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

[Quinn Storm]

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

>
> We have two sets of invalidated bounds in gnash: one is the bound of
> invalidated regions due to playback, another is the bound of invalidated
> regions due to expose events. The renderer would render in the off-screen
> buffer only the playback-invalidated bounds, and from pixmap to on-screen
> only the expose-invalidated bounds would be copied.
>
> Does it sound ?
>
> --strk;