Idear for OpenGL overdraw child windows Bug

[Stefan Dösinger]

Am Montag 24 Juli 2006 22:01 schrieb Florian Köberle:
> When OpenGL draws, child windows get overdrawn.
>
> The suggestions to solve these problem where all based on the idear of
> clipping that what OpenGL render so that OpenGL doesn't overdraw them.
>
> What do you think of the idear of letting OpenGL overdrawing the child
> windows, but then after this we redraw all the child windows?
>
> There are two things who have to be done:
> 1.) find out when OpenGL finished his drawing
> 2.) find a way to draw the child windows.
>
> possible solutions for 2.)
> The easiest (but slowest) way of doing this could be a broadcast of the
> window message WM_PAINT to all child windows.
It could work, but the performance hit would be quite hard(window redrawing is 
slow), and it still wouldn't sove the placement problem. Furthermore there is 
the problem that opengl is asynchronous, so it might happen that opengl 
drawing is started, you detect that the window needs redrawing, redaw and 
then opengl is finished drawing and draws over the just redrawn window. You 
would have to wait for gl after every gl call which would make it even 
slower. It is highly unlikely to ever occur, but it can happen.

Another issue is that the constant redrawing would cause a lot of flickering 
in the redrawn area which won't look nice.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 191 bytes
Desc: not available
Url : http://www.winehq.org/pipermail/wine-devel/attachments/20060726/04e6798d/attachment.pgp