VTK/Examples/Cxx/VTKConcepts/Scalars

From KitwarePublic
< VTK‎ | Examples‎ | Cxx
Revision as of 21:50, 9 December 2012 by Lorensen (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Scalars.cxx

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPointData.h>
#include <vtkDoubleArray.h>
#include <vtkFloatArray.h>
 
void TypeSpecific();
void NonTypeSpecific();
 
int main(int, char *[])
{
  TypeSpecific();
  NonTypeSpecific();
 
  return EXIT_SUCCESS;
}
 
void TypeSpecific()
{
  // Create a point set
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->InsertNextPoint(0,0,0);
  points->InsertNextPoint(1,0,0);
 
  vtkSmartPointer<vtkPolyData> polydata =
    vtkSmartPointer<vtkPolyData>::New();
  polydata->SetPoints(points);
 
  vtkSmartPointer<vtkDoubleArray> weights =
    vtkSmartPointer<vtkDoubleArray>::New();
  weights->SetNumberOfValues(2);
  weights->SetValue(0, 1);
  weights->SetValue(1, 2);
 
  polydata->GetPointData()->SetScalars(weights);
 
  double weight = vtkDoubleArray::SafeDownCast(polydata->GetPointData()->GetScalars())->GetValue(0);
  std::cout << "double weight: " << weight << std::endl;
 
  /*
  // This causes a crash because the array is not a vtkFloatArray
  double weightf = vtkFloatArray::SafeDownCast(polydata->GetPointData()->GetScalars())->GetValue(0);
  std::cout << "float weight: " << weightf << std::endl;
  */
}
 
void NonTypeSpecific()
{
  // Create a point set
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->InsertNextPoint(0,0,0);
  points->InsertNextPoint(1,0,0);
 
  vtkSmartPointer<vtkPolyData> polydata =
    vtkSmartPointer<vtkPolyData>::New();
  polydata->SetPoints(points);
 
  vtkSmartPointer<vtkDoubleArray> weights =
    vtkSmartPointer<vtkDoubleArray>::New();
  weights->SetNumberOfValues(2);
  weights->SetValue(0, 1);
  weights->SetValue(1, 2);
 
  polydata->GetPointData()->SetScalars(weights);
 
  double weight = polydata->GetPointData()->GetScalars()->GetComponent(0,0);
  std::cout << "double weight: " << weight << std::endl;
 
  double weightf = polydata->GetPointData()->GetScalars()->GetComponent(0,0);
  std::cout << "float weight: " << weightf << std::endl;
 
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)
 
PROJECT(Scalars)
 
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
 
add_executable(Scalars MACOSX_BUNDLE Scalars.cxx)
 
if(VTK_LIBRARIES)
  target_link_libraries(Scalars ${VTK_LIBRARIES})
else()
  target_link_libraries(Scalars vtkHybrid vtkWidgets)
endif()

Download and Build Scalars

Click here to download Scalars. and its CMakeLists.txt file.

Once the tarball Scalars.tar has been downloaded and extracted,

cd Scalars/build 
  • If VTK is installed:
cmake ..
  • If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./Scalars

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.