ExtractArrayComponent
vtk-examples/Cxx/Utilities/ExtractArrayComponent
Question
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Code¶
ExtractArrayComponent.cxx
#include <vtkArrayCalculator.h>
#include <vtkDoubleArray.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkPolyData.h>
int main(int, char*[])
{
vtkNew<vtkPoints> points;
points->InsertNextPoint(1.0, 0.0, 0.0);
points->InsertNextPoint(2.0, 0.0, 0.0);
points->InsertNextPoint(3.0, 0.0, 0.0);
vtkNew<vtkDoubleArray> array;
array->SetName("InputArray");
array->SetNumberOfComponents(3);
array->InsertNextTuple3(1, 10, 100);
array->InsertNextTuple3(2, 20, 200);
array->InsertNextTuple3(3, 30, 300);
vtkNew<vtkPolyData> polydata;
polydata->SetPoints(points);
polydata->GetPointData()->AddArray(array);
vtkNew<vtkArrayCalculator> arrayCalculator;
arrayCalculator->SetInputData(polydata);
arrayCalculator->AddVectorArrayName("InputArray");
arrayCalculator->SetFunction(
"InputArray . jHat"); // Extract component '1' from the InputArray by
// taking the dot product of each tuple with the
// vector (0,1,0)
arrayCalculator->SetResultArrayName("OutputArray");
arrayCalculator->Update();
vtkSmartPointer<vtkDoubleArray> outputArray = dynamic_cast<vtkDoubleArray*>(
arrayCalculator->GetPolyDataOutput()->GetPointData()->GetArray(
"OutputArray"));
for (vtkIdType i = 0; i < outputArray->GetNumberOfTuples(); i++)
{
double val = outputArray->GetValue(i);
std::cout << "output value " << i << ": " << val << std::endl;
}
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(ExtractArrayComponent)
find_package(VTK COMPONENTS
vtkCommonCore
vtkCommonDataModel
vtkFiltersCore
QUIET
)
if (NOT VTK_FOUND)
message("Skipping ExtractArrayComponent: ${VTK_NOT_FOUND_MESSAGE}")
return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE})
add_executable(ExtractArrayComponent MACOSX_BUNDLE ExtractArrayComponent.cxx )
target_link_libraries(ExtractArrayComponent PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(ExtractArrayComponent MACOSX_BUNDLE ExtractArrayComponent.cxx )
target_link_libraries(ExtractArrayComponent PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS ExtractArrayComponent
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build ExtractArrayComponent¶
Click here to download ExtractArrayComponent and its CMakeLists.txt file. Once the tarball ExtractArrayComponent.tar has been downloaded and extracted,
cd ExtractArrayComponent/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:
./ExtractArrayComponent
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.