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

From KitwarePublic
< VTK‎ | Examples‎ | Cxx
Jump to navigationJump to search
Line 12: Line 12:
 
int main(int, char *[])
 
int main(int, char *[])
 
{
 
{
   //create points
+
   // Create points
 
   vtkSmartPointer<vtkPoints> points =
 
   vtkSmartPointer<vtkPoints> points =
 
     vtkSmartPointer<vtkPoints>::New();
 
     vtkSmartPointer<vtkPoints>::New();
Line 21: Line 21:
 
   points->InsertNextPoint ( 0.0, 1.0, 0.0 );
 
   points->InsertNextPoint ( 0.0, 1.0, 0.0 );
  
   //add the points to a polydata
+
   // Add the points to a polydata
 
   vtkSmartPointer<vtkPolyData> polydata =
 
   vtkSmartPointer<vtkPolyData> polydata =
 
     vtkSmartPointer<vtkPolyData>::New();
 
     vtkSmartPointer<vtkPolyData>::New();
 
   polydata->SetPoints ( points );
 
   polydata->SetPoints ( points );
  
   //add distances to each point
+
   // Add distances to each point
 
   vtkSmartPointer<vtkDoubleArray> distances =
 
   vtkSmartPointer<vtkDoubleArray> distances =
 
     vtkSmartPointer<vtkDoubleArray>::New();
 
     vtkSmartPointer<vtkDoubleArray>::New();
   distances->SetNumberOfComponents ( 1 );
+
   distances->SetNumberOfComponents(1);
   distances->SetName ( "Distances" );
+
   distances->SetName("Distances");
  
   distances->InsertNextValue ( 1.1 );
+
   distances->InsertNextValue(1.1);
   distances->InsertNextValue ( 2.2 );
+
   distances->InsertNextValue(2.2);
   distances->InsertNextValue ( 3.3 );
+
   distances->InsertNextValue(3.3);
  
 
   polydata->GetPointData()->AddArray ( distances );
 
   polydata->GetPointData()->AddArray ( distances );
  
   //get the distances from the polydata
+
   // Get the distances from the polydata
 
   vtkDoubleArray* array = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
 
   vtkDoubleArray* array = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
  
Line 51: Line 51:
 
     }
 
     }
  
   //cast the double distances to ints
+
   // Cast the double distances to ints
   vtkDoubleArray* doubleDistances = vtkDoubleArray::SafeDownCast ( polydata->GetPointData()->GetArray ( "Distances" ) );
+
   vtkDoubleArray* doubleDistances = vtkDoubleArray::SafeDownCast(
   vtkIntArray* intDistances = vtkIntArray::SafeDownCast ( doubleDistances );
+
                  polydata->GetPointData()->GetArray("Distances"));
 +
   vtkIntArray* intDistances = vtkIntArray::SafeDownCast(doubleDistances);
  
   if ( intDistances )
+
   if(intDistances)
 
     {
 
     {
     for ( unsigned int i = 0; i < numberOfPoints; i++ )
+
     for(unsigned int i = 0; i < numberOfPoints; i++)
 
       {
 
       {
 
       int dist;
 
       int dist;
Line 85: Line 86:
 
TARGET_LINK_LIBRARIES(Casting vtkHybrid)
 
TARGET_LINK_LIBRARIES(Casting vtkHybrid)
 
</source>
 
</source>
 +
 +
[[Category:VTKNoVizRequired]]

Revision as of 14:39, 1 September 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, char *[])
{
  // 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)