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QuadraticHexahedronDemo

vtk-examples/Python/GeometricObjects/QuadraticHexahedronDemo

Description

This example shows the effect of changing the chord length error for a vtkQuadraticHexahedron.

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Question

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Code

QuadraticHexahedronDemo.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# noinspection PyUnresolvedReferences
import vtkmodules.vtkInteractionStyle
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonCore import (
    vtkCommand,
    vtkMinimalStandardRandomSequence,
    vtkPoints
)
from vtkmodules.vtkCommonDataModel import (
    vtkGenericCell,
    vtkQuadraticHexahedron,
    vtkUnstructuredGrid
)
from vtkmodules.vtkFiltersCore import vtkGlyph3D
from vtkmodules.vtkFiltersGeneral import vtkTessellatorFilter
from vtkmodules.vtkFiltersSources import vtkSphereSource
from vtkmodules.vtkInteractionWidgets import (
    vtkSliderRepresentation2D,
    vtkSliderWidget
)
from vtkmodules.vtkRenderingCore import (
    vtkActor,
    vtkActor2D,
    vtkDataSetMapper,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
    vtkRenderer,
    vtkTextMapper,
    vtkTextProperty
)


def main():
    namedColors = vtkNamedColors()

    uGrid = MakeQuadraticHexahedron()

    tessellate = vtkTessellatorFilter()
    tessellate.SetInputData(uGrid)
    tessellate.SetChordError(0.035)
    tessellate.Update()

    cellMap = dict()

    numTets = 0
    cell = vtkGenericCell()
    it = tessellate.GetOutput().NewCellIterator()
    it.InitTraversal()
    while not it.IsDoneWithTraversal():
        it.GetCell(cell)
        cellMap[cell.GetRepresentativeCell().GetClassName()] = numTets
        numTets += 1
        it.GoToNextCell()

    mapper = vtkDataSetMapper()
    mapper.SetInputConnection(tessellate.GetOutputPort())
    mapper.ScalarVisibilityOff()

    # Create an actor for the grid
    actor = vtkActor()
    actor.SetMapper(mapper)
    actor.GetProperty().SetDiffuseColor(
        namedColors.GetColor3d('Tomato'))
    actor.GetProperty().SetEdgeColor(
        namedColors.GetColor3d('IvoryBlack'))
    actor.GetProperty().EdgeVisibilityOn()

    sphereSource = vtkSphereSource()
    sphereSource.SetRadius(0.02)

    glyph3D = vtkGlyph3D()
    glyph3D.SetInputData(uGrid)
    glyph3D.SetSourceConnection(sphereSource.GetOutputPort())
    glyph3D.ScalingOff()
    glyph3D.Update()

    glyph3DMapper = vtkDataSetMapper()
    glyph3DMapper.SetInputConnection(glyph3D.GetOutputPort())
    glyph3DMapper.ScalarVisibilityOff()

    glyph3DActor = vtkActor()
    glyph3DActor.SetMapper(glyph3DMapper)
    glyph3DActor.GetProperty().SetColor(
        namedColors.GetColor3d('Banana'))

    textProperty = vtkTextProperty()
    textProperty.SetFontSize(24)

    ss = '# of Tetras: ' + str(numTets)
    textMapper = vtkTextMapper()
    textMapper.SetInput(ss)
    textMapper.SetTextProperty(textProperty)

    textActor = vtkActor2D()
    textActor.SetMapper(textMapper)
    textActor.SetPosition(10, 400)

