[WIP] Moon Patrol conversion

[DanyPPC]

Good job !

ECS WHDLoad version works on WinUAE A600 configuration.

I also tested successfully the ADF version in A500 (512+512) / A600 (1MB) and A1200 (2MB) configs.

Only on WinUAE highspec AGA config the ECS version shows the gfx bug.

Thank You very much Jotd for this other great arcade port.

Those who criticize and know nothing about programming (and have never contributed to the Amiga scene) do not deserve your attention and all those homebrew developers who still dedicate time to the Amiga today.
Developers today should only be praised and encouraged !

[Neil79]

Originally Posted by jotd

BTW I'm infuriated by the comments of some bozos on indieretronews, they "counted the colors" and there are 8 colors on screen so a C64 could do a perfect port, and why isn't that dual playfield ECS perfect 50fps, blah blah. Yeah, right. Then count again, and at different stages of the game. Because during the black fade out of Turrican AGA or Banshee, there is only 1 color: black.

It's a difficult one and this isn't the first time a dev has been annoyed by the comments on our website.

What do we do?

Delete any negative comments and only allow positive ones?

- Our readers get annoyed that their posts are being removed and is seen as favoritism

Allow negative and positive comments

- Devs get annoyed at the negative and ignore the positives

Don't forget IndieRetroNews is a global site with thousands of views per day, and yes I do delete comments if they turn into nasty ones. You should see the amount of posts I get like this

" SCORPIONENGINE F**** THIS WEBSITE, SCORPION SUCKS "

Even had one guy try to take the site down because we featured a ukranian developer's game for the C64!

JOTD things will improve massively once the games out, as people on all requirements can play. Especially now you've released an ECS build too

PM!

[Neil79]

Originally Posted by DanyPPC

Those who criticize and know nothing about programming (and have never contributed to the Amiga scene) do not deserve your attention and all those homebrew developers who still dedicate time to the Amiga today.
Developers today should only be praised and encouraged !

There's been such posts on EAB in the past! Some people don't even like Arcade to Amiga ports

[Seiya]

Originally Posted by DanyPPC

Good job !

Only on WinUAE highspec AGA config the ECS version shows the gfx bug.

i resolved using previews whdload version. i put the game in Gamebase front-end and it uses a predifined script that use aga chipset.

[VincentGR]

As long they don't insult anyone, you can't delete them.
Ok they are bitter, but there is also freedom of speech.
Devs must just ignore them.
Even if it is a bad game (which jotd's aren't) you can't say anything nasty as someone's gives you a free game with what he knows.
People must be polite and thankful.

[Neil79]

Originally Posted by VincentGR

As long they don't insult anyone, you can't delete them.
Ok they are bitter, but there is also freedom of speech.
Devs must just ignore them.
Even if it is a bad game (which jotd's aren't) you can't say anything nasty as someone's gives you a free game with what he knows.
People must be polite and thankful.

Case and point..

Positive :

"Looks arcade perfect, but do we need AGA to do an arcade perfect port of Moon Patrol?"

Negative :

"Definitely not..even a C64 can probably do arcade perfect Moon Patrol. I think its either because of the Scorpion Engine contstraints or the Coder is just basically starting out and has not learned how to fully squeeze out the power of a 512kb or 1mb OCS Amiga's capabilities".

Negative :

"1MB ECS is too much. There are 8 colors on the screenshot. With some tricks a good coder could do that with dual play field 2 bitplanes. Compare this game to Agony, count colors and parallax scrolling. Only needs OCS+512kb"

Positive :

"This is done by a very competent developer who has already made numerous more or less pixel perfect arcade ports on the Amiga. It's made in assembler and he knows his stuff. He already tried dual playfield and it didn't work, as it messed up the timing of the underlying gameplay engine (which is 1:1 with the arcade btw)"

Positive :

"Wonderfull!"

A positive one from Jan

"calkster9 January 2024 at 15:13
omg! I have been wanting this for years and just last Sat. I was begging for it on the "Pintz and Amiga" Twitch stream and here it is. Here take my money, donations, etc.?"

See what I mean? Positives get ignored

[Neil79]

Anyway, new article to reflect latest beta!
https://www.indieretronews.com/2024/...sic-as_29.html

I can't really say anymore positives than I have already

Unknown commented on "Moon Patrol 500 - 1980's Arcade classic as an Amiga conversion by JOTD gets a new OCS , ECS, and enhanced AGA beta build!"
4 mins ago
Great work ! One of my favourite arcade of eightees is now playable on any Amiga.
Thanks and don't forget to donate to support all Amiga developers.

[jotd]

thanks for your support. I've very glad about the coverage of the game on indie, and I'm not saying that we should delete negative comments. I was just ranting here about how ignorant some people can be (and it shows when someone says that it's because of Scorpion Engine...) and those are probably one that don't even know anything about coding.

They heard that amiga can do 256 colors so why not all games have 256 colors?
They saw a demo with 235346 objects moving so why not all games can do the same?
Etc, etc why isn't it running on ZX81, etc. etc.

