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# TextureThreshold

VTKEx/Python/Texture/TextureThreshold

### Description

Demonstrating texture thresholding applied to scalar data from a simulation of fluid flow.

There are three planes cutting the blunt fin with different thresholds set. From the left, the scalar threshold is set so that:

1) Only data with a scalar value greater than or equal to 1.5 is shown. 2) Only data with a scalar value less than or equal to 1.5 is shown. 3) Only data with a scalar value between 1.5 and 1.8 inclusive is shown.

Other languages

See (Cxx)

Question

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### Code

TextureThreshold.py

    #!/usr/bin/env python

    # Modified from VTK/Filters/Texture/Testing/Python/textureThreshold.py.

    import vtk

    def main():
        dataFn1, dataFn2, textureFn = get_program_parameters()
        colors = vtk.vtkNamedColors()

        # Read the data.
        pl3d = vtk.vtkMultiBlockPLOT3DReader()
        pl3d.SetXYZFileName(dataFn1)
        pl3d.SetQFileName(dataFn2)
        pl3d.SetScalarFunctionNumber(100)
        pl3d.SetVectorFunctionNumber(202)
        pl3d.Update()
        output = pl3d.GetOutput().GetBlock(0)

        # Make the wall (floor).
        wall = vtk.vtkStructuredGridGeometryFilter()
        wall.SetInputData(output)
        wall.SetExtent(0, 100, 0, 0, 0, 100)
        wallMap = vtk.vtkPolyDataMapper()
        wallMap.SetInputConnection(wall.GetOutputPort())
        wallMap.ScalarVisibilityOff()
        wallActor = vtk.vtkActor()
        wallActor.SetMapper(wallMap)
        wallActor.GetProperty().SetColor(colors.GetColor3d("PeachPuff"))

        # Make the fin (rear wall)
        fin = vtk.vtkStructuredGridGeometryFilter()
        fin.SetInputData(output)
        fin.SetExtent(0, 100, 0, 100, 0, 0)
        finMap = vtk.vtkPolyDataMapper()
        finMap.SetInputConnection(fin.GetOutputPort())
        finMap.ScalarVisibilityOff()
        finActor = vtk.vtkActor()
        finActor.SetMapper(finMap)
        finActor.GetProperty().SetColor(colors.GetColor3d("DarkSlateGray"))

        # Get the texture.
        tmap = vtk.vtkStructuredPointsReader()
        tmap.SetFileName(textureFn)
        texture = vtk.vtkTexture()
        texture.SetInputConnection(tmap.GetOutputPort())
        texture.InterpolateOff()
        texture.RepeatOff()

        # Create the rendering window, renderer, and interactive renderer.
        ren = vtk.vtkRenderer()
        renWin = vtk.vtkRenderWindow()
        renWin.AddRenderer(ren)
        iren = vtk.vtkRenderWindowInteractor()
        iren.SetRenderWindow(renWin)

        # Make the planes to threshold and texture.
        plane = list()
        thresh = list()
        planeMap = list()
        planeActor = list()
        # Define the extents of planes that we will use.
        planeExtents = [[10, 10, 0, 100, 0, 100],
                        [30, 30, 0, 100, 0, 100],
                        [35, 35, 0, 100, 0, 100]]
        # Now set up the pipeline.
        for i in range(0, len(planeExtents)):
            plane.append(vtk.vtkStructuredGridGeometryFilter())
            plane[i].SetInputData(output)
            plane[i].SetExtent(*planeExtents[i])
            thresh.append(vtk.vtkThresholdTextureCoords())
            thresh[i].SetInputConnection(plane[i].GetOutputPort())
            thresh[i].SetInputConnection(plane[i].GetOutputPort())
            # If you want an image similar to Fig 9-43(a) in the VTK textbook,
            # set thresh[i].ThresholdByUpper(1.5) for all planes.
            if i == 1:
                thresh[i].ThresholdByLower(1.5)
            elif i == 2:
                thresh[i].ThresholdBetween(1.5, 1.8)
            else:
                thresh[i].ThresholdByUpper(1.5)
            planeMap.append(vtk.vtkDataSetMapper())
            planeMap[i].SetInputConnection(thresh[i].GetOutputPort())
            planeMap[i].SetScalarRange(output.GetScalarRange())
            planeActor.append(vtk.vtkActor())
            planeActor[i].SetMapper(planeMap[i])
            planeActor[i].SetTexture(texture)
            #  The slight transparency gives a nice effect.
            planeActor[i].GetProperty().SetOpacity(0.999)
            ren.AddActor(planeActor[i])

        # Get an outline of the data set for context.
        outline = vtk.vtkStructuredGridOutlineFilter()
        outline.SetInputData(output)
        outlineMapper = vtk.vtkPolyDataMapper()
        outlineMapper.SetInputConnection(outline.GetOutputPort())
        outlineActor = vtk.vtkActor()
        outlineActor.SetMapper(outlineMapper)
        outlineProp = outlineActor.GetProperty()
        outlineProp.SetColor(colors.GetColor3d("Black"))

        # Add the remaining actors to the renderer, set the background and size.
        ren.AddActor(outlineActor)
        ren.AddActor(wallActor)
        ren.AddActor(finActor)
        ren.SetBackground(colors.GetColor3d("MistyRose"))
        renWin.SetSize(512, 512)
        cam = vtk.vtkCamera()
        cam.SetClippingRange(1.51176, 75.5879)
        cam.SetFocalPoint(2.33749, 2.96739, 3.61023)
        cam.SetPosition(10.8787, 5.27346, 15.8687)
        cam.SetViewAngle(30)
        cam.SetViewUp(-0.0610856, 0.987798, -0.143262)
        ren.SetActiveCamera(cam)

        iren.Initialize()
        iren.Start()

    def get_program_parameters():
        import argparse
        description = 'Demonstrating texture thresholding applied to scalar data from a simulation of fluid flow.'
        epilogue = '''
        There are three planes cutting the blunt fin with different thresholds set.
         From the left, the scalar threshold is set so that:
           1) Only data with a scalar value greater than or equal to 1.5 is shown.
           2) Only data with a scalar value less than or equal to 1.5 is shown.
           3) Only data with a scalar value between 1.5 and 1.8 inclusive is shown.
       '''
        parser = argparse.ArgumentParser(description=description, epilog=epilogue,
                                         formatter_class=argparse.RawDescriptionHelpFormatter)
        parser.add_argument('dataFn1', help='bluntfinxyz.bin.')
        parser.add_argument('dataFn2', help='bluntfinq.bin.')
        parser.add_argument('textureFn', help='texThres2.vtk.')
        args = parser.parse_args()
        return args.dataFn1, args.dataFn2, args.textureFn

    if __name__ == '__main__':
        main()