New way to spawn entities/tiles using a global register table, allow overriding default entity/tile classes via classes

src/pocketmine/entity/Entity.php

@@ -62,9 +62,12 @@ use pocketmine\Server;
 
 abstract class Entity extends Location implements Metadatable{
 
+
 	const NETWORK_ID = -1;
 
 	public static $entityCount = 1;
+	/** @var Entity[] */
+	private static $knownEntities = [];
 
 	/**
 	 * @var Player[]
@@ -219,6 +222,39 @@ abstract class Entity extends Location implements Metadatable{
 
 	}
 
+	/**
+	 * @param int|string $type
+	 * @param FullChunk  $chunk
+	 * @param Compound   $nbt
+	 * @param            $args
+	 *
+	 * @return Entity
+	 */
+	public static function createEntity($type, FullChunk $chunk, Compound $nbt, ...$args){
+		if(isset(self::$knownEntities[$type])){
+			$class = self::$knownEntities[$type];
+			return new $class($chunk, $nbt, ...$args);
+		}
+
+		return null;
+	}
+
+	public static function registerEntity($className, $force = false){
+		$class = new \ReflectionClass($className);
+		if(is_a($className, Entity::class, true) and !$class->isAbstract()){
+			if($className::NETWORK_ID !== -1){
+				self::$knownEntities[$className::NETWORK_ID] = $className;
+			}elseif(!$force){
+				return false;
+			}
+
+			self::$knownEntities[$class->getShortName()] = $className;
+			return true;
+		}
+
+		return false;
+	}
+
 	public function saveNBT(){
 		$this->namedtag->Pos = new Enum("Pos", [
 			new Double(0, $this->x),

src/pocketmine/entity/FallingSand.php

@@ -35,8 +35,7 @@ use pocketmine\network\protocol\AddEntityPacket;
 use pocketmine\network\protocol\SetEntityMotionPacket;
 use pocketmine\Player;
 
-class FallingBlock extends Entity{
-
+class FallingSand extends Entity{
 	const NETWORK_ID = 66;
 
 	public $width = 0.98;
@@ -54,8 +53,7 @@ class FallingBlock extends Entity{
 		$this->namedtag->id = new String("id", "FallingSand");
 		if(isset($this->namedtag->TileID)){
 			$this->blockId = $this->namedtag["TileID"];
-		}
-		elseif(isset($this->namedtag->Tile)){
+		}elseif(isset($this->namedtag->Tile)){
 			$this->blockId = $this->namedtag["Tile"];
 			$this->namedtag["TileID"] = new Int("TileID", $this->blockId);
 		}
@@ -151,7 +149,7 @@ class FallingBlock extends Entity{
 
 	public function spawnTo(Player $player){
 		$pk = AddEntityPacket::getFromPool();
-		$pk->type = FallingBlock::NETWORK_ID;
+		$pk->type = FallingSand::NETWORK_ID;
 		$pk->eid = $this->getID();
 		$pk->x = $this->x;
 		$pk->y = $this->y;

src/pocketmine/entity/Item.php

@@ -25,7 +25,7 @@ use pocketmine\event\entity\EntityDamageEvent;
 use pocketmine\event\entity\EntityRegainHealthEvent;
 use pocketmine\event\entity\ItemDespawnEvent;
 use pocketmine\event\entity\ItemSpawnEvent;
-use pocketmine\item\Item;
+use pocketmine\item\Item as ItemItem;
 use pocketmine\math\Vector3;
 use pocketmine\nbt\tag\Byte;
 use pocketmine\nbt\tag\Compound;
@@ -35,12 +35,13 @@ use pocketmine\network\protocol\AddItemEntityPacket;
 use pocketmine\network\protocol\SetEntityMotionPacket;
 use pocketmine\Player;
 
-class DroppedItem extends Entity{
+class Item extends Entity{
+	const NETWORK_ID = 64;
 
 	protected $owner = null;
 	protected $thrower = null;
 	protected $pickupDelay = 0;
-	/** @var Item */
+	/** @var ItemItem */
 	protected $item;
 
 	public $width = 0.25;
@@ -67,7 +68,7 @@ class DroppedItem extends Entity{
 		if(isset($this->namedtag->Thrower)){
 			$this->thrower = $this->namedtag["Thrower"];
 		}
-		$this->item = Item::get($this->namedtag->Item["id"], $this->namedtag->Item["Damage"], $this->namedtag->Item["Count"]);
+		$this->item = ItemItem::get($this->namedtag->Item["id"], $this->namedtag->Item["Damage"], $this->namedtag->Item["Count"]);
 
 
 		$this->server->getPluginManager()->callEvent(ItemSpawnEvent::createEvent($this));
@@ -166,7 +167,7 @@ class DroppedItem extends Entity{
 	}
 
 	/**
-	 * @return Item
+	 * @return ItemItem
 	 */
 	public function getItem(){
 		return $this->item;