I love constructive advice like DonAdan, mcgeezer, ross and others can provide to improve whatever needs to be improved.

It's also perfectly annoying not to be able to deliver a 1982 game 1:1 on ECS. Some games use some specific hardware (like irem m52 hardware) which makes things more "interesting". Game can also move 48 sprites in real time and 3 scrollable layers + tileset. A beast even if the graphics don't look much. If some are interested I can explain the technical aspects of the port, which is greatly different on ECS & AGA. Pretty sure Scorpion Engine can't do that (yet).

[Neil79]

Originally Posted by jotd

thanks for your support. I've very glad about the coverage of the game on indie, and I'm not saying that we should delete negative comments. I was just ranting here about how ignorant some people can be (and it shows when someone says that it's because of Scorpion Engine...) and those are probably one that don't even know anything about coding.
.

Thanks dude

Just waiting on Saberman for a new video!

[jotd]

Originally Posted by Seiya

i resolved using previews whdload version. i put the game in Gamebase front-end and it uses a predifined script that use aga chipset.

for that particular game & whdload it's a bit complex

- if you have an AGA computer you can run the ECS slave version and it will be okay, but I recommend of course the AGA version
- If you have an ECS or OCS computer and fastmem, use the ECS slave which works on OCS
- If you have 1MB OCS you're stuck with the poor OCS version

When running from floppy, I've created a small startup shell which selects the best version (well, once the ECS version will be fixed, thanks for reporting)

[VladR]

Originally Posted by jotd

It's also perfectly annoying not to be able to deliver a 1982 game 1:1 on ECS.

I understand it feels annoying, but it's also unreasonable expectation.

Arcade Manufacturers kept "glueing" many various CPUs onto the main board as they saw fit.

Some boards had multiple DSPs, multiple Z80s, multiple 68000s and/or 6502s. Amiga has, what - a grand total of ONE 68000 ?

The moment you can offload some component of your engine to a separate CPU and not worry about it anymore, things get much easier (from a coder's perspective).

I don't recall from the top of my head what was the exact CPU/RAM breakdown of this particular arcade board.

[Rob68K]

Crabs in a bucket.
Those who perhaps even have the knowledge to do the job will critiscise those who are actually doing it precisely because of the fact that they do not have what it takes to apply their knowledge to make a completed product.
They're just bitter because you're forcing them to confront their shortcomings.
Many armchair quarterbacks in this scene.
Very few with the determination to complete a project.
Their criticism should just be considered as white noise.

[VladR]

Originally Posted by Rob68K

Their criticism should just be considered as white noise.

/FACEPALM
You have completely misunderstood what I said if you took it as a criticism.

There was absolutely no criticism of jotd's work in any way shape or form. I was actually flattering him (but you didn't notice it at all, obviously)


But, to put it explicitly bluntly - YES, it is an achievement to pull off Moon Patrol on 68000, considering the original arcade board has like 4-5 chips.

[jotd]

I don't recall from the top of my head what was the exact CPU/RAM breakdown of this particular arcade board.

the CPU is a simple Z80 but the graphics capabilities are very good, with 2 independent layers (able to display only fixed graphics) and 1 scrollable tile layer on the bottom third of the screen (to scroll the ground). Plus 64 16x16 sprites but the game only displays 48

That alone is a great challenge for our beloved machine, as we'd need 3 or 4 independent playfields to do the same as the original game.

VladR: I don't think that Rob68k reply was aimed at your reply. No offense taken by my side from any message of this thread or forum BTW.

[VladR]

Originally Posted by jotd

the CPU is a simple Z80 but the graphics capabilities are very good, with 2 independent layers (able to display only fixed graphics) and 1 scrollable tile layer on the bottom third of the screen (to scroll the ground). Plus 64 16x16 sprites but the game only displays 48

That alone is a great challenge for our beloved machine, as we'd need 3 or 4 independent playfields to do the same as the original game.

I understand the technical challenges when porting a game from a completely different architecture. The Bandwidth, multiple buses, multiple specialized chips - it all needs a raw CPU power to replicate (or very clever coding and workarounds to make it work with the architecture of the Amiga (or its different chips) - which is exactly what you're doing here - though I wonder exactly how many people understand that fact).

For me, personally, this thread is very inspirational and I am grateful for your work

[Don_Adan]

On latest zzbylu video.

[ Show youtube player ]

Minimum 2 graphics bugs.
"You have a record" text still dont displayed correctly after first etap.
And blue point visible, after second etap. "Sorry no bonus"

[jotd]

okay, you didn't ask for it but here it is: technical breakdown

ECS version:

It uses a 16-color single playfield version. Some colorblind clowns stated that there are only 8 colors on that game, but actually even 8+8 colors (for ECS dual playfield) can't be done. Actually, even 16 colors is difficult, as tiles, bobs, and backgrounds have independent palettes.

so the top panel has its colormap (which is the tiles palette), which is changed by our beloved copper right afterwards to set BOB colors.

