#!/usr/bin/perl

## place_on_mesh
##
## author: D. ElTom
## version: 1.1
## laste modified: 21. Sep. 2005
##
## description:
## PERL-Script that reads an include file with ONE mesh description in POVRay mesh2 format
## and will write an POVRay include file with arrays for positions and corresponding normals.
##
## usage:
## [perl] place_on_mesh [options] -i <infile> [-o <outfile>]
##
## linux: make the script executable and run it.
## window$: you may have to call perl interpreter and pass name of script as 1. argument
##
## parameters:
## -i <infile>  : specify the name of the file to be parsed
## -o <outfile> : specify the name of the file to be generated [default = output.inc]
## -s           : create seperate files for positions, normals and uv's
##                output filename will be used as base name.
## -d <desnity> : specify density [default = 100]

use POSIX;

%program_options = ("infile" => "infile.inc", "outfile" => "output.inc", "seperate" => "0", "density" => "100");

# vertex data
$vertex_count;
@vert_x;
@vert_y;
@vert_z;
# normal data
$normal_count;
@norm_x;
@norm_y;
@norm_z;
# texture coordinate data
$has_texcoord = 0;
$texcoord_count;
@tex_u;
@tex_v;

# facette information
$face_count;
@v1_id;
@v2_id;
@v3_id;
@n1_id;
@n2_id;
@n3_id;
@t1_id;
@t2_id;
@t3_id;

$total_area = 0;
@areas;

$approx_placements;
$total_placements;
@pv_x;
@pv_y;
@pv_z;
@pn_x;
@pn_y;
@pn_z;
@puv_u;
@puv_v;

# greeting (mode)
# prints a short message
# if mode is 1 then include a short help
sub greeting # mode
{
  $verbose = $_[0];
  print "PLACE ON MESH (V1.1)\n";
  print "--------------------\n\n";
  if ($verbose==1)
  {
    print "usage:\n";
    print "[perl] place_on_mesh [options] -i <infile> \n\n";
    print "parameters:\n";
    print " -i <infile>  : specify the name of the file to be parsed\n";
    print " -o <outfile> : specify the name of the file to be generated [default = output.inc]\n";
    print " -s           : create seperate files for positions, normals and uv's\n";
    print "                output filename will be used as base name.\n";
    print " -d <desnity> : specify density [default = 100]\n";
  }
}

# read_program_arguments
# parse the comand line parameters
sub read_program_arguments # void
{
  $number_of_arguments = $#ARGV + 1;
  if ($number_of_arguments == 0)
  {
    greeting(1);
    exit();
  }
  else
  {
    greeting(0);
    $arguments_read = 0;
    $infile_given = 0;
    while ($arguments_read < $number_of_arguments)
    {
      $argument = $ARGV[$arguments_read];
      $arguments_read++;
      if ($argument =~ m/\A[^-]/)
      {
        print " don't know what to do with argument $argument\n";
        exit();
      }
      else
      {
         if ($argument =~ m/-[iosdIOSD]/g)
         {
           $known_argument = substr($argument,1,1);
           if ($known_argument =~ m/i/g)
           {
             # input file name sepcification
             if (length($argument) > 2)
             {
               # assume file name was written without space as seperator
               $program_options{infile} = substr($argument,2,(length($argument)-2));
             }
             else
             {
               # assume file name was written wiht space as seperator
               $program_options{infile} = $ARGV[$arguments_read];
               $arguments_read++;
             }
             #print " ... will use $program_options{infile} as input ...\n";
             $infile_given = 1;
           }
           if ($known_argument =~ m/o/g)
           {
             # output file name sepcification
             if (length($argument) > 2)
             {
               # assume file name was written without space as seperator
               $program_options{outfile} = substr($argument,2,(length($argument)-2));
             }
             else
             {
               # assume file name was written wiht space as seperator
               $program_options{outfile} = $ARGV[$arguments_read];
               $arguments_read++;
             }
           }
           if ($known_argument =~ m/d/g)
           {
             # density sepcification
             if (length($argument) > 2)
             {
               # assume density was written without space as seperator
               $program_options{density} = substr($argument,2,(length($argument)-2));
             }
             else
             {
               # assume density was written wiht space as seperator
               $program_options{density} = $ARGV[$arguments_read];
               $arguments_read++;
             }
             # test if given density is a positiv number
             if ($program_options{density} =~ m/[^\+0-9\.]/g)
             {
               print " density have to be a positive number\n";
               exit();
             }
           }
           if ($known_argument =~ m/s/g)
           {
             $program_options{seperate} = 1;
           }
         }
         else
         {
           @unknown_argument = $argument =~ m/-\w/g;
           print " unkown option @unknown_argument\n";
           exit();
         }
      }
    }
    if ($infile_given == 0)
    {
       print " you must specify a valid input file\n";
       exit(); 
    }
    # short summary
    print " ... using $program_options{infile} as input ...\n";
    if ($program_options{seperate} == 0)
    {
      print " ... using $program_options{outfile} for output ...\n";
    }
    else
    {
       @outputfilename = split(/\./,$program_options{outfile});
       $p_filename = $outputfilename[0] . "_p." . $outputfilename[1];
       $n_filename = $outputfilename[0] . "_n." . $outputfilename[1];
       $uv_filename = $outputfilename[0] . "_uv." . $outputfilename[1];
       print " ... using $p_filename, $n_filename and $uv_filename for output ...\n";
    }
    print " ... using a density of $program_options{density} ...\n";
  }
}

