[vtkusers] Weird Render results with smartpointer in class
David Lonie
david.lonie at kitware.com
Mon Jun 6 10:47:15 EDT 2016
Hi Andy,
Smart pointers shouldn't be causing this sort of issue, and from glancing
at the example code they appear to be used correctly.
Have you set breakpoints in these functions or added debug output to ensure
that the correct functions are being called as-expected? I suspect that
walking through the code with a debugger would shine some light on the
issue.
HTH,
Dave
On Sun, Jun 5, 2016 at 4:47 PM, andyjk <andrewkeeling at hotmail.com> wrote:
> I have a feeling I am using smart pointers wrongly in a class, and it is
> causing weird rendering results. Can anyone help ?
> I am trying to compare the distances between 2 polydatas using different
> techniques. One function measures the vertex to surface distance. The other
> takes lots of samples on the test polydata and measures the distance to the
> surface of the reference polydata. The test and reference polydatas do not
> change, and the numbers (mean distance etc ) given by the functions are
> correct. However, the display deteriorates with use.
>
> I guess I need to know how to completely reset the pipeline in the class,
> ensuring the members are wiped before being reused (polydata, actor, mapper
> and renderer), although I had hoped I could just reset the polydata witha
> DeepCopy, and the pipeline would update.
>
> I have a class and in the header I declare :
> (QTCompare.h)
>
> vtkSmartPointer<vtkPolyDataMapper> resultMapper_;
> vtkSmartPointer<vtkRenderer> resultRenderer_;
> vtkSmartPointer<vtkActor> resultActor_;
>
> vtkSmartPointer<vtkPolyData> resultPolydata_;
>
> vtkSmartPointer<vtkFloatArray> distances_; // The scalar array holding the
> distances
> vtkSmartPointer<vtkScalarBarActor> scalarBar_; // To show the colour scale
>
> (I also declare two more polydatas : TestPolydata and targetPolydata, which
> are read in fine from a file)
>
> When the class is instantiated :
> (QTCompare.cpp)
>
> resultPolydata_ = vtkSmartPointer<vtkPolyData>::New();
> resultMapper_ = vtkSmartPointer<vtkPolyDataMapper>::New();
> resultActor_ = vtkSmartPointer<vtkActor>::New();
> resultMapper_->SetInputData(resultPolydata_);
> resultActor_->SetMapper(resultMapper_);
> resultRenderer_ = vtkSmartPointer<vtkRenderer>::New();
> resultRenderer_->AddActor(resultActor_);
> // VTK/Qt wedded
> this->qvtkWidgetResult->GetRenderWindow()->AddRenderer(resultRenderer_);
>
> // The distances array
> distances_ = vtkSmartPointer<vtkFloatArray>::New();
> scalarBar_ = vtkSmartPointer<vtkScalarBarActor>::New();
>
>
> So far, I have created the pipeline with a blank polydata. Then, when a
> certain button is pressed I do :
>
> void QtCompare::sampleVertices()
> {
>
> txtOutput->append("Sampling vertices...");
>
> vtkIdType nPoints = testPolydata_->GetNumberOfPoints();
> if (nPoints == 0) return;
> distances_->Initialize();
> distances_->SetNumberOfValues(nPoints);
>
> resultPolydata_->DeepCopy(testPolydata_);
>
> // Create the tree
> if (referencePolydata_->GetNumberOfCells() == 0) return;
> vtkSmartPointer<vtkCellLocator> cellLocator =
> vtkSmartPointer<vtkCellLocator>::New();
> cellLocator->SetDataSet(referencePolydata_);
> cellLocator->BuildLocator();
>
>
> txtOutput->append("Number of Samples : " +
> QString::number(nPoints));
>
>
> // Main loop
> for (vtkIdType i = 0; i < nPoints; i++) {
>
> double testPoint[3];
> testPolydata_->GetPoint(i, testPoint);
>
> //Find the closest points to TestPoint
> double closestPoint[3];//the coordinates of the closest point
> will be returned here
> double closestPointDist2; //the squared distance to the
> closest
> point will be returned here
> vtkIdType cellId; //the cell id of the cell containing the
> closest point will be returned here
> int subId; //this is rarely used (in triangle strips only, I
> believe)
> cellLocator->FindClosestPoint(testPoint, closestPoint, cellId,
> subId, closestPointDist2);
>
> double distance = sqrt(closestPointDist2);
>
> distances_->SetValue(i, (float)distance);
>
> }
> cout << "N scalars :" << this->distances_->GetSize() << endl;
> // Add the distances to the result polydata (for colour)
> resultPolydata_->GetPointData()->SetScalars(distances_);
>
> // Get min and max
> double range[2];
> distances_->Modified();
> distances_->GetRange(range);
> txtOutput->append("Range of Samples : " +
> QString::number(range[0],'f',4) + " to " +
> QString::number(range[1],'f',4));
> range[0] = 0.0; range[1] = 0.5;
>
> // Add in the mapper and set up scalar colours
> resultMapper_->ScalarVisibilityOn();
> resultMapper_->SetScalarModeToUsePointData();
> resultMapper_->SetColorModeToMapScalars();
> resultMapper_->SetScalarRange(range[0], range[1]);
> resultMapper_->Modified();
>
> //resultActor_->SetMapper(resultMapper_);
> resultActor_->GetProperty()->SetRepresentationToSurface();
> resultActor_->Modified();
>
>
> scalarBar_->SetTitle("Vertex Distances");
> scalarBar_->SetNumberOfLabels(6);
>
> vtkSmartPointer<vtkLookupTable> hueLUT =
> vtkSmartPointer<vtkLookupTable>::New();
> hueLUT->SetNumberOfTableValues(10);
> hueLUT->SetTableRange(range[0], range[1]);
> hueLUT->SetHueRange(0.625, 0.0);
> hueLUT->SetValueRange(1, 1);
> hueLUT->SetSaturationRange(1, 1);
> hueLUT->Build();
>
> resultMapper_->SetLookupTable(hueLUT);
> scalarBar_->SetLookupTable(hueLUT);
>
> this->resultRenderer_->Clear();
> this->resultRenderer_->AddActor2D(scalarBar_);
> this->resultRenderer_->ResetCamera();
> this->qvtkWidgetResult->GetRenderWindow()->Render();
>
> float sd = standard_deviation(); // Reports mean and SD in the
> output
> window
>
> }
>
> This all works once, but I have another function (almost the same) which
> refills the class members distances_, resultPolydata_, resultMapper_ and
> resultActor_. In this function the pointrepresentation is set to points,
> and
> the polydata has many more points than the original.
