private void VectorFieldNonZeroExtraction()
{
// Create an image
vtkImageData image = vtkImageData.New();
CreateVectorField(ref image);
// This filter produces a vtkImageData with an array named "Magnitude"
vtkImageMagnitude magnitudeFilter = vtkImageMagnitude.New();
magnitudeFilter.SetInputConnection(image.GetProducerPort());
magnitudeFilter.Update();
image.GetPointData().AddArray(magnitudeFilter.GetOutput().GetPointData().GetScalars());
image.GetPointData().SetActiveScalars("Magnitude");
vtkThresholdPoints thresholdVector = vtkThresholdPoints.New();
thresholdVector.SetInput(image);
thresholdVector.SetInputArrayToProcess(
0,
0,
(int)vtkDataObject.FieldAssociations.FIELD_ASSOCIATION_POINTS,
(int)vtkDataSetAttributes.AttributeTypes.SCALARS,
"Magnitude");
thresholdVector.ThresholdByUpper(0.00001);
thresholdVector.Update();
// in case you want to save imageData
//vtkXMLPolyDataWriter writer = vtkXMLPolyDataWriter.New();
//writer.SetFileName("output.vtp");
//writer.SetInputConnection(thresholdPoints.GetOutputPort());
//writer.Write();
// repesents the pixels
vtkCubeSource cubeSource = vtkCubeSource.New();
cubeSource.SetXLength(2.0);
cubeSource.SetYLength(2.0);
cubeSource.SetZLength(2.0);
vtkGlyph3D glyph = vtkGlyph3D.New();
glyph.SetInput(image);
glyph.SetSourceConnection(cubeSource.GetOutputPort());
// don't scale glyphs according to any scalar data
glyph.SetScaleModeToDataScalingOff();
vtkPolyDataMapper glyphMapper = vtkPolyDataMapper.New();
glyphMapper.SetInputConnection(glyph.GetOutputPort());
// don't color glyphs according to scalar data
glyphMapper.ScalarVisibilityOff();
glyphMapper.SetScalarModeToDefault();
vtkActor actor = vtkActor.New();
actor.SetMapper(glyphMapper);
// represent vector field
vtkGlyph3D vectorGlyph = vtkGlyph3D.New();
vtkArrowSource arrowSource = vtkArrowSource.New();
vtkPolyDataMapper vectorGlyphMapper = vtkPolyDataMapper.New();
int n = image.GetPointData().GetNumberOfArrays();
for (int i = 0; i < n; i++)
{
Debug.WriteLine("name of array[" + i + "]: " + image.GetPointData().GetArrayName(i));
}
vtkPolyData tmp = thresholdVector.GetOutput();
Debug.WriteLine("number of thresholded points: " + tmp.GetNumberOfPoints());
vectorGlyph.SetInputConnection(thresholdVector.GetOutputPort());
// in case you want the point glyphs to be oriented according to
// scalar values in array "ImageScalars" uncomment the following line
image.GetPointData().SetActiveVectors("ImageScalars");
vectorGlyph.SetSourceConnection(arrowSource.GetOutputPort());
vectorGlyph.SetScaleModeToScaleByVector();
vectorGlyph.SetVectorModeToUseVector();
vectorGlyph.ScalingOn();
vectorGlyph.OrientOn();
vectorGlyph.SetInputArrayToProcess(
1,
0,
(int)vtkDataObject.FieldAssociations.FIELD_ASSOCIATION_POINTS,
(int)vtkDataSetAttributes.AttributeTypes.SCALARS,
"ImageScalars");
vectorGlyph.Update();
vectorGlyphMapper.SetInputConnection(vectorGlyph.GetOutputPort());
vectorGlyphMapper.Update();
vtkActor vectorActor = vtkActor.New();
vectorActor.SetMapper(vectorGlyphMapper);
// get a reference to the renderwindow of our renderWindowControl1
vtkRenderWindow renderWindow = renderWindowControl1.RenderWindow;
// renderer
vtkRenderer renderer = renderWindow.GetRenderers().GetFirstRenderer();
// set background color
renderer.SetBackground(.2, .6, .3);
//Add the actors to the renderer, set the background and size
renderer.AddActor(actor);
renderer.AddActor(vectorActor);
}
