[Xcb] Double buffering ...

Lars Segerlund lars.segerlund at gmail.com
Thu Aug 5 01:30:37 PDT 2010

 Thanks, you already helped me, I had another look yesterday and it
turns out it's actually MIT-Shm that barfs ....

 And the compilation problems are related to Xproto.h and dbeproto.h ,
there seem's to have been an X11 reorganisation which I was aware of
but still didn't account for.

 I am aiming to rewrite the software to use xcb however, and I have
the simple question to the list if there is support for this, and if
not  what is the preffered method for using double buffering with xcb

 Also any pointers to example, file or any reference material would be
much appreciated, I had a bit of a hard time yesterday trying to
update my build system ... it seems a lot has changed in X.

 / regards, Lars Segerlund.

2010/8/3 Josh Triplett <josh at joshtriplett.org>:
> 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

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