Glucose status/instructions request, (and notes on stale branches)

David Reveman davidr at
Tue Nov 6 08:23:39 PST 2007

On Wed, 2007-10-24 at 14:21 -0700, Carl Worth wrote: 
> On Wed, 24 Oct 2007 16:17:28 -0400, David Reveman wrote:
> > glitz_drawable_get_features should give you the list of GL features that
> > glitz has detected and care about.
> Thanks. I do notice that glucose is printing that into the log, but
> not in a way that tells me anything:
> 	(II) intel(0): GLucose reports GLitz features as 0xf7df
> >                                    GL_EXT_fbo is of course required for
> > any accelerated offscreen drawing so you'll need that for any
> > interesting apps to be accelerated.
> Running "glxinfo | grep fbo" shows that I'm missing this on the i965,
> (which is what I expected from recent discussion).

should be something like "glxinfo | grep framebuffer_object" as the full
name of the extension is GLX_EXT_framebuffer_object.

> >                                     the xgl architecture also got some
> > higher level controls for acceleration, e.g. allow acceleration if
> > pixmap has been used for GLX requests, allow acceleration if pixmap has
> > been used for XVideo requests, allow acceleration if pixmap dimensions
> > are larger than a specified value... i'm not sure what glucose sets
> > these controls to but they must also be set appropriately for any
> > acceleration to take place.
> What controls are they if I wanted to poke around in the code?
> > it might be worth printing some of these values at startup so the user
> > can tell what's accelerated and not.
> Yes, anything that helps the user make sense of things would be
> helpful. So far all I did was poke around in gdb a bit to see that
> xglPrepareTarget is causing fallbacks by returning FALSE since
> pPixmapPriv->target == xglPixmapTargetNo. But it wasn't immediately
> obvious what would have to be changed for that to be different.

The accel field in the xglScreenInfo variable which is used to pass
options to the xgl screen initialization code specifies which pixmaps
should be accelerated and not. It's up to the layer above xgl to set the
fields in this structure appropriately. E.g. xglx allows them to be set
using command line options and glucose could of course expose them
through xorg.conf, if we would want that. I haven't looked at the
glucose code lately but I'm guessing that the accel field is hard-coded
right now..


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