Re: [Gnash-dev] First stab at fixing an OpenGL bug

[strk]

On Sun, Jun 03, 2007 at 03:06:04AM -0400, Quinn Storm wrote:
> On Sunday 03 June 2007 02:59:38 strk wrote:
> > On Thu, May 31, 2007 at 06:41:18PM -0400, Quinn Storm wrote:
> > ..
> >
> > > the trouble I'm running into with the bug I was trying to tackle is
> > > pretty simple.  OpenGL expects an essentially volatile rendering pattern,
> > > with only transient framebuffers, while gnash expects to render to a
> > > semi-permanent framebuffer that will stick around until changed...and
> > > short of doing a back-to-front copy every time anything is submitted to
> > > render (any line or trimesh), I can't find a way to solve this
> >
> > A solution would be for OpenGL backend to draw into an offscreen buffer
> > and copy that to screen. Depending on GUI it could be done in different
> > ways. For X-based guis, we might use a pixmap. X also has a "backing store"
> > capability, but is not ensured to work. Anyway using a pixmap still has the
> > advantage of more control over what's copied.
> 
> Well unfortunately I have to shoot this idea down right here, as at least on 
> the free driver cards, there is no acceleration at all for the copy that 
> takes place in this situation so it ends up being miserably slow anyhow

What about drawing *both* onscreen and off-screen, so that the copy only occurs 
on expose events ?

--strk;