pocketmine\level\generator\populator\GroundFire::getHighestWorkableBlock PHP Метод

    private function getHighestWorkableBlock($x, $z)
    {
        for ($y = 0; $y <= 127; ++$y) {
            $b = $this->level->getBlockIdAt($x, $y, $z);
            if ($b == Block::AIR) {
                break;
            }
        }
        return $y === 0 ? -1 : $y;
    }