[Xcb] Double buffering ...

[Josh Triplett]

On Tue, Aug 03, 2010 at 09:30:50AM +0200, Lars Segerlund wrote:
>  I am just qurious , I have some programs using double buffering, and
> they all seem to have stopped working in later X11 releases .. is the
> double buffer support broken ?
> 
>  Double buffering is the only way I have found to do smooth updates on
> old ISA hardware .... which I have in some systems.
> 
>  Any idea on an alternative path to double buffering ? If it's going
> deprecated I would like to rewrite in a compliant manner.

You probably want to ask this question on the xorg mailing list.  Unless
the programs in question attempt to use the XCB library for
double-buffering. :)

To partially answer your question, though: in general, to do smooth
updates, you want to sync with vertical retrace ("vsync").  Double
buffering provides one way to do that: save updates in a back buffer,
then swap the buffers at vsync.  Other mechanisms exist, though they
usually amount to the same general concept.  To know why your programs
stopped working, we'd need to know exactly *how* they try to do
double-buffering.

- Josh Triplett