Difference between revisions of "VTK/Examples/Cxx/PolyData/Casting"

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(This example never compiled.)
Line 13: Line 13:
 
{
 
{
 
   //create points
 
   //create points
   vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
+
   vtkSmartPointer<vtkPoints> points =
 +
    vtkSmartPointer<vtkPoints>::New();
  
 
   unsigned int numberOfPoints = 3;
 
   unsigned int numberOfPoints = 3;
Line 21: Line 22:
  
 
   //add the points to a polydata
 
   //add the points to a polydata
   vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New();
+
   vtkSmartPointer<vtkPolyData> polydata =
 +
    vtkSmartPointer<vtkPolyData>::New();
 
   polydata->SetPoints ( points );
 
   polydata->SetPoints ( points );
  
 
   //add distances to each point
 
   //add distances to each point
   vtkSmartPointer<vtkDoubleArray> distances = vtkSmartPointer<vtkDoubleArray>::New();
+
   vtkSmartPointer<vtkDoubleArray> distances =
 +
    vtkSmartPointer<vtkDoubleArray>::New();
 
   distances->SetNumberOfComponents ( 1 );
 
   distances->SetNumberOfComponents ( 1 );
 
   distances->SetName ( "Distances" );
 
   distances->SetName ( "Distances" );
Line 38: Line 41:
 
   vtkDoubleArray* array = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
 
   vtkDoubleArray* array = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
  
   if ( Array )
+
   if ( array )
 
     {
 
     {
     for ( unsigned int i = 0; i < NumberOfPoints; i++ )
+
     for ( unsigned int i = 0; i < numberOfPoints; i++ )
 
       {
 
       {
 
       double dist;
 
       double dist;
 
       dist = array->GetValue ( i );
 
       dist = array->GetValue ( i );
       vtkstd::cout << "Distance: " << dist << vtkstd::endl;
+
       std::cout << "Distance: " << dist << std::endl;
 
       }
 
       }
 
     }
 
     }
Line 58: Line 61:
 
       int dist;
 
       int dist;
 
       dist = intDistances->GetValue ( i );
 
       dist = intDistances->GetValue ( i );
       vtkstd::cout << "Distance: " << dist << vtkstd::endl;
+
       std::cout << "Distance: " << dist << std::endl;
 
       }
 
       }
 
     }
 
     }
 
   else
 
   else
 
     {
 
     {
     vtkstd::cout << "invalid cast." << vtkstd::endl;
+
     std::cout << "invalid cast." << std::endl;
 
     }
 
     }
  
   return 0;
+
   return EXIT_SUCCESS;
 
}
 
}
 
  
 
</source>
 
</source>

Revision as of 15:54, 3 May 2010

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.

Casting.cxx

#include <vtkSmartPointer.h>
#include <vtkDoubleArray.h>
#include <vtkIntArray.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPointData.h>

int main ( int argc, char *argv[] )
{
  //create points
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();

  unsigned int numberOfPoints = 3;
  points->InsertNextPoint ( 0.0, 0.0, 0.0 );
  points->InsertNextPoint ( 1.0, 0.0, 0.0 );
  points->InsertNextPoint ( 0.0, 1.0, 0.0 );

  //add the points to a polydata
  vtkSmartPointer<vtkPolyData> polydata =
    vtkSmartPointer<vtkPolyData>::New();
  polydata->SetPoints ( points );

  //add distances to each point
  vtkSmartPointer<vtkDoubleArray> distances =
    vtkSmartPointer<vtkDoubleArray>::New();
  distances->SetNumberOfComponents ( 1 );
  distances->SetName ( "Distances" );

  distances->InsertNextValue ( 1.1 );
  distances->InsertNextValue ( 2.2 );
  distances->InsertNextValue ( 3.3 );

  polydata->GetPointData()->AddArray ( distances );

  //get the distances from the polydata
  vtkDoubleArray* array = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );

  if ( array )
    {
    for ( unsigned int i = 0; i < numberOfPoints; i++ )
      {
      double dist;
      dist = array->GetValue ( i );
      std::cout << "Distance: " << dist << std::endl;
      }
    }

  //cast the double distances to ints
  vtkDoubleArray* doubleDistances = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
  vtkIntArray* intDistances = vtkIntArray::SafeDownCast ( doubleDistances );

  if ( intDistances )
    {
    for ( unsigned int i = 0; i < numberOfPoints; i++ )
      {
      int dist;
      dist = intDistances->GetValue ( i );
      std::cout << "Distance: " << dist << std::endl;
      }
    }
  else
    {
    std::cout << "invalid cast." << std::endl;
    }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.6)
PROJECT(Casting)

FIND_PACKAGE(VTK REQUIRED)
INCLUDE(${VTK_USE_FILE})

ADD_EXECUTABLE(Casting Casting.cxx)
TARGET_LINK_LIBRARIES(Casting vtkHybrid)