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Atari coding BBS
| Re: Scroll text techniques |
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Posted by: ggn
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Oct,25.2007-11:23
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Ok, here's the code (off the top of my head ;) for a fast-ish 8x8 font 1-plane scroller, scrolling by one pixel per vbl:
(Assuming ST low, a0 is the scroller screen address, and see bleow for d0. Also, no screen flipping used :)
lea 8*160(a0),a0
rept 8
lsr.b #1,d0
i set 152
rept 20
roxl.w i(a0)
i set i-8
endr
endr
So is that all? Not enirely! To get this code to work you have to rotate your font by 90 degrees, so each byte must contain one vertical strip (instead of one horizontal). Then you have to load each vertical strip of one character in succession each time the above snippet runs (once per VBL that is). That is, byte 1 in the first vbl, byte 2 in the second etc. Finally, every 8 VBLs you have to fetch the next character in your text array and calculate the font data address.
If anyone wants I can find and post the full code here (this was from memory) :)
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Topic
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Posted by
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Date
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Scroll text techniques
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Vincent Riviere
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Oct,24.2007-20:03
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Re: Scroll text techniques
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earx
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Oct,24.2007-20:09
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Re: Scroll text techniques
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earx
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Oct,24.2007-20:27
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Re: Scroll text techniques
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earx
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Oct,24.2007-20:31
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Re: Scroll text techniques
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earx
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Oct,24.2007-20:32
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Re: Scroll text techniques
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Vincent Riviere
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Oct,24.2007-22:33
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Re: Scroll text techniques
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earx
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Oct,25.2007-09:49
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Re: Scroll text techniques
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ggn
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Oct,25.2007-11:23
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Re: Scroll text techniques
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Bod/STAX
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Oct,25.2007-17:55
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Re: Scroll text techniques
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evil
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Oct,27.2007-17:50
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Re: Scroll text techniques
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earx
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Oct,27.2007-19:01
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Re: Scroll text techniques
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Bod/STAX
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Oct,27.2007-19:18
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Re: Scroll text techniques
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gloky
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Nov,25.2007-13:22
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Re: Scroll text techniques
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Bod/STAX
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Nov,25.2007-21:26
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Re: Scroll text techniques
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gloky
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Dec,10.2007-22:15
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Re: Scroll text techniques
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gloky
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Jan,04.2008-15:10
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What's the anti-troll code?
That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
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