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ATASCII art like PETSCII art?


Steve Mynott

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Tortuous but really simple in practice. Atari has a high resolution two color mode that can create multiple colors using artifacting. For reference you can look at Ultima III on the Atari where all colored graphics are created by artifacting.

 

The character mode screen has the same pixels resolution as the high resolution mode. The Atari allows for redefined character sets. All that is necessary is to do a picture in the high resolution colored mode and translate that into a character set.

 

There are a few constraints. If you don't use display list interrupts, you are limited to 128 unique shapes to draw the 40x24 character screen. This limits you a bit on how detailed the picture can be.drawn. Somewhere around here I think I uploaded a basic program that did this with a picture of Mickey Mouse in text mode and another that did the same in 20x24 colored character mode.

Edited by ricortes
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The character mode screen has the same pixels resolution as the high resolution mode. The Atari allows for redefined character sets. All that is necessary is to do a picture in the high resolution colored mode and translate that into a character set.

 

Uh, no, you are completely missing the point of these things, which is to use the BUILT-IN drawing characters.

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Uh, no, you are completely missing the point of these things, which is to use the BUILT-IN drawing characters.

AA seems to be particularly contentious and anal lately.

 

The question was "Is it possible on the Atari?"

My answer was both responsive and accurate to using color in character mode. I even went to the trouble of explaining how.

 

Since you seemed to have "completely missed" it, the original question was using color in character modes for atascii art vs black and white. I assumed from the pictures resolution was a prime concern so I didn't bother to include the colored GR. 2 and 3 modes which would fit your requirement that it has to be the built in character set but still require you set the mode and make a single poke to get to the graphic characters.

 

Perhaps you have a different reading of "Is it possible" then I do. I'll stick by my interpretation until the originator of the thread clarifies the point.

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Atari loses out in another regard - only 35 or so graphical characters where the C64 has about double due to it's default character set which has them instead of lower case.

 

We could use Gr. 1 or 2 for such works in 4 fg colours but Gr. 1 has the wrong aspect ratio, Gr. 2 only a quarter the number of cells of Gr. 0.

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As I understand it, on the Atari you could use a technique like Tezz is using on Manic Miner and produce a 40x25 background of different coloured blocks.

 

The issue however is how the Atari uses the Gr.0/8 hi-res mode when combined with Player/Missiles as the hue also gets combined with the two tones of the mode.

 

Therefore in the PETSCII art images you would not get the 'black' from the characters sharing the 8*8 colour block.

 

A compromise could be to use Antic 4 mode with dedicated 128 byte font but perhaps using just two colours with a both set to black but such that the PRIOR is set to place the PMs between the two playfield pairs?
But you lose half the x-resolution of the character (4 pixels rather than 8 )

Edited by Wrathchild
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You are totally missing the point!

 

You don't seem to even know what your point is.

 

Can Atari ATASCII graphics replicate C64 PETSCII art? Of course not, because it has more graphics characters and multiple text colors available.

 

Can the Atari replicate them in graphics or nonstandard text modes? To varying degrees, yes, but at that point you've gone completely off the rails because the entire point of PETSCII art is that it uses bog-standard character mode.

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There are a few constraints. If you don't use display list interrupts, you are limited to 128 unique shapes to draw the 40x24 character screen. This limits you a bit on how detailed the picture can be.drawn. Somewhere around here I think I uploaded a basic program that did this with a picture of Mickey Mouse in text mode and another that did the same in 20x24 colored character mode.

 

Don't forget that inverse video adds to the number of available shapes, adding more options. (For example, the inverse CTRL H and CTRL J give you mirror image diagonally half-filled squares).

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  • 5 weeks later...

Doing Petascii art on the Atari-8 is possible, but tricky, if you use the ICE modes. The real killer is that the Atari only has 128 characters possible, while the C-64 can do 256.

 

I came up with a palette in the PCIN (12+10) mode which basically allowed the display of all 16 of the Commodore 64 colors at low resolution. It might be possible to use a variation of this mode (or maybe something like PC0: 0+10 high res at 18 colors) to display these sorts of Graphics, especially if you take Artifacting in Graphics 0 into account.

 

Super IRG can do 14 colors, and would flicker less, but it's a matter of coming up with an optimal color palette to closely approximate the C=64 colors. Plus you'd lose out on 2 colors.

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I think redoing charset for graphics mode 12 (ANTIC 4) could (at least partially) do the job, no? :)

 

You'd get 5 colors, if you designed the letters with PF2/PF3 and double buffered and page flipped the screen. If you changed color registers every vblank, it becomes something like 8 colors plus BG.

 

Another idea: 3 character sets, with the commodore sets designed in PF0, PF1, and PF2/PF3 (you'd only have 128 characters unless you doubled the font memory to 6k). When you page flip, also alter the CHBAS pointer on each line of each page to change which colors mix together. Using this, you can get 25 colors onscreen, and about maybe 5 to 8 colors per char line, depending on which font sets you decide to mix together. Maybe also throw in some DLI color changes on each page to make the color selection a little more flexible.

Edited by Synthpopalooza
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  • 1 year later...

Doing Petascii art on the Atari-8 is possible, but tricky, if you use the ICE modes. The real killer is that the Atari only has 128 characters possible, while the C-64 can do 256.

 

I came up with a palette in the PCIN (12+10) mode which basically allowed the display of all 16 of the Commodore 64 colors at low resolution. It might be possible to use a variation of this mode (or maybe something like PC0: 0+10 high res at 18 colors) to display these sorts of Graphics, especially if you take Artifacting in Graphics 0 into account.

 

Super IRG can do 14 colors, and would flicker less, but it's a matter of coming up with an optimal color palette to closely approximate the C=64 colors. Plus you'd lose out on 2 colors.

 

 

NECRO BUMP!

 

Has anyone tried making an Extended ATASCII that matches and/or surpasses the 256 characters of C64 PETSCII? ATASCII 2 - Electric Bugaloo?

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I'm seeing a lot of multi coloured PETSCII art on twitter and the like but not similar ATASCII art (only single colour).

 

Is it possible on the Atari?

 

S

With the normal character set in the normal text, it will pretty much be two color.

 

You could get multicolor with custom character sets, Player/missile overlays, Display List Interrupts. However, that takes extra programming, and doesn't give complete color freedom that you see on Commodore.

Edited by zzip
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