pocketmine\level\generator\object\BigTree::getRoughLayerSize PHP Метод

    private function getRoughLayerSize(int $layer) : float
    {
        $halfHeight = $this->totalHeight / 2;
        if ($layer < $this->totalHeight / 3) {
            return -1;
        } elseif ($layer == $halfHeight) {
            return $halfHeight / 4;
        } elseif ($layer >= $this->totalHeight or $layer <= 0) {
            return 0;
        } else {
            return sqrt($halfHeight * $halfHeight - ($layer - $halfHeight) * ($layer - $halfHeight)) / 2;
        }
    }