pocketmine\level\SimpleChunkManager::getBlockDataAt PHP Method

    public function getBlockDataAt(int $x, int $y, int $z) : int
    {
        if ($chunk = $this->getChunk($x >> 4, $z >> 4)) {
            return $chunk->getBlockData($x & 0xf, $y & 0x7f, $z & 0xf);
        }
        return 0;
    }