# parse_input_file (filename)
sub parse_input_file # filename
{
  $filename = $_[0];
  print " ... opening $filename for reading ... ";
  open(INFILE,"<$filename") || die "failed\n";
  print "ok\n";

  while ($line = <INFILE>)
  {
    if ($line =~ m/vertex_vectors/g)
    {
      $line = <INFILE>;
      @regex_result = $line =~ m/\d+/g;
      foreach(@regex_result)
      {
        if (length($_) > 0)
        {
          $vertex_count = $_;
        }
      }
      print " ... reading $vertex_count vertices ... ";
      for ($counter = 0; $counter < $vertex_count; $counter++)
      {
        $line = <INFILE>;
        @regex_result = $line =~ m/-?\d*\.?\d*[eE]?-?\d*/g;
        $n = 0;
        foreach(@regex_result)
        {
          if (length($_) > 0)
          {
            $v_coord[$n] = $_;
            $n++;
          }
        }
        push(@vert_x, $v_coord[0]);
        push(@vert_y, $v_coord[1]);
        push(@vert_z, $v_coord[2]);
      }
      print "ok\n";
    }
    if ($line =~ m/normal_vectors/g)
    {
      $line = <INFILE>;
      @regex_result = $line =~ m/\d+/g;
      foreach(@regex_result)
      {
        if (length($_) > 0)
        {
          $normal_count = $_;
        }
      }
      print " ... reading $normal_count normals ... ";
      for ($counter = 0; $counter < $normal_count; $counter++)
      {
        $line = <INFILE>;
        @regex_result = $line =~ m/-?\d*\.?\d*[eE]?-?\d*/g;
        $n = 0;
        foreach(@regex_result)
        {
          if (length($_) > 0)
          {
            $n_coord[$n] = $_;
            $n++;
          }
        }
        push(@norm_x, $n_coord[0]);
        push(@norm_y, $n_coord[1]);
        push(@norm_z, $n_coord[2]);
      }
      print "ok\n";
    }
    if ($line =~ m/uv_vectors/g)
    {
      $has_texcoord = 1;
      $line = <INFILE>;
      @regex_result = $line =~ m/\d+/g;
      foreach(@regex_result)
      {
        if (length($_) > 0)
        {
          $texcoord_count = $_;
        }
      }
      print " ... reading $texcoord_count texture coordinates ... ";
      for ($counter = 0; $counter < $texcoord_count; $counter++)
      {
        $line = <INFILE>;
        @regex_result = $line =~ m/-?\d*\.?\d*[eE]?-?\d*/g;
        $n = 0;
        foreach(@regex_result)
        {
          if (length($_) > 0)
          {
            $tex_coord[$n] = $_;
            $n++;
          }
        }
        push(@tex_u, $tex_coord[0]);
        push(@tex_v, $tex_coord[1]);
        #print "$tex_coord[0], $tex_coord[1]\n";
      }
      print "ok\n";
    }
    if ($line =~ m/face_indices/g)
    {
      $line = <INFILE>;
      @regex_result = $line =~ m/\d+/g;
      foreach(@regex_result)
      {
        if (length($_) > 0)
        {
          $face_count = $_;
        }
      }
      print " ... reading $face_count face indices ... ";
      for ($counter = 0; $counter < $face_count; $counter++)
      {
        $line = <INFILE>;
        @regex_result = $line =~ m/\d+/g;
        $n = 0;
        foreach(@regex_result)
        {
          if (length($_) > 0)
          {
            $f_id[$n] = $_;
            $n++;
          }
        }
        push(@v1_id, $f_id[0]);
        push(@v2_id, $f_id[1]);
        push(@v3_id, $f_id[2]);
        #print "$f_id[0], $f_id[1], $f_id[2]\n";
      }
      print "ok\n";
    }
    if ($line =~ m/normal_indices/g)
    {
      $line = <INFILE>;
      @regex_result = $line =~ m/\d+/g;
      foreach(@regex_result)
      {
        if (length($_) > 0)
        {
          $face_count = $_;
        }
      }
      print " ... reading $face_count normal indices ... ";
      for ($counter = 0; $counter < $face_count; $counter++)
      {
        $line = <INFILE>;
        @regex_result = $line =~ m/\d+/g;
        $n = 0;
        foreach(@regex_result)
        {
          if (length($_) > 0)
          {
            $n_id[$n] = $_;
            $n++;
          }
        }
        push(@n1_id, $n_id[0]);
        push(@n2_id, $n_id[1]);
        push(@n3_id, $n_id[2]);
        #print "$n_id[0], $n_id[1], $n_id[2]\n";
      }
      print "ok\n";
    }
    if ($line =~ m/uv_indices/g)
    {
      $line = <INFILE>;
      @regex_result = $line =~ m/\d+/g;
      foreach(@regex_result)
      {
        if (length($_) > 0)
        {
          $face_count = $_;
        }
      }
      print " ... reading $face_count texture coordinate indices ... ";
      for ($counter = 0; $counter < $face_count; $counter++)
      {
        $line = <INFILE>;
        @regex_result = $line =~ m/\d+/g;
        $n = 0;
        foreach(@regex_result)
        {
          if (length($_) > 0)
          {
            $t_id[$n] = $_;
            $n++;
          }
        }
        push(@t1_id, $t_id[0]);
        push(@t2_id, $t_id[1]);
        push(@t3_id, $t_id[2]);
        #print "$t_id[0], $t_id[1], $t_id[2]\n";
      }
      print "ok\n";
    }

