TriangleArea
VTKExamples/Cxx/PolyData/TriangleArea
Code¶
TriangleArea.cxx
#include <vtkSmartPointer.h> #include <vtkCellArray.h> #include <vtkPoints.h> #include <vtkPolyData.h> #include <vtkTriangle.h> int main(int, char *[]) { //setup points (geometry) vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New(); points->InsertNextPoint ( 0.0, 0.0, 0.0 ); points->InsertNextPoint ( 1.0, 0.0, 0.0 ); points->InsertNextPoint ( 1.0, 1.0, 0.0 ); points->InsertNextPoint ( 0.0, 1.0, 0.0 ); //create a triangle on the three points in the polydata vtkSmartPointer<vtkTriangle> triangle1 = vtkSmartPointer<vtkTriangle>::New(); triangle1->GetPointIds()->SetId ( 0, 0 ); triangle1->GetPointIds()->SetId ( 1, 1 ); triangle1->GetPointIds()->SetId ( 2, 2 ); vtkSmartPointer<vtkTriangle> triangle2 = vtkSmartPointer<vtkTriangle>::New(); triangle2->GetPointIds()->SetId ( 0, 2 ); triangle2->GetPointIds()->SetId ( 1, 3 ); triangle2->GetPointIds()->SetId ( 2, 0 ); //add the triangles to the list of triangles vtkSmartPointer<vtkCellArray> triangles = vtkSmartPointer<vtkCellArray>::New(); triangles->InsertNextCell ( triangle1 ); triangles->InsertNextCell ( triangle2 ); //create a polydata object vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New(); //add the geometry and topology to the polydata polydata->SetPoints ( points ); polydata->SetPolys ( triangles ); for(vtkIdType i = 0; i < polydata->GetNumberOfCells(); i++) { vtkCell* cell = polydata->GetCell(0); vtkTriangle* triangle = dynamic_cast<vtkTriangle*>(cell); double p0[3]; double p1[3]; double p2[3]; triangle->GetPoints()->GetPoint(0, p0); std::cout << "p0: " << p0[0] << " " << p0[1] << " " << p0[2] << std::endl; triangle->GetPoints()->GetPoint(1, p1); std::cout << "p1: " << p1[0] << " " << p1[1] << " " << p1[2] << std::endl; triangle->GetPoints()->GetPoint(2, p2); std::cout << "p2: " << p2[0] << " " << p2[1] << " " << p2[2] << std::endl; double area = vtkTriangle::TriangleArea(p0, p1, p2); std::cout << "area of triangle " << i << ": " << area << std::endl; } return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(TriangleArea) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(TriangleArea MACOSX_BUNDLE TriangleArea.cxx) target_link_libraries(TriangleArea ${VTK_LIBRARIES})
Download and Build TriangleArea¶
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 Some tarballs may be missing or out-of-date.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 TriangleArea and its CMakeLists.txt file. Once the tarball TriangleArea.tar has been downloaded and extracted,
cd TriangleArea/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:
./TriangleArea
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.