[SDL] Re: Fast Scrolling

Marco Salvi nao at libero.it
Mon Aug 16 11:16:07 PDT 1999


Hello Sam

On 15-Ago-99, you wrote:

> The real way to implement a scroller is to adjust the display aperture
> (portion of video memory which is being displayed) dynamically.

That's the way I do vertical scrollers on my old amiga :)
(I have to change some pointers and it's done)

>  It's
> a more fine-grained application of the process which allows double
> buffering.

yeah.


> 
> Unfortunately, with modern video cards, the only API that I know of
> that supports this is X11 DGA.  When in a window, you have to implement
> scrolling with a full-window copy.


Damn :(
I tried to figure out how to adjust screen pointers in SDL..and in fact
I failed :)


>  DirectX only supports page flipping.

I saw several games performs fast (even parallax) scrolling in windows
using dx5.
So...do they  update entire screen all the  times?

> 
> If someone knows better, please let me know!


mee to :)

ciao,
Marco




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