ENH:Example shows how to use texture thresholding on scalar data

Examples/VisualizationAlgorithms/Tcl/TextureThreshold.tcl

+# Load libraries for VTK
+package require vtk
+package require vtkinteraction
+package require vtktesting
+
+# This example shows how to use a transparent texture map to perform
+# thresholding. The key is the vtkThresholdTextureCoords filter which
+# creates texture coordinates based on a threshold value. These texture
+# coordinates are used in conjuntion with a texture map with varying
+# opacity and intensity to create an inside, transition, and outside
+# region.
+#
+
+# Begin by reading some structure grid data.
+vtkPLOT3DReader pl3d
+    pl3d SetXYZFileName "$VTK_DATA_ROOT/Data/bluntfinxyz.bin"
+    pl3d SetQFileName "$VTK_DATA_ROOT/Data/bluntfinq.bin"
+    pl3d SetScalarFunctionNumber 100
+    pl3d SetVectorFunctionNumber 202
+    pl3d Update
+
+# Now extract surfaces from the grid corresponding to boundary geometry.
+# First the wall.
+vtkStructuredGridGeometryFilter wall
+    wall SetInput [pl3d GetOutput]
+    wall SetExtent 0 100 0 0 0 100
+vtkPolyDataMapper wallMap
+    wallMap SetInput [wall GetOutput]
+    wallMap ScalarVisibilityOff
+vtkActor wallActor
+    wallActor SetMapper wallMap
+    eval [wallActor GetProperty] SetColor 0.8 0.8 0.8
+
+# Now the fin.
+# 
+vtkStructuredGridGeometryFilter fin
+    fin SetInput [pl3d GetOutput]
+    fin SetExtent 0 100 0 100 0 0
+vtkPolyDataMapper finMap
+    finMap SetInput [fin GetOutput]
+    finMap ScalarVisibilityOff
+vtkActor finActor
+    finActor SetMapper finMap
+    eval [finActor GetProperty] SetColor 0.8 0.8 0.8
+
+# Extract planes to threshold. Start by reading the specially
+# designed texture map that has three regions: an inside, boundary,
+# and outside region. The opacity and intensity of this texture map
+# are varied.
+vtkStructuredPointsReader tmap
+  tmap SetFileName "$VTK_DATA_ROOT/Data/texThres2.vtk"
+vtkTexture texture
+  texture SetInput [tmap GetOutput]
+  texture InterpolateOff
+  texture RepeatOff
+
+# Here are the three planes which will be texture thresholded.
+#
+vtkStructuredGridGeometryFilter plane1
+    plane1 SetInput [pl3d GetOutput]
+    plane1 SetExtent 10 10 0 100 0 100
+vtkThresholdTextureCoords thresh1
+    thresh1 SetInput [plane1 GetOutput]
+    thresh1 ThresholdByUpper 1.5
+vtkDataSetMapper plane1Map
+    plane1Map SetInput [thresh1 GetOutput]
+    eval plane1Map SetScalarRange [[pl3d GetOutput] GetScalarRange]
+vtkActor plane1Actor
+    plane1Actor SetMapper plane1Map
+    plane1Actor SetTexture texture
+[plane1Actor GetProperty] SetOpacity 0.999
+
+vtkStructuredGridGeometryFilter plane2
+    plane2 SetInput [pl3d GetOutput]
+    plane2 SetExtent 30 30 0 100 0 100
+vtkThresholdTextureCoords thresh2
+    thresh2 SetInput [plane2 GetOutput]
+    thresh2 ThresholdByUpper 1.5
+vtkDataSetMapper plane2Map
+    plane2Map SetInput [thresh2 GetOutput]
+    eval plane2Map SetScalarRange [[pl3d GetOutput] GetScalarRange]
+vtkActor plane2Actor
+    plane2Actor SetMapper plane2Map
+    plane2Actor SetTexture texture
+    [plane2Actor GetProperty] SetOpacity 0.999
+
+vtkStructuredGridGeometryFilter plane3
+    plane3 SetInput [pl3d GetOutput]
+    plane3 SetExtent 35 35 0 100 0 100
+vtkThresholdTextureCoords thresh3
+    thresh3 SetInput [plane3 GetOutput]
+    thresh3 ThresholdByUpper 1.5
+vtkDataSetMapper plane3Map
+    plane3Map SetInput [thresh3 GetOutput]
+    eval plane3Map SetScalarRange [[pl3d GetOutput] GetScalarRange]
+vtkActor plane3Actor
+    plane3Actor SetMapper plane3Map
+    plane3Actor SetTexture texture
+    [plane3Actor GetProperty] SetOpacity 0.999
+
+# For context create an outline around the data.
+#
+vtkStructuredGridOutlineFilter outline
+    outline SetInput [pl3d GetOutput]
+vtkPolyDataMapper outlineMapper
+    outlineMapper SetInput [outline GetOutput]
+vtkActor outlineActor
+    outlineActor SetMapper outlineMapper
+    set outlineProp [outlineActor GetProperty]
+    eval $outlineProp SetColor 0 0 0
+
+# Create the RenderWindow, Renderer and both Actors
+#
+vtkRenderer ren1
+vtkRenderWindow renWin
+    renWin AddRenderer ren1
+vtkRenderWindowInteractor iren
+    iren SetRenderWindow renWin
+
+# Add the actors to the renderer, set the background and size
+#
+ren1 AddActor outlineActor
+ren1 AddActor wallActor
+ren1 AddActor finActor
+ren1 AddActor plane1Actor
+ren1 AddActor plane2Actor
+ren1 AddActor plane3Actor
+ren1 SetBackground 1 1 1
+renWin SetSize 500 500
+
+# Set up a nice view.
+#
+vtkCamera cam1
+  cam1 SetClippingRange 1.51176 75.5879
+  cam1 SetFocalPoint 2.33749 2.96739 3.61023
+  cam1 SetPosition 10.8787 5.27346 15.8687
+  cam1 SetViewAngle 30
+  cam1 SetViewPlaneNormal 0.564986 0.152542 0.810877
+  cam1 SetViewUp -0.0610856 0.987798 -0.143262
+ren1 SetActiveCamera cam1
+
+iren Initialize
+
+# Set up an observer to invoke a proc when the UserEvent (keypress-u)
+# is invoked.
+#
+iren AddObserver UserEvent {wm deiconify .vtkInteract}
+
+# prevent the tk window from showing up then start the event loop
+wm withdraw .
+
+
+