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JJohnson

Newby Question on NES Ports

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I'm very new here, so I thought I would ask here. What would a given NES classic game look like on Atari 7800? Let's say: Mega Man 1-6, Castlevania, Contra, Double Dragon, Batman, TMNT 1-3, Battletoads, Bucky O'Hare, Final Fantasy 1-3, StarTropics, Disney games (Rescue Rangers, DuckTales, etc), Tecmo Bowl, Adventure Island, Bubble Bobble, Blaster Master, Dragon Warrior, Ninja Gaiden, River City Ransom, Ghosts N Goblins, Bionic Commando, and even Metroid, Super Mario 1-3, Donkey Kong 1/3 et al?

 

From what I read of the tech specs, the 7800 could display more colors at once, so theoretically the games should look as good or better than the NES, like the Master System.

 

And has anyone thought to port any of those games over to the 7800, and if as a ROM, including the upgraded audio chip?

 

Thanks,

 

JJ

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I'm sorry to say none of what you are mentioning works the way you think it does or could.

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Nobody thought about it till now.

Check out Rikki and Vikki 7800 for extreme graphics and sound.

Dk has been redone graphics and sound.

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Probably better to let one of the devs who've developed for all these systems explain it, but I'll try to give my best non technical explanation

 

All three are competitors from similar timeframes. The NES was released as the Famicom in Japan, but took until 1985 to get released in North America and 1986 to be wide released here. The 7800 was intended for release in 1984 but outside of a test market before the company was sold, didn't really see release until 1986. I can't remember the dates for the SMS, but I think the Mark III was out in Japan in 1983 as well, but 1986 in North America. In the SMS's case, I *THINK* the SMS has some upgrades, but I'm not sure about this.

 

The NES and SMS are more "fixed form" type systems, meaning they tend to play tile based side scrollers really well, but start to struggle when playing other types of games. The 7800 is more "free form" in that it gives developers flexibility, but that's a lot of overhead for a little 8bit system so there can sometimes be sacrifices that are made. The 7800 can play title based side scrollers, but it's more work for the system. On the other hand, it's ability to pull off display tricks is why you see so many damn flight simulators on that system. All three systems have churned out games with parallax scrolling, something people took notice of on the 16 bit systems ... then developers started doing it on the 8bits too.

 

In terms of graphics, the 7800 and SMS have a larger colour palette (256 colors) than the NES (52 colours). The SMS can put more colours on screen at once (I think 32 colors) without tricks than the NES or 7800 (25 colours). Both the NES and SMS have default 256 pixel wide displays and I don't believe any other resolution modes. The 7800 has 160 pixel wide modes, which most games use, giving 7800 games a lower, fat pixel look. However, the 7800 also has 320 pixel wide modes and the highest resolution games on the 7800 are higher than either the SMS or NES. However, there are colour limitations in these high resolution modes. The Homebrew Rikki and Vikki runs in this mode and looks terrific.

 

The 7800's biggest advantage over the other two is its ability to move objects around the screen. There are 7800 games with dozens upon dozens of moving objects that don't have flicker and often don't have slowdown. With the SMS and NES, they get around limitations by flickering and you can't also get a "herky jerky" result with really big boss creatures and the like.

 

In terms of sound, the NES is probably the best, followed by the SMS then the 7800. The 7800 has 2600 sound for compatibility with the 2600, though GCC always intended that the system could include sound on the carts ... something the tramiels didn't pay for. I believe all three have examples of extra RAM. The SMS and NES also have games with battery saves but that's a cheapness function. NES and SMS carts tend to be quite a bit bigger on average, but that's a "cheapness" function as well. Rikki and Vikki is as big as any NES or SMS game is. Most NES games have some form of memory mapper to give the NES capabilities not in the stock system. Don't know if SMS games do. No contemporary 7800 games do, though Rikki and Vikki does as well.

 

I think the NES and 7800 have similar RAM, the SMS has a little bit more ... but this was in an era where they were all trying to do more with less.

 

All of those things aside, there's still a major factor to consider.

 

1. Nintendo was an A+ developer and had every major developer lined up making NES games. And their 2nd through 7th generation games, continuing to push the system and exploit results because the market was there and there was incentive to standup

 

2. Sega was also an A developer and - in Europe in South America - also had sizeble third parties. And they pushed the bounds as well

 

3. Atari treated the 7800 has a cash cow to fund computer development. Labels were black and white, manuals didn't have screen shots, games weren't bigger than 144K, cheap developers were hired and almost no third parties took chances and would have received little support from Atari if they did.

