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| − | This example creates a polydata object with 3 points and attaches a distance value to each point. To retrieve the array from the polydata, we have to use a SafeDownCast to the type that we want. This is necessary because to keep things as general as possible the polydata will return an abstract array class.
| + | = '''See [https://lorensen.github.io/VTKExamples/site/Cxx/PolyData/Casting Casting] on the new [https://lorensen.github.io/VTKExamples/site/ VTKExamples website].''' = |
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| − | ==Casting.cxx==
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| − | <source lang="cpp">
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| − | #include <vtkSmartPointer.h>
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| − | #include <vtkDoubleArray.h>
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| − | #include <vtkIntArray.h>
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| − | #include <vtkPoints.h>
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| − | #include <vtkPolyData.h>
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| − | #include <vtkPointData.h>
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| − | int main ( int argc, char *argv[] )
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| − | {
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| − | //create points
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| − | vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
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| − | | |
| − | unsigned int numberOfPoints = 3;
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| − | points->InsertNextPoint ( 0.0, 0.0, 0.0 );
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| − | points->InsertNextPoint ( 1.0, 0.0, 0.0 );
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| − | points->InsertNextPoint ( 0.0, 1.0, 0.0 );
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| − | | |
| − | //add the points to a polydata
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| − | vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New();
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| − | polydata->SetPoints ( points );
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| − | //add distances to each point
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| − | vtkSmartPointer<vtkDoubleArray> distances = vtkSmartPointer<vtkDoubleArray>::New();
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| − | distances->SetNumberOfComponents ( 1 );
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| − | distances->SetName ( "Distances" );
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| − | distances->InsertNextValue ( 1.1 );
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| − | distances->InsertNextValue ( 2.2 );
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| − | distances->InsertNextValue ( 3.3 );
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| − | polydata->GetPointData()->AddArray ( distances );
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| − | | |
| − | //get the distances from the polydata
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| − | vtkDoubleArray* array = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
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| − | | |
| − | if ( Array )
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| − | {
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| − | for ( unsigned int i = 0; i < NumberOfPoints; i++ )
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| − | {
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| − | double dist;
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| − | dist = array->GetValue ( i );
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| − | vtkstd::cout << "Distance: " << dist << vtkstd::endl;
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| − | }
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| − | }
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| − | | |
| − | //cast the double distances to ints
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| − | vtkDoubleArray* doubleDistances = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
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| − | vtkIntArray* intDistances = vtkIntArray::SafeDownCast ( doubleDistances );
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| − | | |
| − | if ( intDistances )
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| − | {
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| − | for ( unsigned int i = 0; i < numberOfPoints; i++ )
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| − | {
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| − | int dist;
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| − | dist = intDistances->GetValue ( i );
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| − | vtkstd::cout << "Distance: " << dist << vtkstd::endl;
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| − | }
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| − | }
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| − | else
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| − | {
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| − | vtkstd::cout << "invalid cast." << vtkstd::endl;
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| − | }
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| − | return 0;
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| − | }
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| − | | |
| − | | |
| − | </source>
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| − | | |
| − | ==CMakeLists.txt==
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| − | <source lang="text">
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| − | cmake_minimum_required(VERSION 2.6)
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| − | PROJECT(Casting)
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| − | FIND_PACKAGE(VTK REQUIRED)
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| − | INCLUDE(${VTK_USE_FILE})
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| − | | |
| − | ADD_EXECUTABLE(Casting Casting.cxx)
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| − | TARGET_LINK_LIBRARIES(Casting vtkHybrid)
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| − | </source>
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