Crazyace

You'd get more trading a TS1000 in for a C64

Actually the mode that Rybags uses for his New year 2010 picture is pretty interesting - that seems to be combining a line of 16 colour GTIA mode ( 80 pixel low luminance ) with a line of Mode 4 ( 160 pixel 4(5) luminences ) to give a higher res picture. Of course it's not 256 colours, as the mode 4 only offers 8 luminance levels. I wonder how some of the images would look in that mode?

Sorry chroma loss is a compression artifact ( and it's to do with resolution ) - so you're not really talking about pallettes. ( If you want to bring resolution into it we could just resample the parrot picture to be 4 times coarser in X ) Anyway the picture I'm more interested in is your monochrome 160x240x16 colour one ( non interlaced ) - or was that a photoshop as well?

No problem, I calculated it at 39K cycles free at 50Hz , which is more cycles than the A8 has in total per frame, or 12K cycles free at 60Hz , which is about 40% of the total cycles per frame on the A8 per frame.

Go re-read what you wrote. You claimed that A8 has 128 colors and that's why it was okay for you to use the 128 color picture. You already drew the conclusion-- you weren't waiting for any 256 color picture; in fact, you denied that A8 has 256 color palette. Still waiting for your picture - I'm sticking with my view that the ST palette is generally superior to the A8 palette.

No, actually I wrote code for you to show Boulderdash would be possible ( this is called proof ) - and made a considered statement that any A8 game could be reproduced on the ST. ... I am talking about the conclusion you drew. It's not proof that any A8 can be reproduced; it's just that you can fit it into the frame's time although still inferior to A8. As I said, it's my opinion that any A8 game could be reproduced on the ST. The boulderdash code snippet was proof that I could replicate the Boulderdash scrolling, and still have more cpu cycles than there would be free on the A8. ( I gave you another code snippet for Mr Robot as well ... but I dont feel the need to do it for every game there is ) If you want to argue the point further feel free to provide a game that you think cant be replicated.

From my experience VGA cannot reproduce the brighter colors of the A8 and C64. Has nothing to do with "formulas" but with $FFFFFF being a nice background color for MS Word instead of a bright white. In this context, the ST doesn't use RGB via VGA , but via a TV - so that's where the comparision should be made

Oh dear, I guess it was crazy, after all there's no way the parrot could actually be reproduced on the A8 using all 128 colours at that resolution. Please feel free to provide a version of the parrot picture on the A8 , oh - and I'm also waiting for an A8 bin/image of the Kaliya picture.

No, actually I wrote code for you to show Boulderdash would be possible ( this is called proof ) - and made a considered statement that any A8 game could be reproduced on the ST. In my replies I've always given 2 cases - one interlaced(photochrome) and one not.

No problem, I never really thought about the hard drive too much ( it was a bit too expensive, so I tended to do all of my programming on a 2 floppy ST )

The thing is - on a real Atari that is a pretty good image ( and without flickering it's better than almost any C64 image would be, as it's playing to the A8 strengths ), but it's never going to be as good as the ST image , no matter how Atariksi talks up luma and chroma

There are some good tutorials somewhere - but the c2p is basically... moveq #0,d0 move.w (a0)+,d0 lsl.l #3,d0 movem.l 0(a1,d0.l),d1/d2 movep.l d1,0(a3) movep.l d2,1(a3) to transform 4 pixels via a huge table ( 512k in this case )

Isn't the Atari hard drive interface some variant of SCSI? How easy would it be to wire a SCSI drive up directly?

Just as a comparision I've prepared 3 versions of that C64 picture ( taken from the original image on CSDb rather than the processed C64 one - which does look pretty good ) STterm is a non interlaced 60Hz image. PhotoTerm is the interlaced version. A8Term is an A8 GTIA version, ( mono only - there are other people who could convert it to better A8 colour formats ) Again it's a pretty easy comparision to make

I think you're a little confused, MPEG/JPG and PC/Amiga video digitizers don't actually have anything to do with the A8 pallette ( perhaps you need to read up on your research material ) Ray tracing apps just generate pictures - the palette on ST or A8 is only how the final image is displayed. I've said it's my opinion - but please feel free to make some more 'real world' examples of images quantised to A8 and ST palette, and we can compare. ( and I'm still interested in your Kalya image on A8 )

Also the A8 is lacking in reds, which can be a lot more noticable than the 8 shade limitation on the ST. ... Nope, that's your speculation. Luminance definitely has more impact visually than having a red being off unless for some special cases where image is more biased towards reds which was probably case of the Parrot. Notice I said 'can' - the example of the parrot shows a marked inferiority of the A8 pallette compared to the ST palette. Therefore it's not speculation on my part.

Do you have this image on A8 - I'm interested in how it looks on the real machine?

Also the A8 is lacking in reds, which can be a lot more noticable than the 8 shade limitation on the ST. It's not 'my' photochrome - just an ST application for showing images. You seem to be talking about image compression here - which is completely unrelated to A8 and ST palettes. ( The only link I could think of is the interlacing of a low res colour only GTIA mode with high res luminance mode. ) As you say - you give the edge to the A8 here, that's your view. I give the edge to the ST.

Ok - so the A8 has a palette better suited for monochromatic images, and the ST has a bigger palette more suitable for full colour images. The ST still wins on the size of the palette, and it also wins on the resolution.

Lot's of that picture seems to be 80 pixels replicated to 320 - only small sections look like 160 , which is why I'm not classing it as 160*240*16. These aren't actually A8 images though, so they're not actually relevant in any way to the topic.

The ST uses a 9-bit RGB palette, right, with 3-bits per channel, not 8-bits which would be 24-bit RGB? (unless I'm misunderstanding your statement) Sorry, slip of the keyboard - I meant to say 8 levels, which is 3 bits per channel. Thanks for pointing that out.

His Linkedin page says he was 'Director of R&D' at Commodore - so that's probably a little more than a janitor

Your picture is pretty nice - How does it look on an A8? - It's not really 160x240x16 though - although you have done a really good job on the face. Here's a version for normal ST , and a photochrome interlaced version to compare with. ( I cut out the middle 320x200 from the picture , as that shows most of the colour range )

Well if you do, make a new topic for it - this one is about A8 and ST

Don't do that - Atariksi will be there lambasting the Windows 7 PC for not having 1.79MHz timers and superfast joystick ports I think the PC was winning even in the Dos era - VGA and SuperVGA were the best graphics avaible, and the cpu's were getting fast and cheaper at the same time.