
<?


  $size=41;
  $nrd=8;

  @$x=$_REQUEST['x']+0;
  @$y=$_REQUEST['y']+0;
  @$r=$_REQUEST['r']+0;
  $r=round($r*8/360);
  //echo $r;
  
    function stepforward (&$x, &$y, $r) {
    switch ($r) {
      case 0: $y++; break;
      case 1: $x++; $y++; break;
      case 2: $x++; break;
      case 3: $x++; $y--; break;
      case 4: $y--; break;
      case 5: $x--; $y--; break;
      case 6: $x--; break;
      case 7: $x--; $y++; break;
    }
  }

  @$action=$_REQUEST['action'];
  if ($x<1)
    $x=1;
  if ($y<1)
    $y=1;
  

  if (!isset($x))
    $x=1;
  if (!isset($y))
    $y=1;
    
  if ($action=='left')
    $r--;
  if ($action=='right')
    $r++;
  if ($r<0)
    $r=$nrd-1;
  if ($r>=$nrd)
    $r=0;
  $rr=$r*360/8;
  $fx=$x;
  $fy=$y;
  

  
  if ($action=='forward') {
    //step in right direction
    stepforward ($x, $y, $r);
  };
  
  $idx=1 + ($size*($x-1)+($y-1))*$nrd + $r;
  $i="${idx}";
  while (strlen($i)<4)
    $i='0'.$i;
  $img="/images/frame${i}.jpg";
  
  $pos="&amp;x=${x}&amp;y=${y}&amp;r=${rr}";
  
  $fx=$x; $fy=$y;
  //echo "$fx $fy $r";
  stepforward ($fx,$fy, $r);
  //echo "<br>$fx $fy $r";
  $idx=1 + ($size*($fx-1)+($fy-1))*$nrd + $r;
  //echo "<br>$fx $fy $r $idx";

  $i="${idx}";
  while (strlen($i)<4)
    $i='0'.$i;
  $imgfwd="./images/frame${i}.jpg";
  //echo $imgfwd;
  if (file_exists($imgfwd))
    $urlfwd="<a href=\"?action=forward${pos}\">forward</a>";
  else
    $urlfwd='&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ';
  

?>
<html><head><title>Titan Walkround</title></head>
<body>
<a href="?action=left<?=$pos?>">left</a>
&nbsp;
<?=$urlfwd?>
&nbsp;
<a href="?action=right<?=$pos?>">right</a>
<br>
<img src="<?=$img?>">
</body>
</html>