Re: A89: Re: HW vertical scrolling...
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Re: A89: Re: HW vertical scrolling...
On Wed, Apr 12, 2000 at 06:41:10PM +0200, Niklas Brunlid wrote:
>
> To do a game you'd need to have something actually moving around on the screen
> and that's usually done with a double-buffer technique, which obviously wouldn't
> work with this hardware scrolling... the alternative is keeping track of
> everything that's plotted on the hardware-scrolling data, and copies of that
> which you've plotted over so you can restore it when needed. In any case it
> would probably flicker a lot (could probably be fixed with careful timing
> though).
>
> / Niklas Brunlid
> Check out Prosit for the TI-89 / TI-92+ at http://prosit.ticalc.org
> Random PQF Quote follows:
>
Yes, I know that... But that's the way people did it on the PC using mode-x.
But hey, we _CAN_ use double buffering. Just 4 pages... As 8 bytes is quite
flexible. Of course sprites must be utilized, but then one wouldn't need to
redraw the whole background (for example). Or for text-scrollers or
anything. I can't believe it wouldn't have use. AND even 4 shades of gray
could be done using that scrolling. Although memory consuption would then
rise quite high.
And then flickering... I don't think that could be such a problem. Grayscale
is possible, and there you must keep the pages visible for _longer_ time
than absolutely neccessary for just scrolling.
But... your mileage may vary.
Henri Moilanen
Oh, then... What way people usually do that double-buffering? Do they use
that old trick of copying the complete screen, or do they use hardware flip
using that "video mem" start control register?
References: