<?php
# Starcraft 2 M3 to OBJ Converter v0.1
# Currently Imports: Mesh, Texture Map
# Does Not Yet Support: Bones, Materials, Geosets, Animations
#########################
# $argv[1] is a user editable field, 
#########################
  $temp = explode(".m3", $argv[1]);
    $file = $argv[1];
    $path = $temp[0];
    echo("Exporting Model $path.m3 to $path.obj\n\n");
    $file = fopen($file, 'rb') or die("Failed to open $file!\n");
    if(fread($file,4) != "33DM") die("Failed! File is not a StarCraft 2 model!\n");
    fseek($file, 4); # find where tags start
    $index = unpack(V, fread($file, 4));
    # search for __8U "5F 5F 38 55" tag for vertex offset
    $offset = $index[1];
    while(1){
        fseek($file, $offset+16);
        $string = fread($file, 4);
        if ($string == '__8U'){
            $offset+=20;
            break;
        }
        $offset++;
    }
    fseek($file, $offset);
    $index = unpack(V, fread($file, 4));
    
    fseek($file, $offset+4);
    $maxVerts = unpack(V, fread($file, 4)); # maximum extents
    $maxVerts[1] = $maxVerts[1] + $index[1];
    
    fseek($file, $offset+32); # face data
    $indexFaces = unpack(V, fread($file, 4));
    fseek($file, $offset+36);
    $maxFaces = unpack(V, fread($file, 4));
    $maxFaces[1] = $maxFaces[1]*2 + $indexFaces[1];
  
    $i = 0;
    $offset = $index[1];
    while(1){
      if ($offset >= $maxVerts[1]) break;
      for($j=0;$j<3;$j++){ # read verts
        fseek($file, $offset);
        $temp = unpack(f, fread($file, 4));
        $vert[$i] = $temp[1];
        $offset +=4;
        $i++;
      }
      $offset+=12;
      for($j=0;$j<2;$j++){ # read UV
        fseek($file, $offset);
        $temp = unpack(v, fread($file, 2));
        $uv[$k] = $temp[1] / 2046;
        $offset +=2;
        $k++;
      }
      fseek($file, $offset); # some model files have 4 null bytes after uv, let's hope there's no more special cases
      if (fread($file,1) != "FF") $offset+=4;
      $offset+=4;
    }
    $i=0;
    $offset = $indexFaces[1];
    while(1){ # read faces
      if ($offset >= $maxFaces[1]) break;
      fseek($file, $offset);
      $temp = unpack(v, fread($file, 2));
      $face[$i]=$temp[1];
      $i++;
      $offset+=2;
    }
    $out = fopen($path . ".obj", 'w+');
    for($i=0; $i<sizeof($vert); $i+=3){
      fwrite($out, "v " . $vert[$i] . " " . $vert[$i+1] . " " . $vert[$i+2] . "\n");
    }
    for($i=0; $i<sizeof($uv); $i+=2){
      fwrite($out, "vt " . $uv[$i] . " " . $uv[$i+1] . "\n");
    }
    for($i=0; $i<sizeof($face); $i+=3){
      fwrite($out, "f " . ($face[$i]+1) . "/" . ($face[$i]+1) . " " . ($face[$i+1]+1) . "/" . ($face[$i+1]+1) . " " . ($face[$i+2]+1) . "/" . ($face[$i+2]+1) . "\n");
    }
    fclose($out);
    echo("Done!\n\n");
?>