  }

  close(INFILE);
}


# calculate_area()
# calculate the area of each facette and total area
sub calculate_area # void
{
  print " ... calculating surface area ... ";
  for($counter = 0; $counter < $face_count; $counter++)
  {
    # diference vectors 
    $dv1_x = $vert_x[$v1_id[$counter]] - $vert_x[$v2_id[$counter]];
    $dv1_y = $vert_y[$v1_id[$counter]] - $vert_y[$v2_id[$counter]];
    $dv1_z = $vert_z[$v1_id[$counter]] - $vert_z[$v2_id[$counter]];

    $dv2_x = $vert_x[$v3_id[$counter]] - $vert_x[$v2_id[$counter]];
    $dv2_y = $vert_y[$v3_id[$counter]] - $vert_y[$v2_id[$counter]];
    $dv2_z = $vert_z[$v3_id[$counter]] - $vert_z[$v2_id[$counter]];

    # cross product
    $cross_x = $dv1_y * $dv2_z - $dv2_y * $dv1_z;
    $cross_y = $dv2_x * $dv1_z - $dv1_x * $dv2_z;
    $cross_z = $dv1_x * $dv2_y - $dv2_x * $dv1_y;

    $area = .5 * sqrt($cross_x*$cross_x + $cross_y*$cross_y + $cross_z*$cross_z);
    push(@areas,$area);
#    print " Dreiecksflaeche = $area\n";
    $total_area += $area;
  }
  print "ok\n";
}



sub place
{
  print " ... placing ... ";
  $total_placements = 0;
  for($counter=0; $counter < $face_count; $counter++)
  {
    $area = $areas[$counter];
    $number_of_elements = $area * $approx_placements / $total_area;
    $place_for_sure = floor($number_of_elements);
    $place_maybe = $number_of_elements - $place_for_sure;
    $total_placements += $place_for_sure;
    $maybe = rand();

    # diference vectors 
    $dv1_x = $vert_x[$v1_id[$counter]] - $vert_x[$v2_id[$counter]];
    $dv1_y = $vert_y[$v1_id[$counter]] - $vert_y[$v2_id[$counter]];
    $dv1_z = $vert_z[$v1_id[$counter]] - $vert_z[$v2_id[$counter]];

    $dv2_x = $vert_x[$v3_id[$counter]] - $vert_x[$v2_id[$counter]];
    $dv2_y = $vert_y[$v3_id[$counter]] - $vert_y[$v2_id[$counter]];
    $dv2_z = $vert_z[$v3_id[$counter]] - $vert_z[$v2_id[$counter]];

    for($place_counter=0; $place_counter<$place_for_sure; $place_counter++)
    {
      do
      {
        $U = rand();
        $V = rand();
      } while(($U+$V)>1);

