Incorrect tint on Dendy

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Eugene.S
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Re: Incorrect tint on Dendy

Post by Eugene.S »

I've just tested "Lion King Unl" (NewGame), Felix The Cat (U) and Prince of Persia
on a custom-made dendy with 6527P+6538 (Famicom AV PCB).

Lion King doesn't have a green tint. Felix is not very dark, and Prince of Persia works correctly.

The early revisions of all-in-one UM6561 have these problems.

Old clones was really good. But all of them made before 1994.
zzo38
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Re: Incorrect tint on Dendy

Post by zzo38 »

I think it should still be OK to use tint bits for indicating game paused, since while paused it doesn't matter the display, it only matters that it is different so that you can see the differences.
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mikejmoffitt
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Re: Incorrect tint on Dendy

Post by mikejmoffitt »

If I recall correctly, the RGB PPU was developed at the same time as the regular 2C02 so the Famicom system could be used as an arcade platform should the Famicom fall through on the consumer market. Why it does not have the color emphasis bits, I do not know.
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Dwedit
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Re: Incorrect tint on Dendy

Post by Dwedit »

It does have the color emphasis bits, except they are completely different. Instead of slightly darkening the other colors, they set R G or B to 255 for all pixels drawn. Turn on all 3 and the screen is white.
There was a thread earlier about how to detect an RGB PPU. Supposedly the RGB PPU doesn't skip 1 dot every other frame like the NTSC one does.
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thefox
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Re: Incorrect tint on Dendy

Post by thefox »

Dwedit wrote:There was a thread earlier about how to detect an RGB PPU. Supposedly the RGB PPU doesn't skip 1 dot every other frame like the NTSC one does.
Well, actually all that was really determined was that there was some kind of timing difference between the PlayChoice-10 RGB PPU and the (composite) NTSC PPU. In fact when ccovell ran some other test on his Famicom Titler (RGB PPU), the timing of it DID match the composite PPU... so at the moment we don't know of a surefire way to test for it.
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LocalH
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Re: Incorrect tint on Dendy

Post by LocalH »

I think I remember an idea being brought up that used the Zapper to test for a white screen with all emphasis bits on.
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thefox
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Re: Incorrect tint on Dendy

Post by thefox »

LocalH wrote:I think I remember an idea being brought up that used the Zapper to test for a white screen with all emphasis bits on.
Which would be just a less compatible version of asking the user "do you see a white rectangle above this text?".
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Re: Incorrect tint on Dendy

Post by Drag »

Sorry to be a pessimist again, but I don't think there's going to be any automatic way to detect an RGB PPU. Fortunately, the only gameplay-breaking difference between an RGB PPU and otherwise is the different behavior of the emphasis bits, and fortunately again, it's not gameplay-breaking if you only use one bit at a time, which is what Nintendo seemed to recommend anyway, and it might have been because of this exact reason in the first place.

If you can live with the idea that your super sweet water effects are going to look different from console to console, then you have nothing to worry about. If you absolutely 100% can't, then you could include a "Which type of NES do you have?" menu at startup, since if someone has the knowhow to play your game on an actual console in the first place, they probably are already aware of the different PPUs and how they're incompatible with one another.

If you don't want to do a menu, then offer seperate builds of your game; one for composite, one for RGB. Don't worry, because with 32-bit and 64-bit operating systems, we're all used to having seperate builds of the same thing for the same platform. :P

The reason I'm so pessimistic on this particular subject is because I don't think the effort of figuring out how to automatically detect an RGB PPU (which most people probably don't even have), either purely in software (likely not possible) or with a zapper (which is too much effort on the player, in my opinion) or whatever, it's not enough of a justification for how little of a benefit it would offer. Sometimes, things are just incompatible, and you have to compromise.
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