Neo Geo to Jaguar ports in 3,2,1 GO!

[joeatari1]

So I was wandering aimlessly around the 'net and looking at the specs for Neo Geo hardware.  I found it interesting that the MVS has a 68000 running things much like the Jag does.  Seeing that the Jag also has two custom RISC chips and about four times the RAM available, it stands to reason that the Jag could run MVS or AES games pretty easily.

 

The first question I have is about capability: Does the Jag hardware lend itself to having MVS/AES games on it in all their original glory?

 

Second, If the first question is true, which games would be your favorites to port?

 

As the title says...3,2,1 GO!

[BeefMan]

No, nothing can match the raw power of the NeoGeo!

[ColecoGamer]

1 hour ago, BeefMan said:

No, nothing can match the raw power of the NeoGeo!

The above statement is absolutely true. If I remember correctly, the Neo-Geo (beyond it having a 68000 Motorola CPU) has custom hardware for accommodating massive sprites, etc.

 

Taken from Wikipedia:

 

Quote

MemoryEdit

RAM: 214 KB SRAM^[49][1]

• Main 68000 RAM: 64 KB (32 KB SRAM ×2)
• Video RAM: 84 KB SRAM
  • Main VRAM: 64 KB (32 KB SRAM ×2)
  • Palette memory: 16 KB (8 KB SRAM ×2)
  • Fast video sprite RAM: 4 KB (2 KB SRAM ×2)
• Z80 sound RAM: 2 KB SRAM
• Battery-backup save NVRAM: 64 KB SRAM

On-board ROM: 512 KB^[49]

• Zoom look-up table: 128 KB
• Fix layer graphics: 128 KB
• Z80 sound: 128 KB
• 68000 BIOS: 128 KB

DisplayEdit

The SNK custom video chipset allows the system to draw sprites in vertical strips which are 16 pixels wide, and can be 16 to 512 pixels tall; it can draw up to 96 sprites per scanline for a total of 380 sprites on the screen at a time. Unlike most other video game consoles of its time, the Neo Geo does not use scrolling tilemap background layers. Instead, it has a single non-scrolling tilemap layer called the fix layer, while any scrolling layers rely exclusively on drawing sprites to create the scrolling backgrounds (like the Sega Y Board). By laying multiple sprites side by side, the system can simulate a tilemap background layer. The Neo Geo sprite system represents a step between conventional sprites and tilemaps.^[49]

• GPU chipset:^[50]
  • SNK LSPC2-A2 (line sprite generator & VRAM interface) @ 24 MHz^[49]
  • SNK PRO-B0 (palette arbiter)^[51]
  • SNK PRO-A0, NEO-B1, NEO-GRC^[52]
• GPU graphics data bus: 24-bit^[53][54]
• Display resolution: 320×224 px (many games only use the centermost 304 px),^[49] progressive scan
• Color palette: 65,536 (16-bit) (not RGB565, but RGB666, where the lowest bit of each channel is shared, being common to the three RGB components)^[49]
• Maximum colors on screen: 4096 (12-bit)
• Maximum sprites on screen: 380^[1]
• Minimum sprite size: 16×16 px^[1]
• Maximum sprite size: 16×512 px^[1]
• Maximum sprites per scanline: 96^[1]
• Maximum sprite pixels per scanline: 1536 px^[49]
• Static tilemap plane: 1 (512×256 px fix layer)^[49]
• Background planes: Up to 3 planes,^[26] which enable parallax scrolling (large sprites can be chained together to make objects that function similarly to tilemap backgrounds)^[49]
• Aspect ratio: 4:3
• A/V output: RF, composite video/RCA audio, RGB(with separate 21 pin RGB cable FCG-9, or European standard RGB SCART cable).

Wikipedia link:

https://en.m.wikipedia.org/wiki/Neo_Geo_(system)

Edited March 20, 2022 by ColecoGamer

[ColecoGamer]

I’m sure it’s possible to port Neo-Geo games to the Atari Jaguar, but I’m no expert on its internals or how well the system could handle a game like Metal Slug, The King of Fighters, etc. Hopefully someone more qualified can answer the above questions for us. 

Edited March 20, 2022 by ColecoGamer

[phoboz]

The NeoGeo has the same CPU as the NeoGeo, and the object processor can without problem draw the same kind of large colorful sprites.

