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

[idrougge]

One way forward would be to reimagine the game as a ZX Spectrum port. 256 x 192 resolution and monochrome should be easy enough on the RAM and DMA throughput.

[ross]

Originally Posted by idrougge

One way forward would be to reimagine the game as a ZX Spectrum port. 256 x 192 resolution and monochrome should be easy enough on the RAM and DMA throughput.

This made my day

[LongLifeA1200]

I think it provides the impetus to showcase how to navigate the limits of each Amiga system. It would make for a good tutorial. It's a game that is just out of reach so it forces you make decisions as to where to make modifications (read sacrifices). Clearly this thread is popular, so why stop?

[Master484]

One way forward would be to reimagine the game as a ZX Spectrum port. 256 x 192 resolution and monochrome should be easy enough on the RAM and DMA throughput.

Indeed, and on the AGA we could boost the monochrome visuals by giving it a smooth color gradient with the copper, putting an amazing 256 colors on screen, and thus making it a "real" AGA game.

And sprites could be used to make cool 4 color borders around the 256 x 192 game area.

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I think it provides the impetus to showcase how to navigate the limits of each Amiga system. It would make for a good tutorial. It's a game that is just out of reach so it forces you make decisions as to where to make modifications (read sacrifices). Clearly this thread is popular, so why stop?

That's right. "Big" arcade games like this are in the "border zone"; they are something that the Amiga can't easily replicate, but still they seem to be theoretically doable, if well designed and programmed.

But even a one level demo would take a lot of time and work, and this is why it's rare that someone would actually attempt these conversion projects.

Theoretically I have the skills to make this game with Blitz Basic, and I estimate that Blitz is fast enough to run it at 25 FPS (with some slowdowns / frame skip).

But it would be a lot of work, and I also have another project going on, so unfortunately right now I can't do more than the small GFX test that I posted. Maybe sometime in the future I could give it a try, but in all likelyhood it won't happen soon.

Putting some graphics to the screen is always easy, but making the actual game logic for a "real" one level demo would take many months.

The levels in Metal Slug are quite short and straightforward, but they are absolutely full of "events". Houses break, soldiers cook food, cars break, tanks fall from a cliff, boat sinks, mid boss comes through a wall, and so on.

This task would be all about programming of all those events, small animations, and enemy behaviours, and preparing the assets and putting everything to place, and this stuff would be very time consuming.

But maybe someone else is indeed crazy enough for this task?

[modrobert]

I'm trying hard not to disagree with anyone this time (famous last words).

Regarding developing the original Metal Slug for Neo Geo, to me it looks like drawing the graphics was where most of the time was spent when counting man hours (perhaps years?), imagine creating all those different animation steps by hand, each frame. Sure, the program (engine) to handle animations and move all the graphics around took effort as well, but not nearly as much, right? This is not the first side scrolling "bullet hell" title with an action hero running around so assuming some code could be used from previous projects. Earlier in this thread I read some posts arguing about having all the graphics was less than 1% of the work, I realize now perhaps they meant converting existing graphics for a port was less than %1 of the work? Still not sure...

This is based on my experience playing Metal Slug to the end in emulators, playing ports on the Playstation (PSX) and some later version (Metal Slug 4 or 5?) on the Xbox. I haven't actually played Metal Slug on real Neo Geo hardware. I do know some 68k assembler programming, assuming that's what they generally used on Neo Geo for Metal Slug.

[britelite]

Originally Posted by modrobert

I realize now perhaps they meant converting existing graphics for a port was less than %1 of the work?

Exactly this

[roondar]

Originally Posted by idrougge

One way forward would be to reimagine the game as a ZX Spectrum port. 256 x 192 resolution and monochrome should be easy enough on the RAM and DMA throughput.

You'd still not manage 381 16*512 sprites/bobs though

[OmegaMax]

Originally Posted by roondar

you'd still not manage 381 16*512 sprites/bobs though

[Miggy4eva]

wowowWOWWW! Reading the first page of this thread is so exciting. I am so crazy to see this game on Amiga 500 OCS and I'm sure it can't be arcade perfect but will surprise many people to see what the OCS Amiga is truly capable of

[DamienD]

Originally Posted by Miggy4eva

wowowWOWWW! Reading the first page of this thread is so exciting.

More like lunacy...

Originally Posted by Miggy4eva

I am so crazy to see this game on Amiga 500 OCS and I'm sure it can't be arcade perfect but will surprise many people to see what the OCS Amiga is truly capable of

Yes, you must be crazy.

If it ever gets created in some form on an Amiga (no chance on an A500 OCS though); I'll eat my shorts

[Retro-Nerd]

Very disillusioned thread. With all the amounts of sprites, animations, pre-rendered backgrouds the Neo Geo can output at once on screen. You can only produce a game that looks a bit like Metal Slug on an Amiga 500.

[Miggy4eva]

I dont know why you are picking on me as the insane, crazy one? This thread got to 7 pages without me. I LOVE the project idea and the mad-man intensity to try to achieve it. I am sure.... I KNOW that the result will surprise many people. Im hoping for updates soon!!

[nobody]

This is about the most stuff I have seen moving on A500 on a real game. If you replace the sprites with metal slug ones then probably could do a port but only 8 colors and dual playfield.

[ Show youtube player ]

PS would need more memory than a bare A500 because in this example sprites have only 1 frame. Probably a 2mb chip A1200 will do. 8 color sprites weight much less than the original ones.