       $p_x = $vert_x[$v2_id[$counter]] + (($dv1_x*$U) + ($dv2_x*$V));
       $p_y = $vert_y[$v2_id[$counter]] + (($dv1_y*$U) + ($dv2_y*$V));
       $p_z = $vert_z[$v2_id[$counter]] + (($dv1_z*$U) + ($dv2_z*$V));
       push(@pv_x, $p_x);
       push(@pv_y, $p_y);
       push(@pv_z, $p_z);

       $n1_x = $norm_x[$n1_id[$counter]];
       $n1_y = $norm_y[$n1_id[$counter]];
       $n1_z = $norm_z[$n1_id[$counter]];

       $n2_x = $norm_x[$n2_id[$counter]];
       $n2_y = $norm_y[$n2_id[$counter]];
       $n2_z = $norm_z[$n2_id[$counter]];

       $n3_x = $norm_x[$n2_id[$counter]];
       $n3_y = $norm_y[$n2_id[$counter]];
       $n3_z = $norm_z[$n2_id[$counter]];

       $nu_x = (1-$U)*$n2_x + $U*$n1_x;
       $nu_y = (1-$U)*$n2_y + $U*$n1_y;
       $nu_z = (1-$U)*$n2_z + $U*$n1_z;

       $nv_x = (1-$V)*$n2_x + $V*$n3_x;
       $nv_y = (1-$V)*$n2_y + $V*$n3_y;
       $nv_z = (1-$V)*$n2_z + $V*$n3_z;

       $n_x = $nu_x + $nv_x;
       $n_y = $nu_y + $nv_y;
       $n_z = $nu_z + $nv_z;

       $nlength = sqrt(($n_x*$n_x)+($n_y*$n_y)+($n_z*$n_z));

       $n_x = $n_x / $nlength;
       $n_y = $n_y / $nlength;
       $n_z = $n_z / $nlength;

       push(@pn_x,$n_x);
       push(@pn_y,$n_y);
       push(@pn_z,$n_z);

       if ($has_texcoord == 1)
       {
          $duv1_u = $tex_u[$t1_id[$counter]]-$tex_u[$t2_id[$counter]];
          $duv1_v = $tex_v[$t1_id[$counter]]-$tex_v[$t2_id[$counter]];
          $duv2_u = $tex_u[$t3_id[$counter]]-$tex_u[$t2_id[$counter]];
          $duv2_v = $tex_v[$t3_id[$counter]]-$tex_v[$t2_id[$counter]];

          $uv_u = $tex_u[$t2_id[$counter]] + $U*$duv1_u + $V*$duv2_u;
          $uv_v = $tex_v[$t2_id[$counter]] + $U*$duv1_v + $V*$duv2_v;
          push(@puv_u, $uv_u);
          push(@puv_v, $uv_v);
       }

    }
    if($maybe <= $place_maybe)
    {
      $total_placements++;
      do
      {
        $U = rand();
	$V = rand();
      } while(($U+$V)>1);

       $p_x = $vert_x[$v2_id[$counter]] + (($dv1_x*$U) + ($dv2_x*$V));
       $p_y = $vert_y[$v2_id[$counter]] + (($dv1_y*$U) + ($dv2_y*$V));
       $p_z = $vert_z[$v2_id[$counter]] + (($dv1_z*$U) + ($dv2_z*$V));
       push(@pv_x, $p_x);
       push(@pv_y, $p_y);
       push(@pv_z, $p_z);

       $n1_x = $norm_x[$n1_id[$counter]];
       $n1_y = $norm_y[$n1_id[$counter]];
       $n1_z = $norm_z[$n1_id[$counter]];

       $n2_x = $norm_x[$n2_id[$counter]];
       $n2_y = $norm_y[$n2_id[$counter]];
       $n2_z = $norm_z[$n2_id[$counter]];

       $n3_x = $norm_x[$n2_id[$counter]];
       $n3_y = $norm_y[$n2_id[$counter]];
       $n3_z = $norm_z[$n2_id[$counter]];

       $nu_x = (1-$U)*$n2_x + $U*$n1_x;
       $nu_y = (1-$U)*$n2_y + $U*$n1_y;
       $nu_z = (1-$U)*$n2_z + $U*$n1_z;

       $nv_x = (1-$V)*$n2_x + $V*$n3_x;
       $nv_y = (1-$V)*$n2_y + $V*$n3_y;
       $nv_z = (1-$V)*$n2_z + $V*$n3_z;

       $n_x = $nu_x + $nv_x;
       $n_y = $nu_y + $nv_y;
       $n_z = $nu_z + $nv_z;

       $nlength = sqrt(($n_x*$n_x)+($n_y*$n_y)+($n_z*$n_z));

