| RE: [AD] BUG: Page flipping and the screen |
[ Thread Index |
Date Index
| More lists.liballeg.org/allegro-developers Archives
]
> -----Oorspronkelijk bericht-----
> Van: alleg-developers-admin@xxxxxxxxxx
> [mailto:alleg-developers-admin@xxxxxxxxxx Eric
> Botcazou
> Verzonden: dinsdag 18 februari 2003 18:17
> Aan: alleg-developers@xxxxxxxxxx
> Onderwerp: Re: [AD] BUG: Page flipping and the screen
>
>
> > Are you sure? I thought it always points to the entire virtual screen,
> > at least I'm almost sure that's how it used to be a few of years ago.
> > The old way of page flipping (before the invention of
> > create_video_bitmap()) was to use scroll_screen() and keep track of
> > where to draw on the virtual screen. So if the semantics of screen
> > changes, I think it might break old programs.
>
> I'm obviously a bit Windows-centric: I was only thinking of the platforms
> where the video memory is split into several pages. In this case, drawing
> onto the 'screen' bitmap would do nothing at all if it pointed to the
> backbuffer.
>
> But now, after your remark, it seems pretty clear that the
> feature would not
> be portable to the platforms with one flat surface of video memory so it
> probably doesn't matter after all.
>
> --
> Eric Botcazou
>
>
How about a function that returns the currently visible page?
Or a global BITMAP* that points to it? (like a second screen)
It's really essential we know where to draw to get things on the screen.