[Miggy4eva]

Those waves fully animated and scrolling at 60fps are amazing but surely if they are removed it frees up so much resources for metal slug sprites and smaller animations in the background

[Master484]

Those waves fully animated and scrolling at 60fps are amazing but surely if they are removed it frees up so much resources for metal slug sprites and smaller animations in the background

The waves in the first level of Agony are drawn to the back playfield and are updated only every 4th frame, so they don't add so much Blitter stress. I think the front playfield scrolling layer consumes much more power, because so many background elements are drawn to the front playfield too. This means that the game has to do "repair blits" every time when an enemy is drawn over the front playfield background graphics, and this happens every frame. But if Agony didn't have the front playfield parallax layer, then it could draw maybe 2x more enemies, and have more RAM for animation frames.

But even with the two scrolling layers ( or actually 3 ) the speed of is good, especially in the later levels where it draws lots of stuff to screen, at times filling it entirely, but I don't think it ever slows down.

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Agony is also a good example of how with 8+8 dual playfield we can actually get a 64 color game, while keeping graphics RAM usage and Blitter stress at 8 colors. Shadow of the Beast, Lionheart and Shadow Fighter are other good examples. The 8+8 dual playfield is the most powerful mode that the A500 has when it comes to games. So for Metal Slug A500, I would definitely use it; it's the only way to fit the GFX into 512K and to keep the speed up.

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Although you can draw lots of stuff in 16 color mode too, Operation Thunderbolt is a good example:

[ Show youtube player ]

Check out for example 18:40 in the vid, where the whole screen is full of enemies, and many of them are larger than the tanks and soldiers in metal slug.

I think it runs at 17 FPS or 25 FPS at best...but still it's perfectly playable. And if it was a 8+8 color game, then it could draw even more stuff.

So for A500 drawing speed isn't the problem, but rather the small amount of RAM. But this can be solved with mid-level loading brakes. So in theory there is no reason why the A500 couldn't handle Metal Slug, if all levels are divided into segments that fit into 512K. And this isn't so bad as it might sound, games like Golden Axe and Double Dragon had multiple mid-level loading brakes too. A 10 second pause in a push-scroll game isn't so bad...only in an auto-scrolling shoot em up such loading brakes would be disturbing.

[roondar]

Originally Posted by Master484

Although you can draw lots of stuff in 16 color mode too, Operation Thunderbolt is a good example:

[ Show youtube player ]

Check out for example 18:40 in the vid, where the whole screen is full of enemies, and many of them are larger than the tanks and soldiers in metal slug.

I think it runs at 17 FPS or 25 FPS at best...but still it's perfectly playable. And if it was a 8+8 color game, then it could draw even more stuff.

The amount of bobs you can draw on a 4 bitplane screen and on a 6 bitplane DPL screen is roughly identical.

However, you are correct that using the foreground for just bobs allows you to use the blitter to clear instead of restore, which can indeed be faster if run during bitplane DMA or CPU access due to interleaved memory access (the blitter clears using every other bus cycle).

So for A500 drawing speed isn't the problem, but rather the small amount of RAM. But this can be solved with mid-level loading brakes. So in theory there is no reason why the A500 couldn't handle Metal Slug, if all levels are divided into segments that fit into 512K. And this isn't so bad as it might sound, games like Golden Axe and Double Dragon had multiple mid-level loading brakes too. A 10 second pause in a push-scroll game isn't so bad...only in an auto-scrolling shoot em up such loading brakes would be disturbing.

I'm still not convinced the A500 will be able to draw enough per frame (or two frames if you use a 25FPS display), even if it had everything in chip memory. An awful lot is happening during many of the frames in Metal Slug.

I mean, it'd be great if there was a nice port of Metal Slug, but it is setting the bar ludicrously high.

[nobody]

Not 1:1 port for sure but dropping some frames, recolor everything with less colors, drop some huge explosions, use some huge enemies as backgrounds etc then it fits.
Hard disk only and have some extra memory. I am not saying it will happen, but how it would be possible. I bet it would run perfectly on an ACA 500+, maybe with more colors too(16/32).

[Retro-Nerd]

Ruff'n Tumble runs in crappy 25fps (probably less) for a reason. No way an Amiga 500 with 1-2 MB chipram could run an enjoyable port of Metal Slug.

[Tigerskunk]

Originally Posted by Trachu

To start thinking about this I converted the graphics to unfied 16colour OCS palette and they look really good
http://download.abime.net/zone/db16.zip

What I don't get with sprite sheets as these, how are you supposed to use them on the Amiga?

I mean, shouldn't all graphics at least being aligned on a 16*n wide grid in these sheets?

[Tigerskunk]

Originally Posted by Master484

Agony is also a good example of how with 8+8 dual playfield we can actually get a 64 color game, while keeping graphics RAM usage and Blitter stress at 8 colors. Shadow of the Beast, Lionheart and Shadow Fighter are other good examples. The 8+8 dual playfield is the most powerful mode that the A500 has when it comes to games. So for Metal Slug A500, I would definitely use it; it's the only way to fit the GFX into 512K and to keep the speed up.

I concur that dual playfield is the most interesting and creative mode on the Amiga, but you need to put in LOT of work to make it look any good, and this certainly doesn't work for your run of the mill arcade game.

And especially not on something as colourful as Metal Slug.

Remember, this mode isn't even 8+8 colours, but more like 8 colours for the background, and 7 for the foreground, since one colour in fg is used for transparency..

And with only 7 for all the moving objects colours, you will lose a lot of what makes Metal Slug the game it is.

I don't think you can do a good version of this game on the A500.
On the 1200 you could start thinking about it, since you could run 4 bitplanes for the foreground and background, and have some extra oomph for drawing all the small stuff with CPU as well.



(I know a bit about this mode and its perks and flaws, since Inviyya is using dual playfield.)