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#!/usr/bin/env python
from vtkmodules.vtkCommonCore import (
VTK_STRING,
vtkCommand,
vtkIntArray,
vtkPoints,
)
from vtkmodules.vtkCommonDataModel import vtkPolyData
from vtkmodules.vtkFiltersCore import vtkClipPolyData
from vtkmodules.vtkFiltersModeling import vtkSelectPolyData
from vtkmodules.vtkIOXML import vtkXMLPolyDataReader
from vtkmodules.vtkRenderingCore import (
vtkActor,
vtkPolyDataMapper,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer,
)
import vtkmodules.vtkInteractionStyle
import vtkmodules.vtkRenderingFreeType
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.util.misc import vtkGetDataRoot
VTK_DATA_ROOT = vtkGetDataRoot()
# Callback object to capture errors
class callback:
def __init__(self):
self.reset()
def __call__(self, o, e, d = None):
self.caller = o
self.event = e
self.calldata = d
def reset(self):
self.caller = None
self.event = None
self.calldata = None
reader = vtkXMLPolyDataReader()
reader.SetFileName(VTK_DATA_ROOT + "/Data/cow.vtp")
reader.Update()
# Create a loop around the ear of the cow. It is a somewhat complex area
# where the heuristic greedy edge search method fails but Dijkstra can
# find the path.
loopPointPositions = [[ 4.5208645 , 2.0485868 , -0.5763462 ],
[ 4.5447617 , 1.9674546 , -0.57545805],
[ 4.538317 , 1.8611917 , -0.5673257 ],
[ 4.5059876 , 1.7356979 , -0.55352426],
[ 4.4522295 , 1.5968721 , -0.53562874],
[ 4.381498 , 1.4506135 , -0.51521415],
[ 4.2982492 , 1.3028216 , -0.49385568],
[ 4.206939 , 1.1593955 , -0.47312826],
[ 4.112025 , 1.0262344 , -0.454607 ],
[ 4.0179615 , 0.9092375 , -0.43986693],
[ 3.9292052 , 0.8143042 , -0.43048313],
[ 3.8492908 , 0.74591345, -0.42754683],
[ 3.7780685 , 0.7028636 , -0.430214 ],
[ 3.7144666 , 0.68253285, -0.43715683],
[ 3.657414 , 0.6822994 , -0.44704747],
[ 3.605839 , 0.6995413 , -0.4585581 ],
[ 3.5586705 , 0.7316368 , -0.47036093],
[ 3.514837 , 0.7759641 , -0.4811281 ],
[ 3.4732673 , 0.8299013 , -0.4895318 ],
[ 3.43289 , 0.8908266 , -0.49424416],
[ 3.3926337 , 0.9561181 , -0.4939374 ],
[ 3.3520544 , 1.023584 , -0.48774803],
[ 3.3132184 , 1.0927521 , -0.47666985],
[ 3.2788188 , 1.1635803 , -0.4621611 ],
[ 3.2515495 , 1.2360263 , -0.4456799 ],
[ 3.2341034 , 1.3100479 , -0.42868453],
[ 3.2291746 , 1.385603 , -0.4126331 ],
[ 3.2394562 , 1.4626493 , -0.39898378],
[ 3.267642 , 1.5411446 , -0.38919482],
[ 3.316425 , 1.6210469 , -0.38472438],
[ 3.388499 , 1.7023138 , -0.38703063],
[ 3.4850955 , 1.784371 , -0.3970445 ],
[ 3.6015983 , 1.8645154 , -0.41358784],
[ 3.731929 , 1.9395119 , -0.43495524],
[ 3.8700097 , 2.0061252 , -0.4594413 ],
[ 4.0097623 , 2.0611203 , -0.48534057],
[ 4.145108 , 2.1012616 , -0.5109477 ],
[ 4.2699695 , 2.1233141 , -0.5345572 ],
[ 4.3782682 , 2.1240425 , -0.55446374],
[ 4.463926 , 2.1002119 , -0.5689619 ],
[ 4.5208645 , 2.0485868 , -0.5763462 ]]
loopPoints = vtkPoints()
for xyz in loopPointPositions:
loopPoints.InsertNextPoint(xyz)
# Add attribute information
cowPolyData = vtkPolyData()
cowPolyData.ShallowCopy(reader.GetOutput())
ptScalarArray = vtkIntArray()
ptScalarArray.SetName("ScalarArray")
ptScalarArray.SetNumberOfComponents(1)
ptScalarArray.SetNumberOfTuples(cowPolyData.GetNumberOfPoints())
ptScalarArray.Fill(1)
cowPolyData.GetPointData().AddArray(ptScalarArray)
cellScalarArray = vtkIntArray()
cellScalarArray.SetName("ScalarArray")
cellScalarArray.SetNumberOfComponents(1)
