function Find($NodeStart, $NodeEnd)
{
$Queue = new PriorityQueue();
// Open Nodes ordered based on F cost
$Queue->setExtractFlags(PriorityQueue::EXTR_DATA);
$Closed = 0;
$Found = FALSE;
$this->Debug = '';
$this->Cache = array($NodeStart => array('G' => 0, 'F' => 0, 'Parent' => $NodeStart, 'Status' => STATUS_OPEN));
$Queue->insert($NodeStart, $this->Cache[$NodeStart]['F']);
while (!$Queue->isEmpty()) {
$Node = $Queue->extract();
if ($this->Cache[$Node]['Status'] == STATUS_CLOSED) {
continue;
}
if ($Node == $NodeEnd) {
$this->Cache[$Node]['Status'] = STATUS_CLOSED;
$Found = TRUE;
break;
}
if ($Closed > $this->Limit) {
$this->Debug = 'Hit limit. (' . $this->Limit . ')';
return NULL;
}
$Neighbours = $this->Graph->Neighbours($Node);
foreach ($Neighbours as $Neighbour) {
$G = $this->Cache[$Node]['G'] + $this->Graph->G($Node, $Neighbour);
if (isset($this->Cache[$Neighbour]) && $this->Cache[$Neighbour]['Status'] && $this->Cache[$Neighbour]['G'] <= $G) {
continue;
}
$F = $G + $this->Graph->H($Neighbour, $NodeEnd);
$this->Cache[$Neighbour] = array('G' => $G, 'F' => $F, 'Parent' => $Node, 'Status' => STATUS_OPEN);
$Queue->insert($Neighbour, $F);
}
++$Closed;
$this->Cache[$Node]['Status'] = STATUS_CLOSED;
}
if ($Found) {
$Path = array();
$Node = $NodeEnd;
while ($NodeStart != $Node) {
$Path[] = $Node;
$Node = $this->Cache[$Node]['Parent'];
}
$Path[] = $Node;
return array_reverse($Path);
}
$this->Debug = 'Path not found, ran out of open nodes.';
return NULL;
}