One pixel line missing in Snaphots

Post by **pagefault** » Mon Jan 15, 2007 10:21 pm

It's being corrected. Just wait for 1.51.

filouk · Post by **filouk** » Mon Jan 15, 2007 10:45 pm

Nice ! You guys really do great work.

creaothceann · Post by **creaothceann** » Mon Jan 15, 2007 10:46 pm

Thanks!

filouk · Post by **filouk** » Sun Jan 28, 2007 7:17 pm

Well I've just tried to take a DKC3 snapshot using the lastest ZsNes version v1.51, and it still shows the black line at the bottom, instead of the true bottom line.

Deathlike2 · Post by **Deathlike2** » Sun Jan 28, 2007 7:28 pm

Use the old graphic engine to take the picture with if you cannot live w/o it. We know this is an issue with the new graphics engine.

filouk · Post by **filouk** » Sun Jan 28, 2007 7:34 pm

Yes, it works ! Thank you very much !

Oh no it's ugly.

Dirtie · Post by **Dirtie** » Tue Jan 30, 2007 1:43 am

Big <3 for (almost) showing all the lines correctly, I've been waiting for this for quite a while. However, as seemed to be mentioned above, the "garbage line" doesn't quite appear how it would on a real snes capture (colour is either wrong, or for games that usually use it to actually display stuff it still just stays a single colour). I know I'm just being rather nitpicky here, but is there any chance of it ever displaying properly

?

Otherwise, what are the disadvantages of using the old graphics engine? Is it any less accurate in cases?

Deathlike2 · Post by **Deathlike2** » Tue Jan 30, 2007 2:03 am

The Old Graphics Engine uses a 13-bit color palette, instead of 15-bit for speed reasons. A game that comes to mind would be CT where it becomes rather noticable.

Edit: Forgot to mention FF3/6 as well.

Dirtie · Post by **Dirtie** » Tue Jan 30, 2007 2:31 am

I see.

I also just noticed in the release topic for 1.51 that a fix is being worked on. Good job

filouk · Post by **filouk** » Tue Jan 30, 2007 5:07 pm

Yes that's good news !

Might be a stupid question, but isn't the Super NES supposed to be 16-bits ? So how come the engine is 15 bits ?

Firon · Post by **Firon** » Tue Jan 30, 2007 5:47 pm

The SNES can only display 15 bits of color.

Post by **Agozer** » Tue Jan 30, 2007 7:29 pm

The SNES CPU is 16-bit, meaning it uses 16-bit instructions.

filouk · Post by **filouk** » Tue Jan 30, 2007 8:51 pm

I see... The SNES has a total of 32768 colours, and ln(32768) / ln(2) = 15 bits.

Cyrus · Post by **Cyrus** » Tue Jan 30, 2007 9:01 pm

filouk wrote:I see... The SNES has a total of 32768 colours, and ln(32768) / ln(2) = 15 bits.

16 bit colour has 5 bits for red/green/blue (15 bits) and the other 1 bit is used for transparencies.

Edit: Yes thant means 2^5 = 32. So the colour range would be from 0 to 31. I don't see where you're going with this.

filouk · Post by **filouk** » Tue Jan 30, 2007 9:07 pm

Ok so there are 32 levels of red, 32 levels of green and 32 levels of blue, making a total of 32^3 = 32768 colours.

Firon · Post by **Firon** » Tue Jan 30, 2007 9:22 pm

Cyrus wrote:16 bit colour has 5 bits for red/green/blue (15 bits) and the other 1 bit is used for transparencies.

Not necessarily. If it's RGB565, then there's an extra bit available for green (which is the color our eyes are most sensitive to).

Cyrus · Post by **Cyrus** » Tue Jan 30, 2007 9:26 pm

Firon wrote:
Cyrus wrote:16 bit colour has 5 bits for red/green/blue (15 bits) and the other 1 bit is used for transparencies.
Not necessarily. If it's RGB565, then there's an extra bit available for green (which is the color our eyes are most sensitive to).

Yep, but I'm wondering how can you have transparencies with RGB565 then?

Deathlike2 · Post by **Deathlike2** » Tue Jan 30, 2007 9:29 pm

Well, in theory you could have 8-bit transparencies.. the problem is the palette isn't big enough to make it possible in the case of the SNES. 15-bit color is plenty enough to do transparancies.

Cyrus · Post by **Cyrus** » Tue Jan 30, 2007 9:31 pm

Deathlike2 wrote:Well, in theory you could have 8-bit transparencies.. the problem is the palette isn't big enough to make it possible in the case of the SNES. 15-bit color is plenty enough to do transparancies.

Wouldn't RGB565 take the full 16 and not leave anything for transparencies? That was my question...

Deathlike2 · Post by **Deathlike2** » Tue Jan 30, 2007 9:34 pm

Dude, you're not paying any attention. Potential for transparancies is limited to the palette you are working with. In the case of SNES, RGB555 is what is used, the other unused bit is used for something else internally to the emulator, and not the actual (SNES) system itself.

Firon · Post by **Firon** » Tue Jan 30, 2007 9:49 pm

I think he's thinking of an alpha channel, which uses extra bits (24-bit color + 8-bit alpha, for example).

Deathlike2 · Post by **Deathlike2** » Tue Jan 30, 2007 9:53 pm

Firon wrote:I think he's thinking of an alpha channel, which uses extra bits (24-bit color + 8-bit alpha, for example).

There isn't one in this instance IIRC. The 13-bit engine is probably RGB444 of some sort with the extra bit used for add/sub.

The best analogy is to consider some artist drawing a picture. If he had an "8-bit" palette, he would have access to like 4-8 shades (2-3 bits) of red (darker/brighter). With the "13-bit" palette, there would be 16 shades (4-bits).. and the "15-bit" palette", there would be 32 shades (5-bits). There is no "transparency bit" here.. just darker/brighter shades to appear like transparancy is applied.

Edited for errors.

filouk · Post by **filouk** » Tue Jan 30, 2007 10:49 pm

I thought that with a 15 bits palette the artist would have access to 32 shades of red, 32 of green and 32 of blue.

Deathlike2 · Post by **Deathlike2** » Tue Jan 30, 2007 10:51 pm

Arg, that's what I meant... my brain is in another world at the moment.

creaothceann · Post by **creaothceann** » Tue Jan 30, 2007 11:34 pm

Agozer wrote:The SNES CPU is 16-bit, meaning it uses 16-bit instructions.

Actually it's because the CPU registers are 16 bits wide. The SNES also has 1-byte instructions.

Cyrus wrote:
Firon wrote:
Cyrus wrote:16 bit colour has 5 bits for red/green/blue (15 bits) and the other 1 bit is used for transparencies.
Not necessarily. If it's RGB565, then there's an extra bit available for green (which is the color our eyes are most sensitive to).
Yep, but I'm wondering how can you have transparencies with RGB565 then?

On the one hand there's the output device. The SNES takes 5 bits per color channel to determine the output color. The 16th bit of the source is ignored.

On the other hand you can tell the SNES to render the current VRAM data in different ways, for example a forest once with water in a lake and once without water in said lake. By adding the two resulting screens you get transparent water, still at 15 bpp.

+

=

RGB8888 etc. is just how the pixels are stored. Since true color requires only 24 bits, the rest is used to indicate the pixel's opacity. Very useful for image editing, but not for output.