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Atari demoscene BBS
| Re: How do you zoom on Atari? |
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Posted by: evil
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Jan,29.2013-16:44
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"How do you zoom on Atari?"
I can't tell for Overlanders, they probably use a lot of character precalcs (wild guess).
However our fullscreen zoom in Summer Delights is easier to explain of obvious reasons :) It's a 200x7 (or something like this) chunky buffer that is real-time zoomed in X and c2p'd to screen where the video address counter will do the Y-stretch. Unfortunately we ran out of time to complete the effect so the precision of the Y-zoom is really not good enough. Perhaps the zoomscroll will get an improved revenge in a later prod :)
See video at 3:45 : http://dhs.nu/video.php?ID=368
This method can also be applied on ST (ours is STe) in a smaller size, but instead of hardware-stretch, need to copy the data to more lines. One problem appears then, garbage data when the zoom goes backwards (getting smaller). Clearing this garbage is an obvious solution, but much faster to set the palette black around the current zoom-size.
We also did a zoomscroll that goes upwards. It's much less CPU-hungry on STe. The X-stretch is made from different width of graphics stripes (15 colour-stripes), then applying rasters to the stripes so they form letters. Y-stretch is about stretching the raster colours. I guess over half the CPU is left empty in that screen.
See video at 4:50 : http://dhs.nu/video.php?ID=47
--
Anders Eriksson
ae@dhs.nu
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Topic
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Posted by
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Date
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How do you zoom on Atari?
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Zamuel_a
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Jan,28.2013-23:30
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Re: How do you zoom on Atari?
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evil
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Jan,29.2013-16:44
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Re: How do you zoom on Atari?
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Zamuel_a
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Jan,29.2013-17:16
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Re: How do you zoom on Atari?
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evil
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Jan,29.2013-17:34
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Re: How do you zoom on Atari?
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Paranoid / pdx
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Jan,29.2013-22:39
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Re: How do you zoom on Atari?
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Bod/STAX
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Jan,29.2013-17:21
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Re: How do you zoom on Atari?
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Zamuel_a
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Jan,29.2013-19:36
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Re: How do you zoom on Atari?
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ggn
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Jan,30.2013-09:47
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Re: How do you zoom on Atari?
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Zamuel_a
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Jan,30.2013-12:30
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Re: How do you zoom on Atari?
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nativ
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Jan,31.2013-16:21
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Re: How do you zoom on Atari?
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Dma-Sc
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Feb,01.2013-12:39
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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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