From that point, if you write something, then the colors will be wrong (which is why that BOB colors are reset when completing a section, to revert back to tiles colors), but fortunately not a lot of text is written to the screen below top panel when sprites / mountains are shown.

The blue layer mountain is drawn with blitter to simulate scrolling. It uses just 3 colors (black and 2 blues) so with clever palette layout, only 2 bitplanes need to be blitted.
And when the color becomes all blue, instead of blitting a big blue rectangle (which would cost too much), the background color is changed to this blue color.

The green layer mountain is drawn the same way, but using a mask not to overwrite the blue mountain below. When the color becomes all green, background color is changed to green. Those dynamic changes don't happen at the same position all the time: the mountains can change their Y start too depending on the scenery. 3 bitplanes are required. This costs a lot of blitter time.

The ground strip is drawn the same way, except that I choose to keep only 1 bitplane. The color is also changed dynamically to orange (which is a color that isn't in the BOBs palette).

Then the BOBs are drawn, sometimes reusing some blue mountain colors for ground objects like rocks as else there wouldn't be enough colors, even with 16 colors.

To save more colors, some objects like the explosions are hardware sprites. Ships are also hardware sprites, except when there are 9 of them (grrrrrr) or when the ship is falling on the player, in which case a BOB is displayed instead.

Sprite multiplexing between top & bottom is active, which allows to display 16 hardware sprites at the same time. 2 explosions + 8 chips for instance. Some sprite grouping is done too to convert 2 vertically aligned sprites into one 16x32 sprite.

There is one color missing for base of the space plant, but since it's very low, it can be changed dynamically by the copper when reaching the ground. Top of the space plant is 2 sprites, which saves one or 2 precious color entries. Since there can't be more than 3 space plants at the same time and the ships aren't there to bomb the scenery at this point, it works, we have enough HW sprites.

Aaand that's it for ECS

Now for AGA:

Game uses 16+16 color dual playfield. Top panel is done the same way but things get different from there.

Blue mountains are displayed using different bitplanes, on one playfield dynamically Y-adjusted depending on the current mountain Y start.
Green mountains are blitted on the other playfield. No need for mask this time. More colors & no mask mean that we can reinstate moon city background which was left behind in ECS.

Same background color tricks as ECS.

Now the scrollable ground part reuses the blue mountain playfield, but they are far enough Y wise not to conflict. So a different scroll & shift value can be applied, which makes 2 hardware scrolling strips at different speeds, and allows to scroll all 4 bitplanes without blitting, which reinstates the moon base & more colors for craters & scrolling letters.

Another trick is used for vertical shot: this isn't a sprite or a BOB but a TILE... (yes). I could have used a sprite but there are 4 of them at the same time so it would have eaten all the slots, plus multiplexing splits sprites top/bottom so it wouldn't work. Instead, since only 1 color is used, and the background mountains only use 3 planes, I've carefully selected a bright color for color 8, and only draw on 4th plane. A trick that worked well with the shots in Galaxian. Here you can see color changing when passing on the mountains, but very simple to handle otherwise, and does the job.

Simulating 55/56Hz was another thing which wasn't so trivial. I usually check a counter and if it reaches a given count, update the logic twice instead of once. It works for most games, but here it causes a lot of problems. Using another source of interrupt (software, CIA) also crashes for an unknown reason, BUT something works: I call the copper interrupt in the middle of the screen too, just after a software interrupt request (software interrupt is masked so no software interrupt occurs). When the copper interrupt is handled, it checks that software interrupt is set, and if it's the case, it's because it's mid-screen, so after 10 times, calls IRQ, else does nothing. And bottom of screen copper interrupt happens, like before, giving the extra speed without brutal increase of the game counters, so game behaves properly, and gets the expected 10% speed increase.

A final word about sound: no9 did a great job as always shoehorning the whole tune into ONE bloody channel. Which leaves 3 slots for SFX. OCS/ECS/AGA versions have different sampling frequencies for SFX so OCS version fits in 512k chip/512k fast. Sorry for purists who wanted AY-8910 emulation to fit in 512k with 8 colors.

BOBs & sprites are the same as ECS. Less color tricks are required because we have more colors available (blue mountains don't get in the way).

[Rob68K]

Originally Posted by VladR

/FACEPALM
You have completely misunderstood what I said if you took it as a criticism.

There was absolutely no criticism of jotd's work in any way shape or form. I was actually flattering him (but you didn't notice it at all, obviously)


But, to put it explicitly bluntly - YES, it is an achievement to pull off Moon Patrol on 68000, considering the original arcade board has like 4-5 chips.

I don't know why you presumed I was talking about you.

[TjLaZer]

My lowly NTSC Amiga 1000 with 512k Chip and 1MB Fast is happy that she can play this game! Excellent update!

[jotd]

great!

BTW ECS version issue fixed. Will publish an update soon.