[SDL] Double buffering in windowed and fullscreen modes

Rainer Deyke root at rainerdeyke.com
Fri Aug 31 12:11:00 PDT 2001

"David Olofson" <david.olofson at reologica.se> wrote in message
news:mailman.999276066.6350.sdl at libsdl.org...
> On Friday 31 August 2001 17:28, Tyler Montbriand wrote:
> > Pete Shinners wrote:
> > > i'm guessing you're running windows? in any event SDL doesn't
> > > do hardware surfaces for windowed displays. :[
> > > what resolution are you running at?
> >
> > No hardware acceleration for windowed surfaces?  Will this be fixed in
> > SDL1.3?
> AFAIK, no. Windows doesn't support it - and cannot, without hardware
> based clipping. DirectX allows you to blit to the "screen" surface of a
> window and does clipping internally, but if you were allowed to lock the
> surface and access VRAM directly, you'd have to deal with clipping
> yourself not to overdraw other windows, mouse pointer (unless it's a
> hardware sprite), menues etc.

This should not really be a problem.  Just create a virtual screen surface
in video memory (similar to what 'SDL_DOUBLEBUF' and 'SDL_SWSURFACE' already
do), and do the clipping in 'SDL_Flip' or 'SDL_UpdateRect'.

Rainer Deyke (root at rainerdeyke.com)
Shareware computer games           -           http://rainerdeyke.com
"In ihren Reihen zu stehen heisst unter Feinden zu kaempfen" - Abigor

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