Jetpac for the Taito L System.

Sokurah

Sokurah

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Some of you may remember that I remade the C64 version of SQIJ for the Spectrum back in 2018 and then afterwards I then ported it to Taito's L System arcade hardware ... and ever since then I've wanted to make another game for that platform, but didn't really know what to do.

Two months ago I had an idea: I love JetPac ... and what would be more perfect than to port a pure arcade action game to an actual arcade platform, right?
:lol:
... so that's what I've done.

It's based on the reverse engineered source code I found online and then I've used that as the base, so this port has the same enemies, enemy movement, level progression, etc. as the original from Ultimate that we all love. I wouldn't say it was easy, but at least the arcade hardware uses a (slower than the Spectrum) Z80 processor, so that helped a lot
:mrgreen:


Gameplay-wise it's done, it only needs some music for the main menu and I also need to make some sound effects, and apart from cleaning up the mainmenu and perhaps a bit of polish here and there, it's done, so the release will happen in the near future.
... I should also have it tested on the real hardware before release to be sure it'll work on the real hardware.

This is how it looks now.

JetpacLSystemScreens.png
 
ExZX

ExZX

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Absolutely adore Jetpac. This was the first game I played on the Spectrum early 80s. My brother brought his friend's Speccy 48k home for a couple of nights and Jetpac was the game we played on a tiny portable B&W tele in the kitchen (the type with the dial for the channels so back when patience was key). Had to save up for a 48k Speccy of my own but Jetpac was the beginning
 
Sokurah

Sokurah

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96CR
qjuk said:
Nice!!!
I love Jetpac 😍
Interesting to see how this performs on an arcade board :cool:
Click to expand...
It performs quite well. The speed is not quite the same though. The Spectrum ran at 50Mhz (I think) and so does the arcade board, but that doesn't mean the Spectrum game runs at 50 FPS - maybe it was only 20FPS ... but it was very smooth and balanced.

But while the Spectrum game was highly optimized by some of the best coders on the Spectrum - for a Z80 running at 3.54Mhz, I think the arcade board only runs at 3Mhz. Much of the time it runs at full tilt, but sometimes - like with the second enemy, it slows down a bit - noticably, but not too serious ... just keep shooting them :D

The speed may have been more fluid if the game was coded from the ground up by me, but I've used someone elses framework/source, so I have to accept that I don't have 100% control of it ... but I'm happy with it anyway :geek:
 
Sokurah

Sokurah

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96CR
Sokurah said:
It performs quite well. The speed is not quite the same though. The Spectrum ran at 50Mhz (I think) and so does the arcade board, but that doesn't mean the Spectrum game runs at 50 FPS - maybe it was only 20FPS ... but it was very smooth and balanced.

But while the Spectrum game was highly optimized by some of the best coders on the Spectrum - for a Z80 running at 3.54Mhz, I think the arcade board only runs at 3Mhz. Much of the time it runs at full tilt, but sometimes - like with the second enemy, it slows down a bit - noticably, but not too serious ... just keep shooting them :D
Click to expand...
Just replying to myself here :geek: but the first link I found about the arcade board was not correct, so the 3Mhz I quoted for the Taito L System is wrong - it's really 6Mhz.

The slowdown I had sometimes is no longer relevant, because while I had disabled the "writing to the Spectrum screen-stuff" in the background, I had not disabled the part of the game that deletes (Spectrum) sprites again, so when that was removed too, I got a huge speed gain ... so now I'm working on slowing things down again :ROFLMAO:

Long story short: It's coming nicely along and is very close to being finished :coffee:
 
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