 

If Nintendo had told Shigeru Miyamoto to make a 7800 game, put it on a three megabit cartridge with a mapper and take 18 months to develop it, the results probably would have been different than what you saw on the 7800 ... regardless of technical differences.

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Thanks for the replies, I appreciate it. I know that the 7800 didn't really get good development, so I guess my question should be: is there anyone working on a homebrew 7800 port of any of those NES games maxing out the system?

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Posted (edited)

Thanks for the replies, I appreciate it. I know that the 7800 didn't really get good development, so I guess my question should be: is there anyone working on a homebrew 7800 port of any of those NES games maxing out the system?

 

It does happen sometimes. For example, Bentey Bear's Crystal Quest came out of a discussion as to whether or not the 7800 could play a game like Adventure Island or Monster Land. It morphed into the original homebrew we all love.

 

 

https://www.youtube.com/watch?v=ixA3EajvCWw

 

http://atariage.com/forums/topic/190094-wonderboy-on-the-7800/

Edited by DracIsBack
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I actually did the reverse; I first created Frenzy on the Atari 7800, and then ported that to the NES.

 

I have the Super Mario Bros source code, and actually got it to compile using the 7800's compiler, but the video / sound drivers are still the NES versions. I always meant to attempt to convert it to the 7800 just to prove that it can be done, but I never got around to it.

 

With a lot of work, I still believe it can be done. It may not look as good in 320 mode due to the limited color palette, but it would work.

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DracIsBack got most of it, but I'd add that all three consoles (NES, SMS, 7800) in this hardware class have different strengths despite being released within a few years of each other.

What the 7800 is good at relative to the other two is not just the ability to display large numbers of moving objects - but large numbers of wide moving objects. You can also have a higher resolution display at the penalty of a reduced color count and sparse layout.

However, it has extremely poor support for tiled backgrounds and your overall performance will be lower since Maria (graphics chip) has to kick the CPU off the bus to render. So even though the NES and 7800 both have a 6502 style CPU running at the same speed, the 7800 will perform noticeably worse.

In some ways it's an 8-Bit class Jaguar.


Could the 7800 run a game similar to the ones you listed? Yes
Would it look and sound the same? No

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DracIsBack got most of it, but I'd add that all three consoles (NES, SMS, 7800) in this hardware class have different strengths despite being released within a few years of each other.

 

What the 7800 is good at relative to the other two is not just the ability to display large numbers of moving objects - but large numbers of wide moving objects. You can also have a higher resolution display at the penalty of a reduced color count and sparse layout.

 

However, it has extremely poor support for tiled backgrounds and your overall performance will be lower since Maria (graphics chip) has to kick the CPU off the bus to render. So even though the NES and 7800 both have a 6502 style CPU running at the same speed, the 7800 will perform noticeably worse.

 

In some ways it's an 8-Bit class Jaguar.

 

 

Could the 7800 run a game similar to the ones you listed? Yes

Would it look and sound the same? No

TailChao - Given what you've said, is the issue with backgrounds that is has trouble rendering high detail backgrounds, or all backgrounds? Could something like this:

be done or is it a tough thing to accomplish because of the background? If the background is a problem, could it be over come using simpler platforms?
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TailChao - Given what you've said, is the issue with backgrounds that is has trouble rendering high detail backgrounds, or all backgrounds? Could something like this: [...] be done or is it a tough thing to accomplish because of the background? If the background is a problem, could it be over come using simpler platforms?

Sort of.

 

The issue is that Maria can only perform straight texture draws (render one item in a specified location, size, and palette) or draw "Character Strips" which are one horizontal group of tiles which all share the same palette. So horizontal palette changes are expensive. Drawing in Character Mode is also way slower than doing straight draws.

 

Generally, the more detailed your background - the less render time you have available for whatever else you'd like to draw on top of it, and the less CPU time you'll have for running your game logic. You also have to move your draw commands horizontally by hand to scroll, but this isn't too big an issue and it could be hardware'd around.

 

The example you provided would be the "ideal" but that doesn't mean more detail is impossible, there's just a tradeoff. Whereas on the NES and SMS you get a scrollable tilemap "for free" with configurable tile attributes.

 

RnV_20.png

Using Rikki & Vikki as an example, if you look at the stage layout there's as few horizontal palette changes as possible to improve the drawing performance. Most of the background is also black, so the game only draws exactly what it needs to. If it ran in a lower resolution mode we'd have more render time to make a more detailed background.

 

All these restrictions only have to be taken into account on the 7800 while on the other two there's no need to really care. This doesn't mean their tilemaps aren't without their own limitations, but they're much better suited to where game visuals were going at the time.

