Функция скрипт на PHP для определения попадания точки в многоугольник

class Polygon
{

protected $polygon = array();


public function PointInPoligon($arrpoint, $arrpoligonpoints)
{
$this->set_polygon($this->convert_arr($arrpoligonpoints));

return $this->calc($arrpoint);
}

public function convert_arr($points)
{
if (count($points) < 6)
return false;

$polygon = array();

foreach ($points as $key=>$point)
{
if ($key%2 == 0) ;else $polygon[] = array($points[$key-1], $points[$key ]);

}

return $polygon;
}

/**
* Polygon itself, with basic vector-based structure
* Array: [ [1,1], [2,1], [3,0], [2,-1] ]
*
* @var $polygon array
*/

public function set_polygon($polygon)
{
if (count($polygon) < 3)
return false;
if (!isset($polygon[0]['x']))
{
foreach ($polygon as &$point)
{
$point = array('x' => $point[0], 'y' => $point[1]);
}
}
$this->polygon = $polygon;
}

/**
* Check if $polygon contains $test value
*
* @var $test array(x=>decimal, y=>decimal)
*/

public function calc($test)
{
$q_patt = array(array(0, 1), array(3, 2));
$end = end($this->polygon);
$pred_pt = end($this->polygon);
$pred_pt['x'] -= $test['x'];
$pred_pt['y'] -= $test['y'];
$pred_q = $q_patt[$pred_pt['y'] < 0][$pred_pt['x'] < 0];
$w = 0;
for ($iter = reset($this->polygon); $iter !== false; $iter = next($this->
polygon))
{
$cur_pt = $iter;
$cur_pt['x'] -= $test['x'];
$cur_pt['y'] -= $test['y'];
$q = $q_patt[$cur_pt['y'] < 0][$cur_pt['x'] < 0];
switch ($q - $pred_q)
{
case - 3:
++$w;
break;
case 3:
--$w;
break;
case - 2:
if ($pred_pt['x'] * $cur_pt['y'] >= $pred_pt['y'] * $cur_pt['x'])
++$w;
break;
case 2:
if (!($pred_pt['x'] * $cur_pt['y'] >= $pred_pt['y'] * $cur_pt['x']))
--$w;
break;
}
$pred_pt = $cur_pt;
$pred_q = $q;
}

return $w != 0;
}

}

$p = new Polygon();
$good = array(
350,
180,
280,
380,
520,
350,
600,
170);

$p->PointInPoligon(array(x => 65, y =>567),$goodl)