puNES Emulator

Discuss emulation of the Nintendo Entertainment System and Famicom.

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lidnariq
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Re: puNES Emulator

Post by lidnariq »

4 screen seems unlikely... even in the later pirate era, adding an extra IC costs money, and most of the time it seems to be bad documentation rather than 4-screen layout.

Then again, the game seems to only boot probabilistically (staying at a solid grey screen the rest of the time), so it's kinda hard to diagnose things.
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rainwarrior
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Re: puNES Emulator

Post by rainwarrior »

The Chaos World ROM I have is mapper 1. The opening stuff is vertical arrangement, and the game map appears to use single screen, as far as I can tell. (Kinda surprised there's no bootgod entry for it?)

Edit: oh, sorry, I didn't notice the "CH", but it looks like for the Chinese hack version it ends up in the wrong mirroring mode instead of single screen 0 for the game map, on FCEUX at least.
Alyosha_TAS
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Re: puNES Emulator

Post by Alyosha_TAS »

lidnariq wrote:4 screen seems unlikely... even in the later pirate era, adding an extra IC costs money, and most of the time it seems to be bad documentation rather than 4-screen layout.

Then again, the game seems to only boot probabilistically (staying at a solid grey screen the rest of the time), so it's kinda hard to diagnose things.
So far from what I tested, the game won't boot when saveram is present. It must be getting corrupted during writing somehow?
lidnariq
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Re: puNES Emulator

Post by lidnariq »

Game seems to operate correctly in Nestopia when emulated as mapper 195 if save ram has been deleted, and not with 4-screen mirroring.

Looks like Nestopia treats Waixing's MMC3 clones' mirroring register differently. Rather than just using the LSB to select V/H, it instead uses the two LSBs to select V/H/0/1. I bet that's what's happening here.
Alyosha_TAS
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Re: puNES Emulator

Post by Alyosha_TAS »

Yeah you're right it's one screen not four screen, my mistake.

Any idea about the saveram?
lidnariq
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Re: puNES Emulator

Post by lidnariq »

My best guess is that the game expects save RAM to power up with all FFs, and emulators are giving it all 0s. But having just tried that ... it didn't help.
zerowalker
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Re: puNES Emulator

Post by zerowalker »

I just played through The Legend of Zelda, and i noticed slowdowns when many enemies where on screen (and/or did attacks like beams etc).
Also noticed Flickering on sprites quite often.

Is this how it was on the NES or is something wrong, cause it seemed to be quite a bit too obvious at times, looked more glitchy so to speak.
lidnariq
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Re: puNES Emulator

Post by lidnariq »

It is extremely likely that those flaws are authentic.
zerowalker
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Re: puNES Emulator

Post by zerowalker »

Okay, that's good to know:)

What settings solve the problems though, the overclock and unlimited sprites?
And if so, do they break stuff?

I know they don't speed up the game (at least Zelda) which is nice.
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Kasumi
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Re: puNES Emulator

Post by Kasumi »

Enabling more sprites per scanline on Zelda will cause this visual quirk. The hardware can only draw eight, so the developers placed eight in a line by the tops of doors to ensure Link's body was hidden.

Image
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koitsu
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Re: puNES Emulator

Post by koitsu »

zerowalker wrote:Okay, that's good to know:)

What settings solve the problems though, the overclock and unlimited sprites?
And if so, do they break stuff?

I know they don't speed up the game (at least Zelda) which is nice.
http://wiki.nesdev.com/w/index.php/Spri ... flow_games contains a list of games that are known to break (and what the breakage is) when using the "no sprite limit" feature. In short: do not use this feature unless you're willing to accept potential visual anomalies.

None of us who grew up with these games on the actual hardware cared much about "sprite flicker" -- we were too busy enjoying the games themselves.
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Zepper
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Re: puNES Emulator

Post by Zepper »

And then it's requested overclocking, no sprite limit, Dendy support and so on... for complaining/reporting annoyances later. After all, are you really enjoying playing the games or just enjoying the FCEUx features?
zerowalker
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Re: puNES Emulator

Post by zerowalker »

The link being shown under the door actually happened to me without any features activated.
Or well not like that though, but only one place, but it's like a black space between the "Menu" and the Map.

How is overclock affecting games, is it safer?

As for complaining.
I am not complaining, i just wanted to confirm if my issues where supposed to be there.
And if they are, then it's all fine, and any solution to that is hacking, and therefore i don't have any expectations on the emulator for that part.
The Emulator should in first priority handle NES as it's supposed to be handled as that is the goal of puNES.

Overclocking etc is a bonus, if they work, it's great, if they don't, then Maybe it can be tweaked or you may be screwed;P
I am all for options, but i care much for accuracy as the main point, so me asking about these features are not to be taken as a view away from that:)
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Zepper
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Re: puNES Emulator

Post by Zepper »

Anything that breaks the hardware rules will glitch the games. It's fun... until the time something glitches and so... "is that normal to happen"? As I said, the bad side of using an emulator for messing up the hardware defaults. A few guys fired against me regarding the lack of such features in my emulator... until now.
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tokumaru
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Re: puNES Emulator

Post by tokumaru »

zerowalker wrote:How is overclock affecting games, is it safer?
Overclocking means allowing the CPU to do more work per frame than usual, which messes with the synchronization between the CPU and the PPU, since the PPU will still generate images at 60Hz no matter what. Games often rely on this synchronization in order to implement status bars and other sorts of mid-screen PPU effects (scroll changes, pattern changes, etc.), effects that will likely glitch if the CPU is overclocked.

Emulators can cheat by providing an alternate "overclocking" method not possible on a real NES, which maintains the CPU/PPU synchronization until an entire frame goes by, and then halts the PPU for a while to give the CPU some extra time to process the game logic. This should work fairly well for games that time effects from the start of vblank or from the beginning of the frame, but may still break games that expect the time between frames to be that of the actual hardware.
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