JPhotonPathIO.cc

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#include <iostream>
#include <fstream>

#include "TRandom3.h"

#include "JMarkov/JPhotonPath.hh"
#include "JMarkov/JPhotonPathReader.hh"
#include "JMarkov/JPhotonPathWriter.hh"
using namespace JGEOMETRY3D ;
using namespace JMARKOV ;
using namespace std ;

void printPolyline( JPolyline3D& pl ) {
  for( int i=0 ; i<(int)pl.size()-1 ; ++i ) 
    cout << "(" << pl[i] << ")-" ;
  if( pl.size()>0 ) cout << "(" << pl.back() << ")" ;
}

/**
 * \file Usage example of JPhotonPathReader and JPhotonPathWriter

   Generates a number of random JPhotonPaths and writes them to a file.
   Then reads them back from the same file.
 **/
int main( int argc, char** argv ) {
  // initialization
  TRandom* ran = new TRandom3(0) ;
  const int npaths = 5 ;
  char fname[100] = "out.paths" ;

  // write some example paths to a file
  cout << "Writing some example paths to '" << fname << "'." << endl ;

  JMARKOV::JPhotonPathWriter writer ;
  writer.open(fname) ;
  for( int n=0 ; n<npaths ; ++n ) {
    // create path
    int nscat = ran->Integer(6) ; // how often the photon scatters
    JPhotonPath path(nscat) ;
    // loop over the vertices
    for( JPhotonPath::iterator it=path.begin() ; it!=path.end() ; ++it ) {
      double x = ran->Integer(50) ;
      double y = ran->Integer(50) ;
      double z = ran->Integer(50) ;
      it->setPosition( JGEOMETRY3D::JVector3D(x,y,z) ) ;
    }
    // print the path
    printPolyline( path ) ;
    cout << endl ;
    // write the path
    writer.put(path) ;
  }
  writer.close() ;
  cout << endl ;

  // read paths from a file
  JMARKOV::JPhotonPathReader reader ;
  reader.open("out.paths") ;

  int nread = 0 ;
  JPhotonPath* p = NULL ;
  cout << "Reading file" << endl ;
  while( reader.hasNext() ) {
    p = reader.next() ;
    printPolyline( *p ) ;
    cout << endl ;
    ++nread ;
  }

  cout << "Done reading file. Read " << nread << " paths from it." << endl ;
  cout << endl ;
  cout << "Done!" << endl ;

  return 0 ;
}