    # Visualize
    renderer = vtkRenderer()
    renderWindow = vtkRenderWindow()
    renderWindow.SetWindowName('QuadraticHexahedronDemo')
    renderWindow.AddRenderer(renderer)
    renderWindow.SetSize(640, 512)
    interactor = vtkRenderWindowInteractor()
    interactor.SetRenderWindow(renderWindow)

    widget = vtkSliderWidget()
    MakeWidget(widget, tessellate, textMapper, interactor)

    renderer.AddActor(actor)
    renderer.AddActor(glyph3DActor)
    renderer.AddViewProp(textActor)
    renderer.SetBackground(namedColors.GetColor3d('SlateGray'))

    renderWindow.Render()

    interactor.Start()


class SliderCallbackChordError():
    def __init__(self, tessellate, textMapper):
        self.tessellate = tessellate
        self.textMapper = textMapper

    def __call__(self, caller, ev):
        sliderWidget = caller
        value = sliderWidget.GetRepresentation().GetValue()
        self.tessellate.SetChordError(value)
        self.tessellate.SetMaximumNumberOfSubdivisions(4)
        self.tessellate.Update()

        cellMap = dict()

        numTets = 0
        cell = vtkGenericCell()
        it = self.tessellate.GetOutput().NewCellIterator()
        it.InitTraversal()
        while not it.IsDoneWithTraversal():
            it.GetCell(cell)
            cellMap[cell.GetRepresentativeCell().GetClassName()] = numTets
            numTets += 1
            it.GoToNextCell()
        ss = '# of Tetras: ' + str(numTets)
        self.textMapper.SetInput(ss)


def MakeWidget(widget, tessellate, textMapper, interactor):
    # Setup a slider widget for each varying parameter
    tubeWidth = 0.008
    sliderLength = 0.008
    titleHeight = 0.04
    labelHeight = 0.04

    sliderRepChordError = vtkSliderRepresentation2D()

    sliderRepChordError.SetMinimumValue(0.0)
    sliderRepChordError.SetMaximumValue(0.07)
    sliderRepChordError.SetValue(tessellate.GetChordError())
    sliderRepChordError.SetTitleText('Chord error')

    sliderRepChordError.GetPoint1Coordinate().SetCoordinateSystemToNormalizedDisplay()
    sliderRepChordError.GetPoint1Coordinate().SetValue(0.1, 0.1)
    sliderRepChordError.GetPoint2Coordinate().SetCoordinateSystemToNormalizedDisplay()
    sliderRepChordError.GetPoint2Coordinate().SetValue(0.9, 0.1)

    sliderRepChordError.SetTubeWidth(tubeWidth)
    sliderRepChordError.SetSliderLength(sliderLength)
    sliderRepChordError.SetTitleHeight(titleHeight)
    sliderRepChordError.SetLabelHeight(labelHeight)

    widget.SetInteractor(interactor)
    widget.SetRepresentation(sliderRepChordError)
    widget.SetAnimationModeToAnimate()
    widget.EnabledOn()

    widget.AddObserver(vtkCommand.InteractionEvent, SliderCallbackChordError(tessellate, textMapper))


def MakeQuadraticHexahedron():
    aHexahedron = vtkQuadraticHexahedron()
    points = vtkPoints()

    pcoords = aHexahedron.GetParametricCoords()
    rng = vtkMinimalStandardRandomSequence()
    points.SetNumberOfPoints(aHexahedron.GetNumberOfPoints())
    rng.SetSeed(5070)  # for testing
    for i in range(0, aHexahedron.GetNumberOfPoints()):
        perturbation = [0.0] * 3
        for j in range(0, 3):
            rng.Next()
            perturbation[j] = rng.GetRangeValue(-0.1, 0.1)
        aHexahedron.GetPointIds().SetId(i, i)
        points.SetPoint(i, pcoords[3 * i] + perturbation[0],
                        pcoords[3 * i + 1] + perturbation[1],
                        pcoords[3 * i + 2] + perturbation[2])

    # Add the points and hexahedron to an unstructured grid
    uGrid = vtkUnstructuredGrid()
    uGrid.SetPoints(points)
    uGrid.InsertNextCell(aHexahedron.GetCellType(), aHexahedron.GetPointIds())

    return uGrid


if __name__ == '__main__':
    main()