 

Architecture wise the NeoGeo is very different from the Jaguar, as the NeoGeo is designed like two separate computers (one for graphics and another one for sound). Each of one of these computers has its own direct bus to large ROM.

 

On the Jaguar, all subsystems share the same bus, and data in ROM has to be unpacked (as a cartridge can only hold 6 MB) and stored unpacked in the 2 MB RAM (when needed). So this would require special programming techniques similar to the NeoGeo CD versions of these games. The main difference is that the NeoGeo CD has 4 MB of grahpics memory, while the Jaguar has 2 MB of RAM memory in total. So it might be a challange to fit all the grahpics data in the Jaguar RAM needed for a specific scene at the same time.

 

Note that Samurai Showdown on the 3DO has less fluid animation than the NeoGeo version (e.g. they removed half of the animation frames so both fighters could fit in RAM at the same time). So a similar approach may be used for a Jaguar port.

Edited March 20, 2022 by phoboz

[ColecoGamer]

Thank you for the response, @phoboz!

 

Yes, SNK would have to downscale the graphic assets to make their games playable on the Neo-Geo CD. This is (according to NGDEVTEAM) why their later games like Gunlord and Kraut Busters can’t be ported to the Neo-Geo CD; the art assets are numerous and quite large.

 

Edit: I assume the work involved in porting these games would be too time consuming, not to mention the cuts needed in the art assets (i.e. a reduction in sprite animation frames, etc) to make them playable. Based on your response, it sounds like something similar would have to occur, if someone wanted to port one of these games to the Atari Jaguar.

 

Edited March 20, 2022 by ColecoGamer

[ColecoGamer]

Maybe someday, someone will attempt a Neo-Geo port on the Jaguar. ☺️

[Gunther]

Ninja Masters.

Edited March 20, 2022 by Gunther

[Gunther]

Top Hunter

[BeefMan]

[agradeneu]

Jaguar and NEOGEO are like apples and oranges. The sprites of NEOGEO are actually made of 16x16 tiles. It's very efficient with rendering big "sprites" with limited RAM.

Jaguar object processor works quite differently. 

 

Jaguar carts are limited to 6MB, yes, but with packed data you can reach something up to 40 MB=over 300Mbit of data. With Jaguar GD even more space would be available. Never say never to carts holding more than 6 MB. 

 

 

 

 

 

 

 

Edited March 20, 2022 by agradeneu

[agradeneu]

5 hours ago, ColecoGamer said:

Thank you for the response, @phoboz!

 

Yes, SNK would have to downscale the graphic assets to make their games playable on the Neo-Geo CD. This is (according to NGDEVTEAM) why their later games like Gunlord and Kraut Busters can’t be ported to the Neo-Geo CD; the art assets are numerous and quite large.

 

Edit: I assume the work involved in porting these games would be too time consuming, not to mention the cuts needed in the art assets (i.e. a reduction in sprite animation frames, etc) to make them playable. Based on your response, it sounds like something similar would have to occur, if someone wanted to port one of these games to the Atari Jaguar.

 

It really depends on the game. NEOGEO is a very unique hardware, the way it handles/renders sprites, so a port is not easy to begin with.  You might get better results with building up a game tailored to the strenghts of the Jaguar hardware, which is unique too. 

 

 

Edited March 20, 2022 by agradeneu

[+Gemintronic]

Rather than risking the attention of big companies and their lawyers you could always make JagStudio examples that focus on replicating Neo Geo effects.

 

Let newbies make your ports and get cease and desisted for you.  Either that or make similar yet original games in Neo Geo style.

[tonma]

If we can do it on SNES, Megadrive,  PCE or others less powerful hardware. I think the Jaguar can do it. The hardest work on each conversion is always the gfx and snd. So if you have time ...

[phoboz]

8 hours ago, tonma said:

If we can do it on SNES, Megadrive,  PCE or others less powerful hardware. I think the Jaguar can do it. The hardest work on each conversion is always the gfx and snd. So if you have time ...

Yes, but the whole point is to have a game comparable to the NeoGeo version, otherwise you can just play an existing downgraded port on a random 16-bit console.

