support multiple file types and migrate the halfcow to xml

CMakeLists.txt

@@ -11,7 +11,8 @@ set(VTK_COMPONENTS
   VTK::IOLegacy
   VTK::IOGeometry
   VTK::IOXML
-  VTK::FiltersModeling)
+  VTK::FiltersModeling
+  VTK::vtksys)
 set(ENABLE_VIEWER OFF CACHE BOOL "Enable the 3D viewer, depends on Qt.")
 if(ENABLE_VIEWER)
   list(APPEND VTK_COMPONENTS

data/TetMesh2.vtk

@@ -1,20 +0,0 @@
-# vtk DataFile Version 3.0
-vtk output
-ASCII
-DATASET UNSTRUCTURED_GRID
-POINTS 4 float
-0 0 0
-1 0 0
-0 1 0
-0 0 1
-CELLS 1 5
-4 0 1 2 3
-CELL_TYPES 1
-10
-POINT_DATA 4
-SCALARS Indication float
-LOOKUP_TABLE default
-1
-1
-1
-1

src/main.cc

@@ -1,54 +1,73 @@
-#include "angles_filter.h"
-#include "aspect_ratio_filter.h"
 #include "dihedral_angles_filter.h"
+#include "remove_external_cells_filter.h"
 #include "surface_points_filter.h"
 #include "project_surface_points_on_poly.h"
-#include "mesh_fit_filter.h"
-#include "point_tris_dist.h"
-#include "remove_external_cells_filter.h"
 
+#include <vtkCellArrayIterator.h>
 #include <vtkCellData.h>
+#include <vtkDataSetReader.h>
+#include <vtkOBJReader.h>
+#include <vtkPolyData.h>
+#include <vtkPolyDataReader.h>
 #include <vtkUnstructuredGrid.h>
 #include <vtkUnstructuredGridReader.h>
-#include <vtkXMLUnstructuredGridWriter.h>
-#include <vtkPolyData.h>
-#include <vtkCellArrayIterator.h>
 #include <vtkXMLPolyDataReader.h>
-#include <vtkOBJReader.h>
+#include <vtkXMLUnstructuredGridReader.h>
+#include <vtkXMLUnstructuredGridWriter.h>
+#include <vtksys/SystemTools.hxx>
 
 #ifdef USE_VIEWER
-#include <vtkNamedColors.h>
 #include <vtkCamera.h>
-#include <vtkVolumeProperty.h>
+#include <vtkNamedColors.h>
+#include <vtkOpenGLProjectedTetrahedraMapper.h>
+#include <vtkPiecewiseFunction.h>
 #include <vtkRenderWindow.h>
 #include <vtkRenderWindowInteractor.h>
 #include <vtkRenderer.h>
-#include <vtkVolumeMapper.h>
 #include <vtkVolume.h>
-#include <vtkOpenGLProjectedTetrahedraMapper.h>
+#include <vtkVolumeMapper.h>
-#include <vtkPiecewiseFunction.h>
+#include <vtkVolumeProperty.h>
-#endif
+#endif // USE_VIEWER
 
 #include <array>
 
 
+vtkSmartPointer<vtkAlgorithm> readerFromFileName(const char *fileName) {
+	std::string extension =
+		vtksys::SystemTools::GetFilenameLastExtension(fileName);
+	if (extension == ".vtk") {
+		auto reader = vtkDataSetReader::New();
+		reader->SetFileName(fileName);
+		return {reader};
+	} else if (extension == ".vtu") {
+		auto reader = vtkXMLUnstructuredGridReader::New();
+		reader->SetFileName(fileName);
+		return {reader};
+	} else if (extension == ".vtp") {
+		auto reader = vtkXMLPolyDataReader::New();
+		reader->SetFileName(fileName);
+		return {reader};
+	} else if (extension == ".obj") {
+		auto reader = vtkOBJReader::New();
+		reader->SetFileName(fileName);
+		return {reader};
+	}
+	throw std::runtime_error("Invalid file extension.");
+}
+
+
 int main(int argc, char **argv) {
 	if (argc != 3) {
 		std::cerr << "Usage: " << argv[0] << " tetmesh polydata" << std::endl;
 		return EXIT_FAILURE;
 	}
 
-	vtkNew<vtkUnstructuredGridReader> tetMeshReader;
+	auto tetMeshReader = readerFromFileName(argv[1]);
-	tetMeshReader->SetFileName(argv[1]);
+	auto polyMeshReader = readerFromFileName(argv[2]);
 
 	vtkNew<DihedralAnglesFilter> dihedralAnglesFilter;
 	dihedralAnglesFilter->SetInputConnection(tetMeshReader->GetOutputPort());
 
-	// vtkNew<vtkXMLPolyDataReader> polyMeshReader;
-	// polyMeshReader->SetFileName(argv[2]);
-	vtkNew<vtkOBJReader> polyMeshReader;
-	polyMeshReader->SetFileName(argv[2]);
-
 	vtkNew<RemoveExternalCellsFilter> removeExternalCellsFilter;
 	removeExternalCellsFilter->SetInputConnection(0,
 		dihedralAnglesFilter->GetOutputPort());