       $n_x = $n_x / $nlength;
       $n_y = $n_y / $nlength;
       $n_z = $n_z / $nlength;

       push(@pn_x,$n_x);
       push(@pn_y,$n_y);
       push(@pn_z,$n_z);

       if ($has_texcoord == 1)
       {
          $duv1_u = $tex_u[$t1_id[$counter]]-$tex_u[$t2_id[$counter]];
          $duv1_v = $tex_v[$t1_id[$counter]]-$tex_v[$t2_id[$counter]];
          $duv2_u = $tex_u[$t3_id[$counter]]-$tex_u[$t2_id[$counter]];
          $duv2_v = $tex_v[$t3_id[$counter]]-$tex_v[$t2_id[$counter]];

          $uv_u = $tex_u[$t2_id[$counter]] + $U*$duv1_u + $V*$duv2_u;
          $uv_v = $tex_v[$t2_id[$counter]] + $U*$duv1_v + $V*$duv2_v;
          push(@puv_u, $uv_u);
          push(@puv_v, $uv_v);
       }
    }
  }
  print "ok\n";
}


sub write_output
{
  @name_parts = split(/\./,$program_options{outfile});
  if ($program_options{seperate} == 0)
  {
    $outfilename = $program_options{outfile};
  }
  else
  {
    $outfilename = $name_parts[0] . "_p." . $name_parts[1];
  }
  print " ... trying to open $outfilename for writing ... ";
  open (OUTFILE,">$outfilename") || die "failed\n";
  print "ok\n";
  print " ... writing data ... ";

  print OUTFILE "#declare pom_placement_count = $total_placements;\n";
  print OUTFILE "#declare pom_positions = \n";
  print OUTFILE "array[$total_placements]\n{\n";
  for($counter=0; $counter < $total_placements; $counter++)
  {
    print OUTFILE "< $pv_x[$counter], $pv_y[$counter], $pv_z[$counter]>";
    if($counter < ($total_placements-1))
    {
      print OUTFILE ",\n";
    }
    else
    {
      print OUTFILE "\n";
    }
  }
  print OUTFILE "}\n";

  if ($program_options{seperate} == 1)
  {
    print "ok\n";
    close(OUTFILE);
    $outfilename = $name_parts[0] . "_n." . $name_parts[1];
    print " ... trying to open $outfilename for writing ... ";
    open (OUTFILE,">$outfilename") || die "failed\n";
    print "ok\n";
    print " ... writing data ... ";
    print OUTFILE "#declare pom_placement_count = $total_placements;\n";
  }

  print OUTFILE "#declare pom_normals = \n";
  print OUTFILE "array[$total_placements]\n{\n";
  for($counter=0; $counter < $total_placements; $counter++)
  {
    print OUTFILE "< $pn_x[$counter], $pn_y[$counter], $pn_z[$counter]>";
    if($counter < ($total_placements-1))
    {
      print OUTFILE ",\n";
    }
    else
    {
      print OUTFILE "\n";
    }
  }
  print OUTFILE "}\n";

  if ($has_texcoord == 1)
  {
    if ($program_options{seperate} == 1)
    {
      print "ok\n";
      close(OUTFILE);
      $outfilename = $name_parts[0] . "_uv." . $name_parts[1];
      print " ... trying to open $outfilename for writing ... ";
      open (OUTFILE,">$outfilename") || die "failed\n";
      print "ok\n";
      print " ... writing data ... ";
      print OUTFILE "#declare pom_placement_count = $total_placements;\n";
    }
    print OUTFILE "#declare pom_uvs = \n";
    print OUTFILE "array[$total_placements]\n{\n";
    for($counter=0; $counter < $total_placements; $counter++)
    {
      print OUTFILE "< $puv_u[$counter], $puv_v[$counter]>";
      if($counter < ($total_placements-1))
      {
        print OUTFILE ",\n";
      }
      else
      {
        print OUTFILE "\n";
      }
    }
    print OUTFILE "}\n";
  }


  print "ok\n"; 
  close(OUTFILE);

}

###
# MAIN
###

  # process program arguments
  read_program_arguments();

  # test if input file exist
  if (!(-e "$program_options{infile}"))
  {
    print " input file ($program_options{infile}) doesn't seems to exist ...\n";
    exit();
  }

  # parsing input file
  parse_input_file($program_options{infile});

  # calculate the area of each facette and total area
  calculate_area();

  $approx_placements = floor($program_options{density}*$total_area);
  print " ... approximately $approx_placements will be placed (density = $program_options{density})\n";

  # the essential part
  place();

  write_output();

  print " ... good bye.\n";