 

The same goes for any arcade game of the 16-bit era (or even the late 8-bit era), as the arcade versions were usually far superior than the 16-bit console ports. Other classical examples are Golden Axe, Ghouls & Ghosts, Streetfighter II, Magic Sword, and even shooters like Rtype (probably an 8-bit arcade game) which had arcade quality on the PC Engine / Turbo Grafx.

 

Raiden on the Jaguar is a very good example on how this is properly done.

Edited March 21, 2022 by phoboz

[+Sauron]

I think it probably depends largely on the game, but the Jag's hardware could probably handle most NeoGeo titles without much of a problem. The biggest problem area would most likely be with the massive ROM sizes of many NeoGeo games, but as was mentioned above, that's a problem that wouldn't be difficult to solve with the JagGD. 

[joeatari1]

Good answers guys.  So it sounds like at least hardware wise the Jag could handle the games.  The games on the other hand seem like they are a bit larger than what a Jag cart can hold.  That said It seems like a Jag cart could hold some of the smaller file size games though.  According to @agradeneu a Jag cart can hold about 40 MB of compressed data.  This would be enough to have games of up to 320 Mb size.  So what games would fit that criteria?

[SlidellMan]

I can see NG.DevTeam green-lighting their games getting Jaguar ports, but SNK won't even if you have the money for licensing.

[Zerosquare]

1 hour ago, Sauron said:

I think it probably depends largely on the game, but the Jag's hardware could probably handle most NeoGeo titles without much of a problem. The biggest problem area would most likely be with the massive ROM sizes of many NeoGeo games, but as was mentioned above, that's a problem that wouldn't be difficult to solve with the JagGD. 

It's not that simple.

 

The NeoGeo AES/MVS hardware has two advantages:

- it can address huge ROMs directly

- as it's got separate busses, it can display graphics directly from ROM with zero impact on performance

 

On the Jaguar, while you technically can display graphics directly from ROM, you quickly run into performance problems because ROM access is slow and there's a single shared bus. To solve this, you have to copy graphics into RAM, much like what the NeoGeo CD does. But as @phoboz pointed out above, the NeoGeo CD has 4 MB of dedicated graphics memory, while the Jaguar only has 2 MB of memory that's shared by everything.

[phoboz]

They did it in a very clever way on the Jaguar Native Demo. Graphics data is unpacked and loaded into RAM on the go during the level. It probably works for a constant speed (quite slow) scrolling game, but in a fighting game you would notice lag when you pull off certain moves?

 

If anyone played Mortal Kombat II on the PC with less than 8 Megabyte of RAM, you know what I am talking about? On the PC however, data is read from the harddrive (even if this was a CDROM game, everything was copied to the harddrive). It would have been to slow to load from the CD during gameplay, and the question is if you could reach a similar speed attempting to unpack data from cartridge ROM on the fly. I think that Mortal Kombat II was really not that playable with to little RAM, even if they probably tried to find a clever way to cache and load game data during gameplay.

 

Note that the 16-bit console versions of Mortal Kombat II had severely crippled graphics/animations, and did not look at all like the arcade version.

Edited March 21, 2022 by phoboz

[agradeneu]

57 minutes ago, Zerosquare said:

It's not that simple.

 

The NeoGeo AES/MVS hardware has two advantages:

- it can address huge ROMs directly

- as it's got separate busses, it can display graphics directly from ROM with zero impact on performance

 

On the Jaguar, while you technically can display graphics directly from ROM, you quickly run into performance problems because ROM access is slow and there's a single shared bus. To solve this, you have to copy graphics into RAM, much like what the NeoGeo CD does. But as @phoboz pointed out above, the NeoGeo CD has 4 MB of dedicated graphics memory, while the Jaguar only has 2 MB of memory that's shared by everything.

It's not as slow as the NEO GEO CD drive, so 2MB RAM of a cart system and 4MB of a CD system are like apples and oranges. But we had the discussion before, and I still disagree with your assumption that ROM access on Jaguar was anything near as slow as a single speed CD drive. Actually on Jaguar, you can use both, RAM and ROM for gfx and sound data. On the other hand, the Jaguar CD drive is limited on 2MB RAM and even less, although it's much faster than the drive of the NEOGEO, it's hamstrung. 

 

The biggest issue with all assumptions in this thread is that they are all highly theoretical - until someone actually makes an attempt at this and has the practical experience to talk about. 

