TextureThreshold

VTKExamples/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.

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()