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

[David Gobbi]

Hi Sophonet,

You can try using the vtkRenderWindow to get info from the context, to see
if it's different with QVTKRenderWindowInteractor than without.

There are two boolean methods for vtkRenderWindow:
   window.SupportsOpenGL()
   window.IsDirect()

And also this method that prints a bunch of info:
   print window.ReportCapabilities()

You might have to all Render() once before calling these methods.

 - David


On Fri, Jan 15, 2016 at 2:55 AM, Sophonet <vtk12af6bc42 at kant.sophonet.de>
wrote:

> 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
>>
>
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