[Xquartz-dev] 2.3.3_rc1

George Peter Staplin georgeps at xmission.com
Tue Mar 10 12:58:39 PDT 2009


Quoted Jeremy Huddleston <jeremyhu at apple.com>:

>
> On Mar 10, 2009, at 12:31, Jeremy Huddleston wrote:
>
>> BTW, one more point I just want to clarify.  Are you certain that   
>> the version of vmd-xplor on all machines is identical and that they  
>>  are all linking against the libGL in /usr/X11/lib/libGL.dylib?
>>
>> You're good about that sort of thing, but I just wanted to be   
>> explicit since it might be possible to link against a Mesa libGL if  
>>  it was built with MacPorts or Fink or some other package system.
>>
>> Also, as for dropping down to software rendering goes, I added   
>> support for two environment variables: LIBGL_ALWAYS_HARDWARE and   
>> LIBGL_ALWAYS_SOFTWARE.  See   
>> http://xquartz.macosforge.org/trac/changeset/304
>
> Now that I look at this some more, I think there are still some bits
> missing.  The GLcontextMode that we're passed in
> apple_visual_create_pfobj may actually be a SW-only mode, and by
> forcing kCGLPFAAccelerated, kCGLPFAClosestPolicy in the attribs, we're
> not going to get the actual mode requested but a similar fit.  We
> probably need to add some bits to filter the visuals and fbconfigs
> based on LIBGL_ALWAYS_SOFTWARE as well.

The software visuals should be marked with "Slow" in glxinfo -v.  It  
comes from this:

if(conf->accelerated) {
     visualConfigs[i].visualRating = GLX_NONE;
} else {
     visualConfigs[i].visualRating = GLX_SLOW_VISUAL_EXT;
}

That code is from:  
http://cgit.freedesktop.org/xorg/xserver/tree/hw/xquartz/GL/visualConfigs.c?h=xorg-server-1.4-apple

> But the lib that I sent you should still work at forcing HW or SW...
> you will just get a "close" rather than "exact" match for the visual.

Perhaps we could make the ALWAYS env knobs consider the visual rating.  
  We should probably also make the pixel format creator return a  
boolean to indicate success or failure then, because we may have a  
more likely failure to create a valid CGLPixelFormatObj in those cases  
(especially with the forced accelerated).  The visualConfigs.c code  
takes the attributes from the capabilities.c code I wrote that probes  
the CGL framework and displays for valid attributes.

George
-- 
http://people.freedesktop.org/~gstaplin/


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