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Posted (edited)

However, it has extremely poor support for tiled backgrounds and your overall performance will be lower since Maria (graphics chip) has to kick the CPU off the bus to render. So even though the NES and 7800 both have a 6502 style CPU running at the same speed, the 7800 will perform noticeably worse.

 

This is an extremely important point. And I think TailChao explained it perfectly, but because I've seen comments like this taken and misinterpreted on youtube, facebook and even Atariage as "I hear the 7800 can't scroll" and "I hear the 7800 can't do tiled backgrounds" and "I hear it can't do tile based side scrollers", I want to reiterate again: that's not the case. And there are lots of examples of the 7800 doing it. But it wasn't designed to be hardware that focused on fixed form, tile based side scrollers the way the other two were.

 

Saying what TailChao said a different way: there's a difference between saying "could MARIA play an acceptable version of game N" and "can it do a pixel-for-pixel-frame-for-frame-color-for color version of game N"

 

The answer is usually that the former is probably perfectly possible - with effort. The latter is not.

 

There are plenty of examples of NES like games on the 7800. Not saying "the NES wouldn't do them a different way, more easily, with more colors or resolution." Just that people have a habit reading threads like this and then assuming the 7800 can only play Ms Pac Man or Centipede and do nothing else. :-)

 

http://www.youtube.com/watch?v=HjqmpLAVwxg

 

http://www.youtube.com/watch?v=qLF3HJVCwOQ

 

http://www.youtube.com/watch?v=_EellOX4-zA

 

http://www.youtube.com/watch?v=94-pWVgZNys

 

http://www.youtube.com/watch?v=EA-VEQT7mV4

 

http://www.youtube.com/watch?v=3TUybTbEm74

 

http://www.youtube.com/watch?v=l17lcC_ih0g

 

http://www.youtube.com/watch?v=VQMW-jqb-HA

 

http://www.youtube.com/watch?v=eGGZFlK-_ek

 

How a lot of these games work around the limitations with regards to the tiled backgrounds is they work in the lower 160 pixel modes, sometimes reduce colors used on screen or "window" the display.

 

 

 

Edited by DracIsBack
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A few years ago, when we had one of our endless "7800 vs" discussions, one of the contributors commented that a great port for the 7800 would actually be the Sega game, Space Harrier.

 

In this case, the game has a "first person" perspective where it's a lot of sprites moving around on a relatively simple background with some display tricks to give it that first person look. MARIA wouldn't render/scroll a detailed tile display for the background and instead focus on chucking around a lot of sprites simultaneously.

http://www.youtube.com/watch?v=usiaujwjv4M

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Another example was the original Legend of Zelda. Again, the game really just kind of moves from screen to screen, there aren't a lot of colors being used and the 7800 would probably do a better job rendering the sprites without flickering than the NES.

 

Someone once did a demo of the map on 7800 but I think Nintendo's lawyers killed that

 

https://www.youtube.com/watch?v=ZWLHwAH-9GE

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Posted (edited)

Basically, if you're willing to sacrifice resolution (i.e. 160 pixels instead of 320), your colors are MUCH more richer.

 

For example, Bentley Bear uses 160A backgrounds and 160B sprites.

 

For tiles, that's 3 colors + a background (which can change between zones, as is done in that game) for each displayed set of tiles. You can have multiple sets of displayed tiles with different palettes within each zone, but the more different ones you have, the more Maria time it takes.

 

For sprites, that's 12 colors and you can choose between 2 palettes for each sprite. The only drawback is that pixels are twice as wide as high.

 

I've used 320B mode for some of my games, and that is a little more tricky. You only have two palettes with at most 3 colors in each (without some trickery, you only have 2). Rikki & Vikki uses this mode in a masterful way, and I'm amazed with what they have done. Scramble uses 320B mode for everything, with transparency for the scrolling playfield.

Berzerk / Frenzy uses 320A mode. (7 palettes, one color in each). I needed to fill the screen with the mazes, and 320B mode would have taken too long. There is a bit of slowdown already without it. This is why the walls are only one color. I could have broken up the tile mode into different sections while drawing the maze to get the additional colors, but that would have taken too much Maria time for all of the different tile modes that would need to be added to the DLs.

 

I guess the point is what TailChao said in his first response. The 7800 could run just about anything the others could. It's just a matter of, if you need to have a limitation, where it would be: the number of colors, or the resolution.

 

Sound is a horse of a different color. Including a Pokey (or another sound chip like BupSystem) would take care of the sound issue.

Edited by PacManPlus
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