cellScalarArray.SetNumberOfTuples(cowPolyData.GetNumberOfCells())
cellScalarArray.Fill(1)
cowPolyData.GetCellData().AddArray(cellScalarArray)
# Filter setup
selectionFilter = vtkSelectPolyData()
selectionFilter.SetInputData(cowPolyData)
selectionFilter.SetLoop(loopPoints)
selectionFilter.GenerateSelectionScalarsOn()
selectionFilter.SetSelectionScalarsArrayName("SelectionArray")
selectionFilter.SetSelectionModeToSmallestRegion()
# Run selection filter using greedy method (expected to fail)
# Add error observer to catch the expected error (uncaught error would make the test fail)
cb = callback()
cb.CallDataType = VTK_STRING
observerId = selectionFilter.AddObserver(vtkCommand.ErrorEvent, cb)
# Run the computation
selectionFilter.SetEdgeSearchModeToGreedy()
selectionFilter.Update()
# Remove the error observer
selectionFilter.RemoveObserver(observerId)
# Check the results
if cb.event:
print("As expected, greedy edge search failed: %s" % cb.calldata)
numberOfOutputPoints = selectionFilter.GetOutput().GetNumberOfPoints()
print("Number of points extracted using greedy edge search (0 means failure): %d" % numberOfOutputPoints)
# Run selection filter using Dijkstra method (expected to succeed)
# Run the computation
selectionFilter.SetEdgeSearchModeToDijkstra()
selectionFilter.Update()
# Check the results
numberOfOutputPoints = selectionFilter.GetOutput().GetNumberOfPoints()
print("Number of points extracted using Dijkstra edge search (0 means failure): %d" % numberOfOutputPoints)
if numberOfOutputPoints == 0:
raise ValueError("Dijkstra edge search failed.")
testArray = selectionFilter.GetOutput().GetPointData().GetArray("SelectionArray")
if testArray is None:
raise ValueError("Selection scalar array failed to generate using Dijkstra edge search.")
# Selection array range (signed distance from the loop) is expected to be about (-0.421, 8.379).
# If minimum or maximum of the range is near zero on one side then it means that the algorithm failed to split the surface.
if testArray.GetRange()[0] > -0.1:
raise ValueError("Selection scalar array failed to generate using Dijkstra edge search: larger negative range is expected.")
if testArray.GetRange()[1] < 0.1:
raise ValueError("Selection scalar array failed to generate using Dijkstra edge search: larger positive range is expected.")
testPtScalarArray = selectionFilter.GetOutput().GetPointData().GetArray("ScalarArray")
if testPtScalarArray is None:
raise ValueError("Point scalar array did not pass through using Dijkstra edge search.")
testCellScalarArray = selectionFilter.GetOutput().GetCellData().GetArray("ScalarArray")
if testCellScalarArray is None:
raise ValueError("Cell scalar array did not pass through using Dijkstra edge search.")
# Display results
# Clip the mesh with the selection (cuts out a hole around the cow's ear)
clipFilter = vtkClipPolyData()
clipFilter.SetInputConnection(selectionFilter.GetOutputPort())
# Set up renderer
ren1 = vtkRenderer()
renWin = vtkRenderWindow()
renWin.AddRenderer(ren1)
iren = vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)
# Set up actor
mapper = vtkPolyDataMapper()
mapper.SetInputConnection(clipFilter.GetOutputPort())
actor = vtkActor()
actor.SetMapper(mapper)
ren1.AddActor(actor)
# Set up view
ren1.GetActiveCamera().Azimuth(140)
ren1.ResetCamera()
renWin.SetSize(300,300)
renWin.Render()
# Uncomment for interactive rendering
# iren.Start()
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