Scalars
VTKExamples/Cxx/VTKConcepts/Scalars
Code¶
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) target_link_libraries(Scalars ${VTK_LIBRARIES})
Download and Build Scalars¶
Danger
The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.
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.