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Photochrome and Spectrum pics in ST format

Posted: Wed Jul 02, 2008 7:18 pm
by ROWBEARTOE
I've attached the Spectrum 512 and Photochrome pictures I've posted (perhaps a few more). They should work on your real ST computers.

Re: Photochrome and Spectrum pics in ST format

Posted: Wed Jul 02, 2008 7:25 pm
by ROWBEARTOE
These are the Spectrum 512 files. Both the Photochrome and Spectrum pictures work on a standard 512 color ST computer. The Photochrome pictures are all in "non flicker" mode and look amazing.

Re: Photochrome and Spectrum pics in ST format

Posted: Wed Jul 02, 2008 7:33 pm
by ROWBEARTOE
These are the few Qunatum Paint pictures as well. Someday I'll make some pictures to share. 32 color 640x200 is my interest.

Re: Photochrome and Spectrum pics in ST format

Posted: Wed Jul 02, 2008 8:03 pm
by ROWBEARTOE
To make life simple, I've included the viewer programs of Spectrum 512, Photochrome, and Quantum Paint. So you can now view all 3 formats with your ST computer. These pictures and viewers are for the orginal 512 color ST computers (1985-1987). Not sure how they work or look with the later computers.

Re: Photochrome and Spectrum pics in ST format

Posted: Wed Jul 02, 2008 8:53 pm
by mrnukem
Excellent! Thank you for the pictures

Re: Photochrome and Spectrum pics in ST format

Posted: Fri Jul 20, 2012 10:38 am
by dml
I'm planning to release the sourcecode for Photochrome soon, now that I have come across it in my backups. I'll post a link somewhere on this forum when I get organised.

I don't know if I already released source for the PCS->??? convertor or just a binary module - if not, that might actually be more useful!

Re: Photochrome and Spectrum pics in ST format

Posted: Wed Aug 15, 2012 8:30 pm
by MiggyMog
That's great your releasing the code, I am sure PP will be intrigued as he uses Photochrome images on his HDD games Good stuff DML!

Re: Photochrome and Spectrum pics in ST format

Posted: Thu Aug 16, 2012 4:27 am
by DarkLord
I know this is probably inherently impossible, because of the way it works, but it
would be nice to see a newer version of Photochrome that works with accelerated
machines, once the source code is released.

Right now, I can shift to compatibility mode on my STacy and vew Spectrum and
Photochrome pics just fine, but at 32 or 40mhz. Nah, get outta here. :)

Guess it's not likely though, eh?

Re: Photochrome and Spectrum pics in ST format

Posted: Sat Aug 18, 2012 1:37 pm
by dml
@DarkLord - providing the machine has a true 8mhz/68000 'mode' and it's switchable, it could be switched just before the display starts and just after the display end, if the spare cpu cycles are needed during display. Or just switched before/after the image appears otherwise.

Machines without a true 8mhz/68000 mode - not likely as-is. The colour changes depend on precise timing but also timing stability - timing 'wobble' breaks it. Timings and wobble can be affected by caches, memory interface and other subtleties in newer cpus / accelerator boards even ignoring the 8mhz constraint.


A better way to do this colour-boosting thing generally, would be to drop PCS format(s) as persistent storage and treat them purely as caches of the display, which gets generated for a specific machine at the time of display, and either kept for next time or just binned when the display is finished. This would allow different versions of the display stuff to be made for different cpu/speed combinations, without compatibility issues with the files themselves. It would be a lot of work though, identifying and implementing all the combos, and there would probably still be a selection of hardware that it just can't work with sensibly. It would also require a much faster image generator than the current impl. to avoid long waits.

OTOH you'd get twice the colour change density on a 16mhz 68k machine, and something like 21-bit colour on the Falcon using the same sort of tricks, if other problems don't get in the way. VGA probably flickers more but the colour deltas would also be smaller, might compensate.

Re: Photochrome and Spectrum pics in ST format

Posted: Sat Aug 18, 2012 5:34 pm
by DarkLord
Okay, I kinda figured that. Just thought I'd roll the idea out there so it could be
assassinated. :)

I've got an AdSpeed accelerator in a Mega ST4. Its a great piece of hardware, very
compatible, with the ability to shift the speed down to 8mhz on the fly, and even
includes a small table where you can list programs that, when run, automatically
shift down to 8mhz. Very cool. Works great for most software. However, on SPC
or PCS pictures, even at 8mhz, cache off, it has artifacting. It works, it just has
the least little bit, so is still very "viewable". I'm not complaining mind you, just
mentioning it.

On my STacy, with the PAK 68/3 accelerator board , I'm lucky. Its compatibility
mode actually switches to a real 68000 chip plugged into a socket on the board
and is perfect!

Thanks for the reply and explanation - much appreciated. :cheers: