[Xorg] XComposite, XDamage Extension with Xvideo or GL

Amir Bukhari ufz6 at rz.uni-karlsruhe.de
Sat Aug 7 12:29:17 PDT 2004

> -----Original Message-----
> From: Alan Cox [mailto:alan at lxorguk.ukuu.org.uk]
> Sent: Saturday, August 07, 2004 7:10 PM
> To: Amir Bukhari
> Cc: xorg at freedesktop.org
> Subject: RE: [Xorg] XComposite, XDamage Extension with Xvideo or GL
> On Sad, 2004-08-07 at 18:59, Amir Bukhari wrote:
> > What confuse me is the end (2D) image (after doing all 3D rendering)
> must be
> > draw to the OpenGL Window. This surely the job of X Server DDX Layer -
> For performance reasons the OpenGL direct render layer does the 2D blit
> itself while holding the X lock so that its window rectangle lists don't
> change under it. What you say is correct for a server side GL
> implementation.
> The DRI client really doesn't care whether its drawing to the window or
> offscreen. The problems is the memory allocation, the mechanism for
> indicating that such behaviour should begin/end and the way in which the
> server finds out if the area has been damaged. (Especially as for
> most games the answer will always be "yes").

It is simple to get Composite to Work with GLX& DRI Server implementation,
because DRI wrap some screen operation. I think it use it to Copy the front
buffer to original Window in X. 
I don't know if Graphics Vendor use Server DRI Extension implementation or
their own implementation.

More information about the xorg mailing list