>
> This function looks like :
> void QtCompare::uniformSample()
> {
> txtOutput->append("Uniform sampling at 10 microns...");
>
> // Sample points at 0.01mm intervals
> vtkSmartPointer<vtkPolyDataPointSampler> pointSampler =
> vtkSmartPointer<vtkPolyDataPointSampler>::New();
> pointSampler->SetDistance(.01);
> pointSampler->SetInputData(testPolydata_);
> pointSampler->Update();
>
> vtkIdType nPoints = pointSampler->GetOutput()->GetNumberOfPoints();
>
> if (nPoints == 0) return;
> distances_->Initialize();
> distances_->SetNumberOfValues(nPoints);
>
> txtOutput->append("Number of Samples : " +
> QString::number(nPoints));
>
> // Create a polydata made from all the samples
> resultPolydata_->DeepCopy(pointSampler->GetOutput());
>
> // Create the tree
> if (referencePolydata_->GetNumberOfCells() == 0) return;
> vtkSmartPointer<vtkCellLocator> cellLocator =
> vtkSmartPointer<vtkCellLocator>::New();
> cellLocator->SetDataSet(referencePolydata_);
> cellLocator->BuildLocator();
>
> // Main loop
> for (vtkIdType i = 0; i < nPoints; i++) {
>
> double testPoint[3];
> resultPolydata_->GetPoint(i, testPoint);
>
>
> //Find the closest points to TestPoint
> double closestPoint[3];//the coordinates of the closest point
> will be returned here
> double closestPointDist2; //the squared distance to the
> closest
> point will be returned here
> vtkIdType cellId; //the cell id of the cell containing the
> closest point will be returned here
> int subId; //this is rarely used (in triangle strips only, I
> believe)
> cellLocator->FindClosestPoint(testPoint, closestPoint, cellId,
> subId, closestPointDist2);
>
> double distance = sqrt(closestPointDist2);
>
> distances_->SetValue(i, (float)distance);
>
> }
>
> // Add the distances to the result polydata (for colour)
> resultPolydata_->GetPointData()->SetScalars(distances_);
>
> // Get min and max
> double range[2];
> distances_->Modified();
> distances_->GetRange(range);
> txtOutput->append("Range of Samples : " +
> QString::number(range[0],'f',4) + " to " +
> QString::number(range[1],'f',4));
>
> // Add in the mapper and set up scalar colours
> resultMapper_->ScalarVisibilityOn();
> resultMapper_->SetScalarModeToUsePointData();
> resultMapper_->SetColorModeToMapScalars();
> resultMapper_->SetScalarRange(range[0], range[1]);
> resultMapper_->Modified();
>
> resultActor_->SetMapper(resultMapper_);
> resultActor_->Modified();
> resultActor_->GetProperty()->SetRepresentationToPoints();
> resultActor_->Modified();
>
> scalarBar_->SetTitle("Uniform Sampling Distances");
> scalarBar_->SetNumberOfLabels(6);
>
> vtkSmartPointer<vtkLookupTable> hueLUT =
> vtkSmartPointer<vtkLookupTable>::New();
> hueLUT->SetNumberOfTableValues(10);
> hueLUT->SetTableRange(range[0], range[1]);
> hueLUT->SetHueRange(0.3, 0.0);
> hueLUT->SetValueRange(1, 1);
> hueLUT->SetSaturationRange(1, 1);
> hueLUT->Build();
>
> resultMapper_->SetLookupTable(hueLUT);
> scalarBar_->SetLookupTable(hueLUT);
>
> txtOutput->append(QString::number(
> resultActor_->GetReferenceCount()));
>
> this->resultRenderer_->Clear();
> this->resultRenderer_->AddActor2D(scalarBar_);
> this->resultRenderer_->ResetCamera();
> this->qvtkWidgetResult->GetRenderWindow()->Render();
>
>
> float sd = standard_deviation(); // Reports mean and SD in the
> output
> window
>
>
> }
>
>
> This also works fine. Now the strange bit. If I call the first function
> again, everything displays as expected. BUT, if I then call the first
> function again (so nothing should change) the data from the second function
> gets displayed. This toggles every time I call the first function! The
> values given by my ‘standard_deviation()’ function remain correct
> throughout, so the maths is being done on the correct data each time, but
> for some reason the display keeps changing its source data!
>
> Does anyone know what I am doing wrong ?
>
> Thanks
>
>
>
>
>
> --
> View this message in context:
> http://vtk.1045678.n5.nabble.com/Weird-Render-results-with-smartpointer-in-class-tp5738563.html
> Sent from the VTK - Users mailing list archive at Nabble.com.
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