NeoGeo Metal Slug conversion to Amiga 500 - madman task ;-)

[tomcat666]

Originally Posted by roondar

It's a great example of using a system well for sure. The 'interlacing' the whole game to get more colours trick is done very well too.

On YouTube it looks terrible, probably better on crt.... Great achievement nevertheless. In the end both 4mb STE users can now play the game

[Tigerskunk]

Originally Posted by x-vision

I can't believe there is already a great for port of Metal Slug for a simple Atari STE, and people here saying it needs AGA and 030

[ Show youtube player ]

Well, if there is one thing Metal Slug needs it's RAM, RAM and RAM.
And the STE can have 4mb of it, like Roondar said.

You could probably do something with lots of fast RAM and then copying new data to Chip when it's needed, but I would not want to code that.

[Rob68K]

Originally Posted by Tigerskunk

You could probably do something with lots of fast RAM and then copying new data to Chip when it's needed, but I would not want to code that.

True enough but no matter how quickly you could do that, it's still an overhead. I'm not familiar with the relative performance of the blitters but I would think that the Amiga's would have to be significantly quicker to make up for it. Particularly as the Atari's has a 0.86Mhz headstart?

The chipram caching of sprites isn't really that big a deal. I did something similar on the Megadrive and that's more fiddly.

[DanScott]

Originally Posted by Tigerskunk

You could probably do something with lots of fast RAM and then copying new data to Chip when it's needed, but I would not want to code that.

Probable easier than the "load off disk on demand" systems that were written for some games back in the day

[sandruzzo]

Come on! On Amiga we can do things very impossible! The real deal is the game coding itself, since it is a very big Project!

[roondar]

Originally Posted by Tigerskunk

Well, if there is one thing Metal Slug needs it's RAM, RAM and RAM.
And the STE can have 4mb of it, like Roondar said.

AFAIK, the STE can have 14MB of ST-RAM (i.e. GFX RAM) .

The game has just been optimised to use a lot less of it. Just think about it, 14MB of Chip RAM would be quite the thing. We very nearly got support for 8MB Chip RAM, but sadly Commodore ended up not implementing it in AGA.

Originally Posted by Rob68K

True enough but no matter how quickly you could do that, it's still an overhead. I'm not familiar with the relative performance of the blitters but I would think that the Amiga's would have to be significantly quicker to make up for it. Particularly as the Atari's has a 0.86Mhz headstart?

ST Blitter speed is dependend on how you use it. Apparently, if you use it properly and have BOBs that are 32 pixels wide or multiples thereof, you can get a throughput that is about the same (or even slightly higher in some cases) as the Amiga Blitter.

It's certainly faster than copying from Fast or Slow RAM using the CPU though.

Note: I am not an ST Blitter expert, I'm just repeating things I've seen on EAB and on YouTube - where talented STe coders have essentially 'tied' with the Amiga's Blitter speed for 16 colour low res screen modes.
Note 2: this speed comparison is valid for simple BOB blits. If you start using the tricks that Sandruzzo talked about, the result may be more in the Amiga's favour.

[Tigerskunk]

Originally Posted by DanScott

Probable easier than the "load off disk on demand" systems that were written for some games back in the day

True, but then, this I wouldn't even less want to code.

[sandruzzo]

this project should be "open source" so, more than one, could code, add gfx and sound

[Tigerskunk]

Not to be the party pooper here, but if we haven't managed to get this started over 47 pages, I see the chance of somebody taking this up and creating it on page 48 as extremely slim...

It's fun to talk about it as a theoretical subject, though.

[sandruzzo]

@Tigerskunk

It is very fun to talk about possible ways to do it! I won't be so impossible to do a "small" playable demo

[AnimaInCorpore]

Originally Posted by roondar

AFAIK, the STE can have 14MB of ST-RAM (i.e. GFX RAM) .

Well, using an emulator it's easy just to "activate" 16 MB of RAM (2 MB overlapped by the ROM) but on the hardware side 4 MB RAM is the maximum without any soldering/modifications (AFAIK).

Originally Posted by roondar

ST Blitter speed is dependend on how you use it. Apparently, if you use it properly and have BOBs that are 32 pixels wide or multiples thereof, you can get a throughput that is about the same (or even slightly higher in some cases) as the Amiga Blitter.

