| |
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? |
|
| |
Dr. TerrorZ
Registered: Oct 2013
Posts: 11 |
These are just some quick thoughts.
It's possible to say it's simply an encoding and a set of character gfx that goes with that encoding, but conventions have come up over the years.
Dir art and BBS graphics (SEQ files) are certainly PETSCII.
But if a PETSCII compo is now set up then we are usually talking about the now popular executables that display a single PETSCII screen:
-Setting the background and border is ok.
-The character set itself should not be modified.
-Border changes mid-screen (raster splits) have apparently been acceptable in PETSCII competitions, so far I don't recall anybody pulling off background color splits.
-No changes to the screen area (even scrolling).
I'd think the more "pure" PETSCII is when there are no raster splits or sprites.
Animated PETSCII is obviously no longer a static screen. But it's possible that dir art/SEQ/BBS graphics have some means for animation with using just the encoding. So nothing's really that clear cut.
Technically you could also use multicolor text mode, but I guess the common understanding now is that this is not in the spirit of PETSCII. Maybe this is because the characters are not just a C64 specific thing (there are PET, VIC-20, Plus/4 graphics). Switching to multicolor would go too far from this common ground. |
| |
Smasher
Registered: Feb 2003
Posts: 512 |
my revolutionary (erm...) multicolor petscii Petscii logo POC was booted out of that petscii compo.
I don't forget ZeRyk, never! :P |
| |
TheRyk
Registered: Mar 2009
Posts: 2079 |
"If you can PRINT* it, it's PETSCII" (Groepaz many many years ago) Easy as that.
However, at last Plain PETSCII Graphics Competition 2017 there was s aubcategory in which everything showing more than one screen, scrolling or whatever demo hankypanky or gfx only BASED on CharROM would have been allowed, that's where stuff like Smasher's was dumped went ;)
*meaning Commodore BASIC V2.0 command PRINT in direct mode with default settings of a Vanilla C64 right after turning it on. |
| |
Dr. TerrorZ
Registered: Oct 2013
Posts: 11 |
Background and border colours can't be changed with PRINT. And if a few POKEs are allowed, then why not others...
PRINT would also allow control codes in the middle of the screen.
I'm not in favor of any iron rule, just saying there's no really easy definition that would fit all. |
| |
TheRyk
Registered: Mar 2009
Posts: 2079 |
sure opinions might vary and some stuff depends on situation, e.g. BBSes normally would insist on $d021 $00 whereas I don't know any competition that insisted on certain $d021 value. having different $d021 values in one screen via raster splits, however, ain't PLAIN petscii in my book, same is true for using sprites or any fucking around with other VIC registers than $D020/21 and maybe $D018 to pick from the two ROM fonts (though most will prefer the default ROM setting $15 as upper/lower-case letters are far less useful for gfx than all the symbols in $D000-$D7FF font).
Plain PETSCII Graphics Competition 2017 Scroll down to see how I defined whether something is plain or wild last time. Of course I'm also not the Pope of PETSCII definition, just some dude, setting rules for competitions I organize. If you want to run a competition, you might come up with different rules. |
| |
Jammer
Registered: Nov 2002
Posts: 1291 |
What Dr. Terrorz said ;) |
| |
Raistlin
Registered: Mar 2007
Posts: 573 |
ASCII (American Standard Code for Information Interchange), and therefore PETSCII, are from what I remember more about the text format than the character set. It’s a text format that relies only on the standard character set.
For purists I’d say that it therefore should only really rely on the characters... ie. single colour on a single colour background.
But that’s boring ... only so much you can do without changing colours ... so, yeah, whatever ;-) |
| |
Jammer
Registered: Nov 2002
Posts: 1291 |
Enabling MC doesn't contradict using character set, it's still PETSCII charset ;) |
| |
Raistlin
Registered: Mar 2007
Posts: 573 |
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 ;-) |
| |
Krill
Registered: Apr 2002
Posts: 2853 |
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. =) |
| |
Jammer
Registered: Nov 2002
Posts: 1291 |
Quoting Krillthey use some kind of FLI on char mode with ROM charset to have a bitmap mode of sorts.
Splendid idea for intro <3 |
| |
Krill
Registered: Apr 2002
Posts: 2853 |
Quoting JammerSplendid 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. =) |
| |
Jammer
Registered: Nov 2002
Posts: 1291 |
Quoting Krillit 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? ;) |
| |
4mat
Registered: May 2010
Posts: 63 |
Quote: Quoting Krillthey 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. |
| |
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) |
| |
Frantic
Registered: Mar 2003
Posts: 1628 |
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.) |
| |
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... |
| |
TheRyk
Registered: Mar 2009
Posts: 2079 |
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* |
