[vtkusers] stenciling problem-- is this code thread safe?

[Mark Roden]

wait, never mind!  I had some issues with vtk strings, but it appears
that this line:

outWin.SetInstance(outWin);

is now deprecated or something, because having that line active in this snippet:

            vtkFileOutputWindow outWin = new vtkFileOutputWindow();
            outWin.SetInstance(outWin);
            outWin.SetFileName("MVSVTKViewer.log");

throws this exception:

Exception in thread "main" java.lang.NoSuchFieldError: vtkId
        at vtk.vtkOutputWindow.SetInstance_3(Native Method)
        at vtk.vtkOutputWindow.SetInstance(vtkOutputWindow.java:45)
        at com.mvs.viewer.Application.main(Application.java:63)

But that's a different issue (bug?)

On Fri, Feb 11, 2011 at 10:35 AM, David Gobbi <david.gobbi at gmail.com> wrote:
> If you are reporting the vtkLinearExtrusionFilter, I already did.
>
> On Fri, Feb 11, 2011 at 11:31 AM, Mark Roden <mmroden at gmail.com> wrote:
>> Hi David,
>>
>> Unfortunately,  the current vtk master branch is seriously broken in
>> its java wrappings.  I'm putting together a bug report now...
>>
>> Thanks,
>> Mark
>>
>> On Fri, Feb 11, 2011 at 10:09 AM, David Gobbi <david.gobbi at gmail.com> wrote:
>>> I should add: with the current VTK master and release branches,
>>> vtkPolyDataToImageStencil no longer requires vtkLinearExtrusionFilter
>>> to be used beforehand.  So you could try that.
>>>
>>>  - David
>>>
>>>
>>> On Fri, Feb 11, 2011 at 11:06 AM, David Gobbi <david.gobbi at gmail.com> wrote:
>>>> I was doubtful about the global memory, but I looked through the
>>>> filters just to be sure.  And guess what I found... here is some
>>>> highly suspect code in vtkLinearExtrusionFilter:
>>>>
>>>> double *vtkLinearExtrusionFilter::ViaNormal(double x[3], vtkIdType id,
>>>>                                           vtkDataArray *n)
>>>> {
>>>>  static double xNew[3], normal[3];
>>>>  int i;
>>>>
>>>>  n->GetTuple(id, normal);
>>>>  for (i=0; i<3; i++)
>>>>    {
>>>>    xNew[i] = x[i] + this->ScaleFactor*normal[i];
>>>>    }
>>>>
>>>>  return xNew;
>>>> }
>>>>
>>>> Code like the above is definitely going to cause thread problems.
>>>> And this isn't the only place in that class where code like this appears.
>>>>
>>>> Yikes!
>>>>
>>>>  - David
>>>>
>>>>
>>>> On Fri, Feb 11, 2011 at 10:46 AM, Mark Roden <mmroden at gmail.com> wrote:
>>>>> What I mean is, I have a vtkPolyData that has been DeepCopied and a
>>>>> vtkImageData that is binary and distinct from all other data.
>>>>>
>>>>> When I call the previously listed code with multiple threads (each
>>>>> with their own polydata and binary image to fill in), the result is
>>>>> generally a very garbled image.  If I call from a single thread in
>>>>> series, one for each polydata/image pair, then everything works out
>>>>> fine.
>>>>>
>>>>> So it seems to me that something in the above series isn't thread
>>>>> safe.  Each thread is declaring its own local objects, but is there
>>>>> some global memory that's being used or accessed here?
>>>>>
>>>>> On Fri, Feb 11, 2011 at 9:23 AM, David Gobbi <david.gobbi at gmail.com> wrote:
>>>>>> Hi Mark,
>>>>>>
>>>>>> Explain in more detail what you mean by "call from multiple threads".
>>>>>> VTK is, in general, not thread safe and you cannot call Update() on
>>>>>> a filter from more than one thread.  Each thread needs to have its own
>>>>>> set of filters.  And in general, you cannot feed a data object into more
>>>>>> than one thread, because even simple methods like GetBounds() are
>>>>>> not thread safe.
>>>>>>
>>>>>> When using VTK from multiple threads, it is necessary to apply
>>>>>> extreme caution.
>>>>>>
>>>>>>  - David
>>>>>>
>>>>>>
>>>>>> On Fri, Feb 11, 2011 at 10:00 AM, Mark Roden <mmroden at gmail.com> wrote:
>>>>>>> Hi all,
>>>>>>>
>>>>>>> This code does not have threads enabled in vtk 5.6.1 (the code is in Java):
>>>>>>>
>>>>>>>        vtkLinearExtrusionFilter extruder = new vtkLinearExtrusionFilter();
>>>>>>>        extruder.SetInput(data);
>>>>>>>        extruder.SetVector(0, 0, spacing[2]);
>>>>>>>        extruder.Update();
>>>>>>>        vtkPolyData extruderOutput = extruder.GetOutput();
>>>>>>>
>>>>>>>        vtkPolyDataToImageStencil pol2Stenc = new vtkPolyDataToImageStencil();
>>>>>>>        pol2Stenc.SetTolerance(0);
>>>>>>>        pol2Stenc.SetInput(extruderOutput);
>>>>>>>        pol2Stenc.SetInformationInput(binaryOrgan);
>>>>>>>        pol2Stenc.Update();
>>>>>>>        vtkImageStencilData pol2StencOutput = pol2Stenc.GetOutput();
>>>>>>>
>>>>>>>        // This is where the memory leak is!!!!
>>>>>>>        vtkImageStencil stencil = new vtkImageStencil();
>>>>>>>        stencil.SetInput(binaryOrgan);
>>>>>>>        stencil.ReverseStencilOn();
>>>>>>>        stencil.SetStencil(pol2StencOutput);
>>>>>>>        stencil.Update();
>>>>>>>
>>>>>>>        // We're doing this because of an email to Mark
>>>>>>>        // that says this will fix our memory issues
>>>>>>>        final vtkImageData stencilOutput = stencil.GetOutput();
>>>>>>>        final vtkImageData imageToKeep = new vtkImageData();
>>>>>>>        imageToKeep.DeepCopy(stencilOutput);
>>>>>>>        stencilOutput.Delete();
>>>>>>>
>>>>>>> When I try to call this code from multiple threads (ie, to create the
>>>>>>> stencils for multiple organs), Bad Things happen, as in, the data are
>>>>>>> entirely corrupted.  Is this code thread safe?
>>>>>>>
>>>>>>> Mark
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>>>>>>
>>>>>
>>>>
>>>
>>
>