Edited August 17 by OLD CS1
Corrected the bit about using c and g parts of Ghostbusters.

[+wongojack]

Whoa - now that's a response.  Thank You!

 

I want to add that I am totally a RTFM kinda guy.  I was trying to re-write a DOSBOX config file when I posted that comment.

[+chue]

15 minutes ago, OLD CS1 said:

This does not matter.

Good to know!

[+OLD CS1]

15 hours ago, TheMole said:

Perhaps I should skip the first two or three marshmallow man encounters if the number of ghost catching attempts is lower than a certain threshold value at the time the encounters are supposed to happen?

I can lean toward this.  You should not be rewarded if you are not going to actually play the game, and gaming the game is not playing.  Preventing Stay Puft from showing up a few times should ensure a player cannot amass more money than the original bank balance.  Anyone who gets pissy about that can shove it.  I mean, seriously, why play the game if you are not going to play it?

[+OLD CS1]

BTW, "mayer" is actually spelled "mayor"

[TheMole]

6 hours ago, OLD CS1 said:

BTW, "mayer" is actually spelled "mayor"

Whoops, must have been listening to John Mayer while I was coding...

I've fixed it on my machine, the next release should include the change, thanks!

[PeBo]

I don't pop by any forums much these days, so this is the first I've seen of this project.

Always up for a new homebrew port, but coming from TheMole makes it truly exciting.

Your Alex Kidd sir, is a thing of beauty. Thank you for the hours of frustrating entertainment (frustrating in a good way) that it has provided.

I expect no less here, so thank you in advance.

[TheMole]

16 hours ago, PeBo said:

I don't pop by any forums much these days, so this is the first I've seen of this project.

Always up for a new homebrew port, but coming from TheMole makes it truly exciting.

Your Alex Kidd sir, is a thing of beauty. Thank you for the hours of frustrating entertainment (frustrating in a good way) that it has provided.

I expect no less here, so thank you in advance.

Thanks, I appreciate the kind words! I'm actually still working on Alex Kidd and hope to release the full game soon-ish. I have 8 out of 14 levels finished and am working on adding boss battles and finishing the story.

[jrhodes]

2 hours ago, TheMole said:

Thanks, I appreciate the kind words! I'm actually still working on Alex Kidd and hope to release the full game soon-ish. I have 8 out of 14 levels finished and am working on adding boss battles and finishing the story.

Isn't that one f18a only?

[TheMole]

12 hours ago, jrhodes said:

Isn't that one f18a only?

Not at all, if you have an f18a you will see significant graphical improvements, but it works just fine on a stock system!

Edited August 23 by TheMole

[JasonACT]

I've found a glitch as you steer left and right while travelling...

 

 

This is a real NTSC TMS9918A, and the mode change for the status bar hasn't quite happened in time.  It's fairly repeatable, but hard to capture like I did here.  Emulators don't seem to show it at all...

 

The reason I bring it up is, @visrealm has fixed this in his Pico9918 project for me, and we now have the TMS and Pico doing very similar things, but it's not perfect on either device - I think the 5 sprite detection logic could do with an earlier scanline detect, extra fixed but small delay, and then switch modes to make it work more reliably.  The small delay I mention may need some testing to get right.

 

And I suspect the F18A may also have issues on that scanline, but I don't have one to test.

[TheMole]

3 hours ago, JasonACT said:

I've found a glitch as you steer left and right while travelling...

 

This is a real NTSC TMS9918A, and the mode change for the status bar hasn't quite happened in time.  It's fairly repeatable, but hard to capture like I did here.  Emulators don't seem to show it at all...

 

The reason I bring it up is, @visrealm has fixed this in his Pico9918 project for me, and we now have the TMS and Pico doing very similar things, but it's not perfect on either device - I think the 5 sprite detection logic could do with an earlier scanline detect, extra fixed but small delay, and then switch modes to make it work more reliably.  The small delay I mention may need some testing to get right.

 

And I suspect the F18A may also have issues on that scanline, but I don't have one to test.

 

That's weird, I tested on my NTSC tms9918 machine as well as my (previously PAL) f18a console, and both seem to switch at the correct time with the current settings. I can bring the five sprites up a scanline, but that will make the road markings dissapear even sooner (they dissapear a line or two before the actual switch already with the current setup). Could there be differences between machines in how quickly they apply the mode switch?

 

*edit* you can try the version below, it puts the 5 transparent sprites one scanline higher, let me know if that fixes things for you!

gbust.rpk gbustc.bin gbustg.bin

Edited August 23 by TheMole
Added test version with earlier scanline detection