[vtkusers] Output extent gets lost in custom image algorithm

[Maarten Beek]

Hi all,


I am trying to create a new vtk algorithm.
Inside this algorithm is a small rendering pipeline.

I create the output in RequestDataObject(), set the update extent and allocate memory, but the extent seems to be lost in RequestData().
RequestData() works fine when I set the extent in this function, which means that the memory allocated in RequestDataObject() is still allocated.

So I am wondering where (and why?) the extent is re-set to (0, -1, 0, -1, 0, -1)?

Thanks - Maarten


code:

int X::RequestDataObject()
{
  vtkInformation* info = outVector->GetInformationObject(0);
  vtkImageData* output = vtkImageData::safeDownCast(info->Get(vtkDataObject::DATA_OBJECT()));

  if(!output)
  {
    output = vtkImageData::New();
    info->Set(vtkDataObject::DATA_OBJECT(), output);
    output->Delete();

  }

  if( check to determine whether update extent needs updating )
  {
    info->Set(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(), extent, 6);
    AllocateOutputData(info->Get(vtkDataObject::DATA_OBJECT()), info); // sets extent for vtkImageData object

  }

}


int X::RequestData()
{
  vtkInformation* info = outVector->GetInformationObject(0);
  vtkImageData* output = vtkImageData::safeDownCast(info->Get(vtkDataObject::DATA_OBJECT()));

  this->InternalRenderWindow->Render();
  this->InternalRenderWindow->WaitForCompletion();

  int size[2];
  size[0] = this->InternalRenderWindow->GetSize()[0];
  size[1] = this->InternalRenderWindow->GetSize()[1];

  // hack required

  {

    int extent[6];
    info->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(), extent);
    output->SetExtent(extent);
  }


  vtkFloatArray* data = vtkFloatArray::SafeDownCast(output->GetPointData()->GetScalars());
  this->InternalRenderWindow->GetRBGAPixelData(0, 0, size[0]-1, size[1]-1, 1, data);
}
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