On Sat Sep 16 21:02:34 2000, dennis@xxxxxxxxxxxxxxxxxxxxxx wrote:
>
> Hi Jonathan,
>
> Thanks for the explanation of why NULL can't be passed as the name
> parameter to an XmCreate* routine with Motif 2.1.
I didn't go through the Motif 2.1 source in too much detail, but I believe only
XmCreatePulldownMenu() has that problem; the other functions pass along their
arguments to XtCreateWidget(). I only changed those files that had calls to
XmCreatePulldownMenu().
> Finally, I found the cause of the problem with the sliders, color wheel
> and color patches used by the Material Editor. When compiled against
> openmotif-2.1.30-4_MLI from Metrolink, on a generic PC with RH 6.2, the
> devices get drawn using double buffering. After adding calls to
> glXSwapBuffers as detailed below, ALL of the Editors work perfectly. :-)
> I changed the source as follows:
The problem here is that glXChooseVisual() isn't working as it should on your
system (and mine, with Mesa). Note that the sliders do not specify a
SO_GLX_DOUBLE attribute when requesting a visual to associate their GLw drawing
area with in SoXtGLWidget::buildNormalGLXWidget(). For whatever reason, a
doublebuffer visual is returned anyway.
> I don't know what the best way to fix this in the common source tree
> would be. Perhaps some conditional compilation option is currently not
> working as intended with the combination of libraries that I am using.
To work around the bug, I'm including some code to determine if a doublebuffer
visual is returned, and setting the SO_GLX_DOUBLE bit in glModes accordingly.
In the slider source files, I call isDoubleBuffer() to determine whether to
call glXSwapBuffers() or glFlush().
> By the way, thanks a lot for the excellent work that you and your
> colleagues have done with Open Inventor, and thanks to SGI for making
> it available under the GNU Lesser GPL. We will be using it this semester
> in our computer graphics course.
No problem. Thanks for your help identifying the bug above.
> Regards,
> Dennis
>
> --
> Dennis Mikkelson
> dennis@xxxxxxxxxxxxxxxxxxxxxx
Jonathan Lim _ Silicon Graphics _ Mountain View
GPS Graphics Computer Systems CA, USA
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