Probably, you will need a deep understanding of both hardware achitecture and how 2D gfx on both systems work. 

 

 

 

 

[agradeneu]

1 hour ago, phoboz said:

They did it in a very clever way on the Jaguar Native Demo. Graphics data is unpacked and loaded into RAM on the go during the level. It probably works for a constant speed (quite slow) scrolling game, but in a fighting game you would notice lag when you pull off certain moves?

 

If anyone played Mortal Kombat II on the PC with less than 8 Megabyte of RAM, you know what I am talking about? On the PC however, data is read from the harddrive (even if this was a CDROM game, everything was copied to the harddrive). It would have been to slow to load from the CD during gameplay, and the question is if you could reach a similar speed attempting to unpack data from cartridge ROM on the fly. I think that Mortal Kombat II was really not that playable with to little RAM, even if they probably tried to find a clever way to cache and load game data during gameplay.

 

Note that the 16-bit console versions of Mortal Kombat II had severely crippled graphics/animations, and did not look at all like the arcade version.

Mortal Kombat 2 plays fine on a SNES. Its quite close to the Arcade version, I would not call it "crippled" by any means. And a SNES has 128Kbyte main RAM.

 

PCs usually need a lot of RAM for the OS alone, consoles were much more efficent  -  so it's even like comparing apples with gigantic water melons this time  

 

You could also argue that MK2 needed an 100 MHZ CPU on PC and thus had no chance to run on a machine with a measly 3MHZ CPU like the SNES.

But it does. 

 

Edited March 21, 2022 by agradeneu

[phoboz]

1 hour ago, agradeneu said:

Mortal Kombat 2 plays fine on a SNES. Its quite close to the Arcade version, I would not call it "crippled" by any means. And a SNES has 128Kbyte main RAM.

 

PCs usually need a lot of RAM for the OS alone, consoles were much more efficent  -  so it's even like comparing apples with gigantic water melons this time  

 

You could also argue that MK2 needed an 100 MHZ CPU on PC and thus had no chance to run on a machine with a measly 3MHZ CPU like the SNES.

But it does. 

 

Yes I agree that the SNES port of Mortal Kombat II was playable, and it also featured gore which the predecessor didn't on SNES.

 

Unfortunately the graphics didn't even come close in my opinion, because the Midway T unit had both higher resolution, and 16-bit color (while the SNES has 8-bit color)

• Graphics: 400×254, 32768 colors, 53.20 Hz

Of course such assets would require twice the ammount of memory only for the double color depth, not even considering the larger high resolution sprites.

 

In addition to less fluid animations, the SNES version completely lacked the larger animated sprites like the growling trees in the background on the forest level (if I remember it correctly?)

 

Nevertheless, both SNES and Genesis have quite impressive hardware for hadling tiled graphics. Which is a very memory efficient way to store large images built up by smaller repetitive pieces. This was a winning concept further built upon from the NES 8-bit era.

[Zerosquare]

2 hours ago, agradeneu said:

I still disagree with your assumption that ROM access on Jaguar was anything near as slow as a single speed CD drive.

I've never said that. It's obviously much faster than a single-speed CD drive. But it's still not fast enough to be viable without copying the graphics to RAM first. So while the loadings would be a lot faster than on the NeoGeo CD, you would still need loadings.

 

If your game only uses a limited set of graphics at the same time, and doesn't change that set often, you may pull it off. But if it needs realtime random access to any graphic in ROM, and/or more graphics than what can fit in RAM at a given time, you have a problem.

 

Also, loadings aren't free. While you're loading those graphics, the bus cycles needed to access the ROM aren't available for playing sound or running the 68K CPU.

 

2 hours ago, agradeneu said:

The biggest issue with all assumptions in this thread is that they are all highly theoretical - until someone actually makes an attempt at this and has the practical experience to talk about.

No, it's not "highly theoretical". The slowness of ROM accesses is documented -- in the default configuration, it requires 10 cycles per access. There's also a warning in the official documentation about not putting graphics in ROM for that reason.

 

It isn't hard to demonstrate, either ; you could make a test program using Jagstudio with the same graphics both in ROM and RAM, and see how much you can display of each type before the screen starts not displaying properly.

[+CyranoJ]

Yes please - Blazing Star!

 

Will check in tomorrow for the download. Don't dissapoint!