MOAB: Mesh Oriented datABase
(version 5.4.1)
|
Merge vertices in 2d cell, if they are repeated
To run: QuadTriConv input_file output_file
In this example, a mesh that has vertices repeated due to south or north pole, for example in an rll mesh, need to be converted to triangles, preserving GLOBAL_ID tag
/** @example QuadTriConv.cpp \n * \brief Merge vertices in 2d cell, if they are repeated \n * <b>To run</b>: QuadTriConv input_file output_file \n * * In this example, a mesh that has vertices repeated due to south or north pole, for * example in an rll mesh, need to be converted to triangles, preserving GLOBAL_ID tag */ #include <iostream> #include <vector> //#include <string> // Include header for MOAB instance and tag conventions for #include "moab/Core.hpp" #include "MBTagConventions.hpp" using namespace moab; using namespace std; int main( int argc, char** argv ) { // Get MOAB instance Interface* mb = new( std::nothrow ) Core; if( NULL == mb ) return 1; std::string filename, outfile; outfile = string( "out.h5m" ); if( argc == 1 ) return 0; if( argc > 1 ) filename = string( argv[1] ); if( argc > 2 ) outfile = string( argv[2] ); // This file is in the mesh files directory ErrorCode rval = mb->load_file( filename.c_str() );MB_CHK_SET_ERR( rval, "Failed to read" ); // get all cells of dimension 2; Range cells; rval = mb->get_entities_by_dimension( 0, 2, cells );MB_CHK_SET_ERR( rval, "Failed to get cells" ); cout << " number of cells : " << cells.size() << "\n"; Tag gid; // global id tag rval = mb->tag_get_handle( "GLOBAL_ID", gid );MB_CHK_SET_ERR( rval, "Failed to get Global ID tag" ); Range modifiedCells; // will be deleted at the end; keep the gid for( Range::iterator cit = cells.begin(); cit != cells.end(); cit++ ) { EntityHandle cell = *cit; const EntityHandle* connec = NULL; int num_verts = 0; rval = mb->get_connectivity( cell, connec, num_verts );MB_CHK_SET_ERR( rval, "Failed to get connectivity" ); vector< EntityHandle > newConnec; newConnec.push_back( connec[0] ); // at least one vertex int index = 0; int new_size = 1; while( index < num_verts - 2 ) { int next_index = ( index + 1 ); if( connec[next_index] != newConnec[new_size - 1] ) { newConnec.push_back( connec[next_index] ); new_size++; } index++; } // add the last one only if different from previous and first node if( ( connec[num_verts - 1] != connec[num_verts - 2] ) && ( connec[num_verts - 1] != connec[0] ) ) { newConnec.push_back( connec[num_verts - 1] ); new_size++; } if( new_size < num_verts ) { // cout << "new cell from " << cell << " has only " << new_size << " vertices \n"; modifiedCells.insert( cell ); // create a new cell with type triangle, quad or polygon EntityType type = MBTRI; if( new_size == 3 ) type = MBTRI; else if( new_size == 4 ) type = MBQUAD; else if( new_size > 4 ) type = MBPOLYGON; // create new cell EntityHandle newCell; rval = mb->create_element( type, &newConnec[0], new_size, newCell );MB_CHK_SET_ERR( rval, "Failed to create new cell" ); // set the old id to the new element int id; rval = mb->tag_get_data( gid, &cell, 1, &id );MB_CHK_SET_ERR( rval, "Failed to get global id" ); rval = mb->tag_set_data( gid, &newCell, 1, &id );MB_CHK_SET_ERR( rval, "Failed to set global id on new cell" ); } } mb->delete_entities( modifiedCells ); // in case global ids are not set for vertices, set them, in order; // they are needed for migrating later on // Range verts; rval = mb->get_entities_by_dimension( 0, 0, verts );MB_CHK_SET_ERR( rval, "Failed to get vertices" ); vector< int > gids; gids.resize( verts.size() ); rval = mb->tag_get_data( gid, verts, &gids[0] );MB_CHK_SET_ERR( rval, "Failed to get gids on vertices" ); if( gids[0] <= 0 ) { // gids were never set, assign them for( size_t i = 1; i <= verts.size(); i++ ) gids[i - 1] = (int)i; rval = mb->tag_set_data( gid, verts, &gids[0] );MB_CHK_SET_ERR( rval, "Failed to set gids on vertices" ); } rval = mb->write_file( outfile.c_str() );MB_CHK_SET_ERR( rval, "Failed to write new file" ); cout << " wrote file " << outfile << " with " << modifiedCells.size() << " modified cells\n"; delete mb; return 0; }