Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Secret colours of the Commodore 64

aaronbell.com

Post reply on HN
Print view View original

41–50 of 100 posts

Re: Secret colours of the Commodore 64

#41

Post by dirtbox »

anjc wrote: post #23
dirtbox wrote: post #19

Earlier quoted context omitted.

You could use this same palette flicker on the speccy to remove the attribute clash and create new colours, I remember someone demoing a more or less pixel perfect version of Super Mario World, albeit with a black background. The spectrum was capable of all sorts of odd things that were never intended. http://tarjan.uw.hu/zx_gfx_modes_en.htm

That's very interesting. I'm always impressed at how dedicated some people are to old systems too. My Spectrums haven't been touched in 15 years and here's people making graphics cards for them still.

There's even a new speccy coming out. http://www.specnext.com/

Re: Secret colours of the Commodore 64

#42

Post by corysama »

Lerc wrote: post #9

I once toyed with Temporal dithering on VGA ModeX. While the bullet point listed resolution for standard VGA was 320x200. Hitting the hardware registers and paying the price of a rather peculiar addressing mechanism for pixels you could get a lot more(and double buffering to boot). 320x240 was the most common tweaked mode, because it gave you square pixels and page flipping. At the edge of what momitors could handle…

I vaguely recall seeing a DOS demoscene demo that filled the 320x200 screen with a letterboxed 256x200 gradient. Then it slammed the actual display frame data into the VGA 256 color pallete one line at a time on each horizontal sync. The result was an effective 18-bit color resolution image from a 256-color device. (I think MCGA didn't actually have 24-bit palletes)

Of course, it meant you had to spend 90% of the frame updating the pallete registers and only had the vertical blank time to draw everything into the frame buffer. But, the focus of the demo was the idea that high-color was at all possible on VGA hardware.

Re: Secret colours of the Commodore 64

#43

Post by brusch64 »

drudru11 wrote: post #25

This is cool, but I've never understood why people like the C64 palette. It looked washed out to me. I guess people grow to like the look of the machines they have fond memories of. (Apple II, Coco, Sinclair) The Amiga was the first machine to really impress me with its pallete.

Well the Amiga had 4096 colours. The colour palette was of course more flexibel.

But if you compare the C64 palette with other 8 bit computers of the time, it looks better for me. And as he explains in his article, it is easier to generate more realistic looking pictures with it than with a more vibrant colour palette.

Re: Secret colours of the Commodore 64

#44

Post by Doctor_Fegg »

ENTP wrote: post #33

Off topic-ish: There was a trick you could use on the Atari ST to display more than the allowed number of colours - you reloaded the palette data on each horizontal interrupt. Could this have been used on the C64 also?

You could do this on the Amstrad CPC (and many people did, mostly but not exclusively demo coders). The CPC had a palette of 27 possible colours, of which 16, 4, or 2 could be shown at once, depending on screen resolution (160px, 320px, 640px respectively, all x 200px). By reprogramming the palette selection on the fly, using two successive writes to output port &7F00, you could change the palette as the electron beam moved down the screen. You could even do it mid-screen row if your timing was good!

Re: Secret colours of the Commodore 64

#45

Post by andretti1977 »

These were the "magics" you were able to do at that time! You could achieve amazing and unexpected results going beyond common software programming, mixing software with phisical effects for example. This was the reason the author of the article got so impressed. I don't know what kind of todays's unconventional programming technique can achieve such a wow effect! Side note: i was 14 too in 1991...incredible times, such as mid '80s!

Re: Secret colours of the Commodore 64

#46

Post by avian »

anjc wrote: post #16

Cool article, but the Spectrum really only had 7 colours and black. And at the time I hated the Commodore 64's colour palate (and any non ZX Spectrum palate, until I saw the beautiful SAM Coupé's) so I guess it's a matter of preference.

Sinclair ZX Spectrum had a palette of 15 colors. 7 base colors, plus 7 "bright" versions, plus black (bright black was the same as normal black).

Re: Secret colours of the Commodore 64

#48

Post by inoop »

corysama wrote: post #42
Lerc wrote: post #9

I once toyed with Temporal dithering on VGA ModeX. While the bullet point listed resolution for standard VGA was 320x200. Hitting the hardware registers and paying the price of a rather peculiar addressing mechanism for pixels you could get a lot more(and double buffering to boot). 320x240 was the most common tweaked mode, because it gave you square pixels and page flipping. At the edge of what momitors could handle…

I vaguely recall seeing a DOS demoscene demo that filled the 320x200 screen with a letterboxed 256x200 gradient. Then it slammed the actual display frame data into the VGA 256 color pallete one line at a time on each horizontal sync. The result was an effective 18-bit color resolution image from a 256-color device. (I think MCGA didn't actually have 24-bit palletes) Of course, it meant you had to spend 90% of the fra…

X14 by Orange?

https://www.youtube.com/watch?v=LRPhB1KkxMc

Re: Secret colours of the Commodore 64

#49

Post by rusk »

flashman wrote: post #37

> Sidebar: A note on frames per second. The European PAL C64 updated at 50fps, whereas the US NTSC systems updated at 60fps This is because alternating current is 50Hz in PAL countries (eg Europe), and 60Hz in NTSC countries (eg America). Analogue TVs vertical refresh rate was synced to the AC frequency for a bunch of practical reasons, which meant gaming consoles had to send signals to the television at either 50Hz…

> for a bunch of practical reasons

Basically makes it cheaper to build. You have a natural frequency there to use, and you don't have to come up with all this additional hardware to smooth out the existing frequency and come up with a new one.

I think there was a flip-side to this ... though NTSC had faster refresh, PAL had a higher resolution (more lines). I'm not sure, but I think this may have been a tradeoff.

Re: Secret colours of the Commodore 64

#50

Post by TazeTSchnitzel »

mikejmoffitt wrote: post #10
TazeTSchnitzel wrote: post #2

This overlooks a key detail, namely interlacing. The C64 wasn't producing 60 frames per second, but rather 60 fields : sets of odd or even scanlines. So on the CRT TVs of the time, you'd get one colour on the odd scanlines, and another on the even scanlines. Scanline striping, essentially.

That isn't quite correct. The C64 outputs a progressive-scan image, which is a hack on top of NTSC or PAL. In this configuration, there are only even or odd fields, which double-strike the same area. Thusly, it is 60 fields per second, and since only one field forms the full frame, it's 60 frames per second as well. There is no scanline striping; that is strictly an artifact of poor NTSC capture devices (like most HD…

A progressive-scan image emitted as an interlaced image results in, well, an interlaced image. That the scanline pairs are usually identical merely means that it's wasting vertical resolution.

And nonetheless a CRT from the time would show these as different scanlines.

Post reply on HN