pocketmine\level\Level::generateChunk PHP Method

    public function generateChunk(int $x, int $z, bool $force = false)
    {
        if (count($this->chunkGenerationQueue) >= $this->chunkGenerationQueueSize and !$force) {
            return;
        }
        if (!isset($this->chunkGenerationQueue[$index = Level::chunkHash($x, $z)])) {
            Timings::$generationTimer->startTiming();
            $this->chunkGenerationQueue[$index] = true;
            $task = new GenerationTask($this, $this->getChunk($x, $z, true));
            $this->server->getScheduler()->scheduleAsyncTask($task);
            Timings::$generationTimer->stopTiming();
        }
    }

 /**
  * Generates a new level if it does not exists
  *
  * @param string $name
  * @param int    $seed
  * @param string $generator Class name that extends pocketmine\level\generator\Generator
  * @param array  $options
  *
  * @return bool
  */
 public function generateLevel($name, $seed = null, $generator = null, $options = [])
 {
     if (trim($name) === "" or $this->isLevelGenerated($name)) {
         return false;
     }
     $seed = $seed === null ? PHP_INT_SIZE === 8 ? unpack("N", @Utils::getRandomBytes(4, false))[1] << 32 >> 32 : unpack("N", @Utils::getRandomBytes(4, false))[1] : (int) $seed;
     if ($generator !== null and class_exists($generator) and is_subclass_of($generator, Generator::class)) {
         $generator = new $generator($options);
     } else {
         $options["preset"] = $this->getConfigString("generator-settings", "");
         $generator = Generator::getGenerator($this->getLevelType());
     }
     if (($provider = LevelProviderManager::getProviderByName($providerName = $this->getProperty("level-settings.default-format", "mcregion"))) === null) {
         $provider = LevelProviderManager::getProviderByName($providerName = "mcregion");
     }
     try {
         $path = $this->getDataPath() . "worlds/" . $name . "/";
         /** @var \pocketmine\level\format\LevelProvider $provider */
         $provider::generate($path, $name, $seed, $generator, $options);
         $level = new Level($this, $name, $path, $provider);
         $this->levels[$level->getId()] = $level;
         $level->initLevel();
     } catch (\Exception $e) {
         $this->logger->error("Could not generate level \"" . $name . "\": " . $e->getMessage());
         if ($this->logger instanceof MainLogger) {
             $this->logger->logException($e);
         }
         return false;
     }
     $this->getPluginManager()->callEvent(new LevelInitEvent($level));
     $this->getPluginManager()->callEvent(new LevelLoadEvent($level));
     $this->getLogger()->notice("Spawn terrain for level \"{$name}\" is being generated in the background");
     $centerX = $level->getSpawnLocation()->getX() >> 4;
     $centerZ = $level->getSpawnLocation()->getZ() >> 4;
     $order = [];
     for ($X = -4; $X <= 4; ++$X) {
         for ($Z = -4; $Z <= 4; ++$Z) {
             $distance = $X ** 2 + $Z ** 2;
             $chunkX = $X + $centerX;
             $chunkZ = $Z + $centerZ;
             $index = PHP_INT_SIZE === 8 ? ($chunkX & 0xffffffff) << 32 | $chunkZ & 0xffffffff : $chunkX . ":" . $chunkZ;
             $order[$index] = $distance;
         }
     }
     asort($order);
     $chunkX = $chunkZ = null;
     foreach ($order as $index => $distance) {
         if (PHP_INT_SIZE === 8) {
             $chunkX = $index >> 32 << 32 >> 32;
             $chunkZ = ($index & 0xffffffff) << 32 >> 32;
         } else {
             list($chunkX, $chunkZ) = explode(":", $index);
             $chunkX = (int) $chunkX;
             $chunkZ = (int) $chunkZ;
         }
         $level->generateChunk($chunkX, $chunkZ, true);
     }
     return true;
 }