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Forums > CSDb Discussions > the limits of PETSCII
2019-12-14 12:30
oziphantom

Registered: Oct 2014
Posts: 478
the limits of PETSCII

How far can one go before it is not deemed "just PETSCII"?

Is it as long as one doesn't touch the char set in anyway? So any register modifications are fair game?
Or registers must be stock apart from colours?
Can't animate/colour change unless it is hardware supported? or even hardware supported changes are not legal?
 
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2019-12-15 13:18
Raistlin

Registered: Mar 2007
Posts: 555
It is.. but a purist would expect that the PETSCII text file (not executable) could be viewed in any software or on any platform that features that font.

But.... probably 90% of PETSCII pics would be disqualified under that so, yeah, all gloves are off I’d say ;-)
2019-12-15 13:39
Krill

Registered: Apr 2002
Posts: 2839
Semi-off topic: On PET, where no bitmap mode nor redefinable charsets exist, they use some kind of FLI on char mode with ROM charset to have a bitmap mode of sorts.

Pretty sure that won't qualify as PETSCII by any stretch of the definition, though. =)
2019-12-15 13:42
Jammer

Registered: Nov 2002
Posts: 1289
Quoting Krill
they use some kind of FLI on char mode with ROM charset to have a bitmap mode of sorts.


Splendid idea for intro <3
2019-12-15 13:52
Krill

Registered: Apr 2002
Posts: 2839
Quoting Jammer
Splendid idea for intro <3
Well, it wouldn't save much memory if doing FLI every rasterline, compared to bitmap mode. But you can go for every 2nd line or fewer, of course. With worse and worse matches to your intended original bitmap. =)
2019-12-15 14:28
Jammer

Registered: Nov 2002
Posts: 1289
Quoting Krill
it wouldn't save much memory if doing FLI every rasterline, compared to bitmap mode.


You can always try to match best 40 byte sequences in ROM. In that case you only store 200 offsets out of which you further build whole bitmap. I'm just not sure what kind of crap would be the result :D Not very handy for Didi's compo, surely, but for regular 4k or 1k even? ;)
2019-12-15 15:16
4mat

Registered: May 2010
Posts: 63
Quote: Quoting Krill
they use some kind of FLI on char mode with ROM charset to have a bitmap mode of sorts.


Splendid idea for intro <3


Yeah that was something Ultra came up with in our "No Pets Allowed" demo. IIRC the display area changes depending on the X/Y dimensions of the graphics. (eg: the Twister screen is only that area of the screen, similar to offset displays on the Vic-20 I guess) The source to the gfx mode is in the with the demo.
2019-12-15 19:16
Smasher

Registered: Feb 2003
Posts: 512
Quote: Enabling MC doesn't contradict using character set, it's still PETSCII charset ;)

Jammer's sainthood now!
(don't know how to translate "Santo subito!" it->en better than this)
2019-12-16 13:28
Frantic

Registered: Mar 2003
Posts: 1627
I know there is no independent point of reference that could be used to establish some kind of objectively true definition of "pure petscii", but in my book the closest thing to pure PETSCII graphics would be to have background color set to black (like it is in most terminal software) and then (like Groepaz had suggested) whatever can be printed *sequentially* with the PRINT command, including control characters like switching upper/lower-case. At least that would be the BBS-related definition of "pure petscii". (DIR art is a much more restricted variant of this, and I wouldn't call it "pure petscii". If I remember correctly there are also a number of petscii symbols that aren't allowed in filenames... but I could be wrong about that.)

The other possible definition would be "anything that could be shown using only the PETSCII charset" (e.g. putting values in screen ram and color ram) and having $d020/$d021 set to fixed values, and VIC set to normal char mode. This is how you see your PETSCII graphics when you use most of the available "PETSCII graphics editors" (even if the actual file format when saving the file may be sequential SEQ files).

From some kind of logical point of view one could argue for a third possibility: that the charset itself is what counts the most when one is talking about pure PETSCII, even if the charset would be removed from its C64 context in some way, but in practice I don't think that's a very relevant definition as it doesn't rhyme well with the particular cultural practices associated with the Commodore 64, which is where the idea of "PETSCII graphics" emerged.

(NOTE: I don't care half as much about this topic as this post may give the impression of. Feel free to define it any way you want.)
2019-12-16 15:19
Rudi
Account closed

Registered: May 2010
Posts: 125
I don't see why more than one screen shouldn't be a problem. But let different competition rules define the details. I dont have any opinion about the historical context of petscii used in the c64-scene, I wasn't an Petscii artist from 80s-90s. So.. the general definition of petscii (from wikipedia et al.) as I recall is defined by its character set. It's not defined by its resolution nor colors. Imho, just saying petscii without additional details and one could interpret it in a variety of ways. Also as far as I understand petscii was based on some ascii version in the 60s...
2019-12-16 16:34
TheRyk

Registered: Mar 2009
Posts: 2070
Quote: Jammer's sainthood now!
(don't know how to translate "Santo subito!" it->en better than this)


Infidels! (Hope that fits the German: "Ketzer"!)
*looks for torch and pitchfork in his Torquemada lynch mob kit*
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