ReadPlainTextTriangles
VTKExamples/Cxx/IO/ReadPlainTextTriangles
Description
Here is an example of a custom file-format reader that produces a VTK XML PolyData file from a plain-text input format.
Input Format
number_of_points
number_of_triangles
point[point[0]Y point[0](0]X)Z
point[point[1]Y point[1](1]X)Z
...
point[point[N]Y point[N](N]X)Z
triangle[triangle[0]B triangle[0](0]A)C
triangle[triangle[1]B triangle[1](1]A)C
...
triangle[triangle[M]B triangle[M](M]A)C
Example Input
3
1
0.0 0.0 0.0
0.0 0.0 1.0
0.0 1.0 0.0
0 1 2
Code
ReadPlainTextTriangles.cxx
#include "vtkVersion.h"
#include "vtkSmartPointer.h"
#include "vtkPolyData.h"
#include "vtkPoints.h"
#include "vtkCellArray.h"
#include "vtkXMLPolyDataWriter.h"
#include <iostream>
vtkPolyData * custom_reader(std::istream & infile)
{
vtkIdType number_of_points, number_of_triangles;
infile >> number_of_points >> number_of_triangles;
vtkSmartPointer<vtkPoints> points
= vtkSmartPointer<vtkPoints>::New();
points->SetNumberOfPoints(number_of_points);
for (vtkIdType i = 0; i < number_of_points; i++)
{
double x, y, z;
infile >> x >> y >> z;
points->SetPoint(i, x, y, z);
}
vtkSmartPointer<vtkCellArray> polys
= vtkSmartPointer<vtkCellArray>::New();
for (vtkIdType i = 0; i < number_of_triangles; i++)
{
vtkIdType a, b, c;
infile >> a >> b >> c;
polys->InsertNextCell(3);
polys->InsertCellPoint(a);
polys->InsertCellPoint(b);
polys->InsertCellPoint(c);
}
vtkPolyData * polydata = vtkPolyData::New();
polydata->SetPoints(points);
polydata->SetPolys(polys);
return polydata;
}
int main(int argc, char * argv[])
{
// Verify command line arguments
if(argc != 2)
{
std::cerr << "Required arguments: triangleFile.txt" << std::endl;
return EXIT_FAILURE;
}
std::string inputFilename = argv[1];
std::ifstream fin(inputFilename.c_str());
vtkSmartPointer<vtkPolyData> polydata
= vtkSmartPointer<vtkPolyData>::Take(
custom_reader(fin));
vtkSmartPointer<vtkXMLPolyDataWriter> writer =
vtkSmartPointer<vtkXMLPolyDataWriter>::New();
#if VTK_MAJOR_VERSION <= 5
writer->SetInput(polydata);
#else
writer->SetInputData(polydata);
#endif
writer->SetFileName("x.vtp");
writer->Write();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(ReadPlainTextTriangles)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(ReadPlainTextTriangles MACOSX_BUNDLE ReadPlainTextTriangles.cxx)
target_link_libraries(ReadPlainTextTriangles ${VTK_LIBRARIES})
Download and Build ReadPlainTextTriangles
Click here to download ReadPlainTextTriangles and its CMakeLists.txt file. Once the tarball ReadPlainTextTriangles.tar has been downloaded and extracted,
cd ReadPlainTextTriangles/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:
./ReadPlainTextTriangles
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.