[vtkusers] VTK 7.0.0.RC1 (and releases before): X-OpenGL depth test(?) problems when using QVTKRenderWindow

[Sophonet]

Hi David,

The problem occurs as well when running QVTKRenderWindowInteractor.py 
directly.

I have tried picking the Mesa software renderer to exclude a graphics 
driver problem by

LIBGL_ALWAYS_SOFTWARE=1 GALLIUM_DRIVER=softpipe python 
PATHTO_/QVTKRenderWindowInteractor.py, but same problem.

The software renderer is chosen by setting the two variables as I could 
verify with

LIBGL_ALWAYS_SOFTWARE=1 GALLIUM_DRIVER=softpipe glxinfo:

...
OpenGL renderer string: Gallium 0.4 on softpipe
OpenGL version string: 2.1 Mesa 9.2.3
OpenGL shading language version string: 1.30
...

I have found a related thread here (8 years old):

http://osdir.com/ml/python-enthought-devel/2008-04/msg00491.html

...but as opposed to the problem described there, I do not see warnings 
on a missing depth buffer when turning on MESA_DEBUG=1 - only the errors 
with respect to glDrawBuffer / glReadBuffer (see my previous e-mail)... 
and in order to rule out device driver problems, I have forced software 
rendering as mentioned above.

I would be happy to debug further if I would know how.

Thanks,

        sophonet


Am 2016-01-14 21:39, schrieb David Gobbi:
> Hi Sophonet,
> 
> QVTKRenderWindowInteractor.py has a "main" and can be run as an
> example.  If you run it, does it show the same problem?
> 
> I recently tried it with VTK 7.0.0.rc1 and didn't see any depth buffer
> issues (using Ubuntu 12.04).
> 
>  - David
> 
> On Thu, Jan 14, 2016 at 1:17 PM, Sophonet
> <vtk12af6bc42 at kant.sophonet.de> wrote:
> 
>> Dear list,
>> 
>> when trying to run a Qt Python application using the
>> qt.QTVTKRenderWindow, there are depth test problems.
>> 
>> Examples/Tutorial/Step1/Python/Cone.py works perfect, but with a
>> simple QVTKRenderWindow example (based on
>> https://gist.github.com/samueljohn/3090097 [1], needs two more
>> imports though), there are depth test problems, i.e. it appears that
>> for some reason no depth test is applied (so the last drawn
>> primitive is always visible on top).
>> 
>> When doing
>> 
>> export MESA_DEBUG=1
>> 
>> before running the two scripts, there is one warning in the
>> Examples/Tutorial/Step1/Python/Cone.py,
>> 
>> Mesa warning: couldn't open libtxc_dxtn.so, software DXTn
>> compression/decompression unavailable
>> 
>> [but everything looks fine],
>> 
>> but many more with the QVTKRenderWindow
>> 
>> Mesa: User error: GL_INVALID_OPERATION in
>> glDrawBuffer(buffer=0x405)
>> Mesa: User error: GL_INVALID_OPERATION in
>> glReadBuffer(buffer=0x405)
>> ...
>> 
>> I am running Mesa 9.2.3 on my system (OpenSUSE 13.1), so I cannot
>> switch to the OpenGL2 rendering backend (which might resolve the
>> problem? - don't know...).
>> 
>> Any hints?
>> 
>> Thanks,
>> 
>>      sophonet
> 
> 
> Links:
> ------
> [1] https://gist.github.com/samueljohn/3090097