Actually the current approach hits a sweet spot on the Atari ST Blitter with 32 pixels wide sprites. Also line strips without any gaps are very effective.

Originally Posted by roondar

Note 2: this speed comparison is valid for simple BOB blits. If you start using the tricks that Sandruzzo talked about, the result may be more in the Amiga's favour.

In fact there's more to consider: having 4 MB "Chip-RAM" you can also store some DMA samples permanently. Also since the upper and lower screen borders can be removed as well the resolution can be increased from 320 x 200 to 320 x 272 without being a DMA cycle stealer. So even with some tricks the Amiga 500 cannot beat the Atari STE in this (very special) case.

[roondar]

Originally Posted by AnimaInCorpore

Well, using an emulator it's easy just to "activate" 16 MB of RAM (2 MB overlapped by the ROM) but on the hardware side 4 MB RAM is the maximum without any soldering/modifications (AFAIK).

Ah, I didn't know that. Still, 4MB is more than 2MB of the ECS/AGA machines. Also, I would honestly consider soldering/modding a machine to get to the higher numbers kind of 'cheating' when it comes to comparisons, but meh - it doesn't really matter I suppose.

Actually the current approach hits a sweet spot on the Atari ST Blitter with 32 pixels wide sprites. Also line strips without any gaps are very effective.

Ah, right. I thought it was multiples of 32 pixels, but in fact it's specifically 32 pixels wide objects. Good to know.

To be fair, line strips without gaps can probably be done quicker on Amiga Blitter as well than standard blits. Though it would be a pain to set up (blit both edges @ 4 DMA cycles per word, then the rest as a copy blit @2 DMA cycles per word).

In fact there's more to consider: having 4 MB "Chip-RAM" you can also store some DMA samples permanently. Also since the upper and lower screen borders can be removed as well the resolution can be increased from 320 x 200 to 320 x 272 without being a DMA cycle stealer. So even with some tricks the Amiga 500 cannot beat the Atari STE in this (very special) case.

I did not know you could have that high overscan without losing DMA cycles on the STe, nice.

As for DMA samples. It's an advantage, sure. But then again, streaming samples from Fast or Slow RAM in real time is not that much of an issue. Can be done for a quite low CPU overhead. GFX from Fast or Slow RAM is more complicated, for sure, as the data rate tends to be far higher.

[Rob68K]

Originally Posted by sandruzzo

this project should be "open source" so, more than one, could code, add gfx and sound

Good luck coordinating that.

[sandruzzo]

Originally Posted by Rob68K

Good luck coordinating that.

It's sounds likse a curse!

[saimon69]

Originally Posted by Tigerskunk

Not to be the party pooper here, but if we haven't managed to get this started over 47 pages, I see the chance of somebody taking this up and creating it on page 48 as extremely slim...

It's fun to talk about it as a theoretical subject, though.

Do i have to remember you the Rygar odissey? BTW if i was Sandruzzo (but am not) i would finish the OCS/ECS version too, even only with 32 colors ^^

[TCD]

Originally Posted by saimon69

Do i have to remember you the Rygar odissey?

Where is mcgeezer when you need him?

[sandruzzo]

Originally Posted by saimon69

Do i have to remember you the Rygar odissey? BTW if i was Sandruzzo (but am not) i would finish the OCS/ECS version too, even only with 32 colors ^^

I havent' forget it! But one simple small level, can be handled. Just to tell: You see? Amiga can do it...

[sandruzzo]

Originally Posted by TCD

Where is mcgeezer when you need him?

He is a great Man, and very talented coder!

[Rob68K]

Originally Posted by saimon69

Do i have to remember you the Rygar odissey? BTW if i was Sandruzzo (but am not) i would finish the OCS/ECS version too, even only with 32 colors ^^

Revealing intentions at any point before that at which it's virtually zero effort required to get it across the finish line is asking for trouble IMO.

From what I've seen of most projects that are in progress here, all premature exposure appears to accomplish is piling more pressure on the person who is undertaking the task, which is more often that not extremely unhelpful.

[Retro-Nerd]

Best is when ports come out of nowhere. Like the great Sonic Mastersystem to C64 port. Probably the best way to do it.