[Xorg] XComposite, XDamage Extension with Xvideo or GL

Alan Cox alan at lxorguk.ukuu.org.uk
Sat Aug 7 08:43:52 PDT 2004

On Sad, 2004-08-07 at 17:07, Amir Bukhari wrote:
> Is there a common Interface in X Server act as communication between X and
> GLX and Graphic Card, which all GLX implementations use it.


When you are doing client side rendering ("direct render") the X server
and 3D clients share a lock and some administrative and security code in
kernel space.

The X server describes the window positions, clipping, layout and other
information the card needs in a shared memory area that the clients can

The normal behaviour (backbuffer using) is that the client renders into
an offscreen pixmap owned by the client and then uses the 2D engine
directly (or via kernel space if insecure in hardware) to blit the
pixels to the front buffer rectangles that are exposed. 

In certain cases programs choose to render to the front buffer and in
that situation the 3D rendering uses the lis of rectangles and draws
directly into it.

More information about the xorg mailing list