Add support for basic entity picking via middle-click (#5397)

Support for more advanced stuff like NBT copying wasn't added in this PR, as the NBT used by PM is currently an inconsistent mess and doesn't play nice with vanilla. In the interests of avoiding this mess propagating, it's been left for another time.

Adds PlayerEntityPickEvent a la PlayerBlockPickEvent
and Entity->getPickedItem().

src/entity/Entity.php

@@ -35,6 +35,7 @@ use pocketmine\event\entity\EntityMotionEvent;
 use pocketmine\event\entity\EntityRegainHealthEvent;
 use pocketmine\event\entity\EntitySpawnEvent;
 use pocketmine\event\entity\EntityTeleportEvent;
+use pocketmine\item\Item;
 use pocketmine\math\AxisAlignedBB;
 use pocketmine\math\Facing;
 use pocketmine\math\Vector2;
@@ -1560,6 +1561,13 @@ abstract class Entity{
 		$this->hasSpawned = [];
 	}
 
+	/**
+	 * Returns the item that players will equip when middle-clicking on this entity.
+	 */
+	public function getPickedItem() : ?Item{
+		return null;
+	}
+
 	/**
 	 * Flags the entity to be removed from the world on the next tick.
 	 */

src/entity/Squid.php

@@ -26,6 +26,7 @@ namespace pocketmine\entity;
 use pocketmine\entity\animation\SquidInkCloudAnimation;
 use pocketmine\event\entity\EntityDamageByEntityEvent;
 use pocketmine\event\entity\EntityDamageEvent;
+use pocketmine\item\Item;
 use pocketmine\item\VanillaItems;
 use pocketmine\math\Vector3;
 use pocketmine\nbt\tag\CompoundTag;
@@ -124,4 +125,8 @@ class Squid extends WaterAnimal{
 			VanillaItems::INK_SAC()->setCount(mt_rand(1, 3))
 		];
 	}
+
+	public function getPickedItem() : ?Item{
+		return VanillaItems::SQUID_SPAWN_EGG();
+	}
 }

src/entity/Villager.php

@@ -23,6 +23,8 @@ declare(strict_types=1);
 
 namespace pocketmine\entity;
 
+use pocketmine\item\Item;
+use pocketmine\item\VanillaItems;
 use pocketmine\nbt\tag\CompoundTag;
 use pocketmine\network\mcpe\protocol\types\entity\EntityIds;
 use pocketmine\network\mcpe\protocol\types\entity\EntityMetadataCollection;
@@ -87,6 +89,10 @@ class Villager extends Living implements Ageable{
 		return $this->baby;
 	}
 
+	public function getPickedItem() : ?Item{
+		return VanillaItems::VILLAGER_SPAWN_EGG();
+	}
+
 	protected function syncNetworkData(EntityMetadataCollection $properties) : void{
 		parent::syncNetworkData($properties);
 		$properties->setGenericFlag(EntityMetadataFlags::BABY, $this->baby);

src/entity/Zombie.php

@@ -23,6 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\entity;
 
+use pocketmine\item\Item;
 use pocketmine\item\VanillaItems;
 use pocketmine\network\mcpe\protocol\types\entity\EntityIds;
 use function mt_rand;
@@ -65,4 +66,8 @@ class Zombie extends Living{
 		//TODO: check for equipment and whether it's a baby
 		return 5;
 	}
+
+	public function getPickedItem() : ?Item{
+		return VanillaItems::ZOMBIE_SPAWN_EGG();
+	}
 }

src/entity/object/FallingBlock.php

@@ -35,6 +35,7 @@ use pocketmine\entity\Location;
 use pocketmine\event\entity\EntityBlockChangeEvent;
 use pocketmine\event\entity\EntityDamageByEntityEvent;
 use pocketmine\event\entity\EntityDamageEvent;
+use pocketmine\item\Item;
 use pocketmine\math\Vector3;
 use pocketmine\nbt\tag\ByteTag;
 use pocketmine\nbt\tag\CompoundTag;
@@ -194,6 +195,10 @@ class FallingBlock extends Entity{
 		return $nbt;
 	}
 
+	public function getPickedItem() : ?Item{
+		return $this->block->asItem();
+	}
+
 	protected function syncNetworkData(EntityMetadataCollection $properties) : void{
 		parent::syncNetworkData($properties);
 

src/entity/object/Painting.php

@@ -28,6 +28,7 @@ use pocketmine\entity\Entity;
 use pocketmine\entity\EntitySizeInfo;
 use pocketmine\entity\Location;
 use pocketmine\event\entity\EntityDamageByEntityEvent;
+use pocketmine\item\Item;
 use pocketmine\item\VanillaItems;
 use pocketmine\math\AxisAlignedBB;
 use pocketmine\math\Facing;
@@ -165,6 +166,10 @@ class Painting extends Entity{
 		));
 	}
 
+	public function getPickedItem() : ?Item{
+		return VanillaItems::PAINTING();
+	}
+
 	/**
 	 * Returns the painting motive (which image is displayed on the painting)
 	 */

src/entity/object/PrimedTNT.php

@@ -23,11 +23,13 @@ declare(strict_types=1);
 
 namespace pocketmine\entity\object;
 
+use pocketmine\block\VanillaBlocks;
 use pocketmine\entity\Entity;
 use pocketmine\entity\EntitySizeInfo;
 use pocketmine\entity\Explosive;
 use pocketmine\event\entity\EntityDamageEvent;
 use pocketmine\event\entity\EntityPreExplodeEvent;
+use pocketmine\item\Item;
 use pocketmine\math\Vector3;
 use pocketmine\nbt\tag\CompoundTag;
 use pocketmine\network\mcpe\protocol\types\entity\EntityIds;
@@ -127,6 +129,10 @@ class PrimedTNT extends Entity implements Explosive{
 		}
 	}
 
+	public function getPickedItem() : ?Item{
+		return VanillaBlocks::TNT()->setWorksUnderwater($this->worksUnderwater)->asItem();
+	}
+
 	protected function syncNetworkData(EntityMetadataCollection $properties) : void{
 		parent::syncNetworkData($properties);