unpartmesh_01a_readfromvtu.cc

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#include "chi_unpartitioned_mesh.h"
 
#include "mesh/MeshContinuum/chi_grid_vtk_utils.h"
 
#include <vtkSmartPointer.h>
#include <vtkUnstructuredGrid.h>
#include <vtkXMLUnstructuredGridReader.h>
 
#include <vtkInformation.h>
 
#include "chi_runtime.h"
#include "chi_log.h"
 
#define ErrorReadingFile(fname)                                                \
  std::runtime_error("Failed to open file: " + options.file_name +             \
                     " in call to " + #fname + ".")
 
// ###################################################################
/**Reads a VTK unstructured mesh. This reader will use the following
 * options:
 * - `file_name`, of course.
 * - `material_id_fieldname`, cell data for material_id.*/
void chi_mesh::UnpartitionedMesh::ReadFromVTU(
  const chi_mesh::UnpartitionedMesh::Options& options)
{
  Chi::log.Log() << "Reading VTU file: " << options.file_name << ".";
 
  //======================================== Attempt to open file
  std::ifstream file;
  file.open(options.file_name);
  if (!file.is_open()) throw ErrorReadingFile(ReadFromVTU);
  file.close();
 
  //======================================== Read the file
  mesh_options_ = options;
  auto reader = vtkSmartPointer<vtkXMLUnstructuredGridReader>::New();
  reader->SetFileName(options.file_name.c_str());
 
  if (not reader->CanReadFile(options.file_name.c_str()))
    throw std::logic_error("Unable to read file-type with this routine");
  reader->UpdateInformation();
  reader->Update();
 
  //======================================== Get all the grid blocks
  // For vtu files this is very simple. The
  // output of the reader is an UnstructuredGrid.
  auto ugrid_main = vtkUGridPtr(reader->GetOutput());
  std::vector<vtkUGridPtrAndName> grid_blocks = {{ugrid_main, ""}};
 
  //======================================== Get the main + bndry blocks
  const int max_dimension = chi_mesh::FindHighestDimension(grid_blocks);
  Chi::log.Log0Verbose1() << "Maximum dimension : " << max_dimension << "\n";
  std::vector<vtkUGridPtrAndName> domain_grid_blocks =
    chi_mesh::GetBlocksOfDesiredDimension(grid_blocks, max_dimension);
  std::vector<vtkUGridPtrAndName> bndry_grid_blocks =
    chi_mesh::GetBlocksOfDesiredDimension(grid_blocks, max_dimension - 1);
 
  //======================================== Process blocks
  auto ugrid = chi_mesh::ConsolidateGridBlocks(
    domain_grid_blocks, mesh_options_.material_id_fieldname);
 
  //======================================== Copy Data
  CopyUGridCellsAndPoints(*ugrid, options.scale, max_dimension);
 
  //======================================== Set material ids
  const auto material_ids = chi_mesh::BuildCellMaterialIDsFromField(
    ugrid, options.material_id_fieldname, options.file_name);
  SetMaterialIDsFromList(material_ids);
 
  //======================================== Always do this
  chi_mesh::MeshAttributes dimension = NONE;
  switch (max_dimension)
  {
    case 1:
      dimension = DIMENSION_1;
      break;
    case 2:
      dimension = DIMENSION_2;
      break;
    case 3:
      dimension = DIMENSION_3;
      break;
    default:
      break;
  }
 
  attributes_ = dimension | UNSTRUCTURED;
 
  ComputeCentroidsAndCheckQuality();
  BuildMeshConnectivity();
 
  Chi::log.Log() << "Done reading VTU file: " << options.file_name << ".";
}