pocketmine\level\format\generic\BaseFullChunk::setBiomeColor PHP Method

    public function setBiomeColor($x, $z, $R, $G, $B)
    {
        $this->hasChanged = true;
        $this->biomeColors[($z << 4) + $x] = $this->biomeColors[($z << 4) + $x] & 0xff000000 | ($R & 0xff) << 16 | ($G & 0xff) << 8 | $B & 0xff;
    }