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

[strk]

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.

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;