MSH_Reader.h

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 * Rocstar Simulation Suite                                          *
 * Copyright@2015, Illinois Rocstar LLC. All rights reserved.        *
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// $Id: MSH_Reader.h,v 1.3 2008/12/06 08:43:24 mtcampbe Exp $

#ifndef MSH_READER_H
#define MSH_READER_H

#include "../Rocsurf/include/surfbasic.h"
#include <vector>
#include <string>
#include <fstream>
#include <cstdlib>
#include <cstdio>
#include <sstream>

COM_EXTERN_MODULE( Rocin);

// This class provides an interface for reading in a surface mesh 
// from the ".smf" or ".obj" file.
class MSH_Reader {
public:
  // Constructor from an MPI communicator and a scale factor.
  MSH_Reader()  {}

  // Assuming the window has been created, read in the local panes from
  // given file and return the number of local panes.
  int read_mesh( const char *fname, const std::string &wname) {
    std::ifstream is( fname); 
    if ( is == NULL) {
      std::cerr << "Error: Could not open file " << fname << std::endl;
      exit(-1);
    }

    // Create the window if not yet exist
    int h=COM_get_window_handle(wname.c_str());
    if ( h<=0) COM_new_window( wname.c_str());

    std::cout << "Reading file " << fname << std::endl;

    read_pane_coors( is, wname);
    read_pane_elems( is, wname);

    return 1;
  }

private:
  void get_nextline( std::istream &is, char *str) {
    str[0] = '\0';
    if ( is.eof()) { return; }
    is.getline( str, MAXLEN); 
  }

  // Read in coordinates of a pane into a window if local
  void read_pane_coors( std::istream &is, const std::string &wname) {
    std::vector<SURF::Point_3<double> >  coors;

    // First, look for number of vertices
    for ( ;;) {
      get_nextline( is, buf);
      std::string s(buf);

      if ( s.find("Vertices",0)!=std::string::npos) break;
    }

    int n=0;
    is >> n; get_nextline(is, buf);
    coors.reserve(n);

    for ( int i=0; i<n; ++i) {
      get_nextline( is, buf);

      SURF::Point_3<double> p;

      std::sscanf( buf, "%lf %lf %lf", &p[0], &p[1], &p[2]);
      coors.push_back( p);
    }

    COM_assertion_msg( n>0, "Did not find any nodes");
    std::cout << "Read in " << n << " nodes" << std::endl;

    COM_set_size( (wname+".nc").c_str(), 1, n);
    SURF::Point_3<double> *p;
    COM_allocate_array( (wname+".nc").c_str(), 1, &(void*&)p);

    std::copy( coors.begin(), coors.end(), p);
  }

  // Read in element connectivity of a pane into a window if local
  void read_pane_elems( std::istream &is, const std::string &wname){
    std::vector<SURF::Vector_3<int> >  elems;

    // First, look for number of triangles
    for (;;) {
      get_nextline( is, buf);
      std::string s(buf);
      
      if ( s.find("Triangles",0)!=std::string::npos) break;
    }

    int n=0;
    is >> n; get_nextline(is, buf);
    elems.reserve(n);

    // When entering this routine, buf[0] should start with 'f'
    for ( int i=0; i<n; ++i) {
      get_nextline( is, buf);

      SURF::Vector_3<int> p;
      std::sscanf( buf, "%d %d %d", &p[0], &p[1], &p[2]);
      elems.push_back( p);
    }

    COM_assertion_msg( n>0, "Did not find any faces");
    std::cout << "Read in " << n << " triangles" << std::endl;

    COM_set_size( (wname+".:t3:").c_str(), 1, n);
    SURF::Vector_3<int> *p;
    COM_allocate_array( (wname+".:t3:").c_str(), 1, &(void*&)p);
    
    std::copy( elems.begin(), elems.end(), p);
  }

private:
  enum  {MAXLEN=255};
  char  buf[MAXLEN+1];
};

#endif