public static function areTwoVectorHaveSameDirection($line1, $line2) { $mx1 = Constant::sign($line1->point1->x - $line1->point2->x); $mx2 = Constant::sign($line2->point1->x - $line2->point2->x); $my1 = Constant::sign($line1->point1->y - $line1->point2->y); $my2 = Constant::sign($line2->point1->y - $line2->point2->y); $mz1 = Constant::sign($line1->point1->z - $line1->point2->z); $mz2 = Constant::sign($line2->point1->z - $line2->point2->z); if ($mx1 * $mx2 >= 0 && $my1 * $my2 >= 0 && $mz1 * $mz2 >= 0) { return TRUE; } return FALSE; }