Implement anvil fall damage (#5312)

src/block/Anvil.php

@@ -107,6 +107,14 @@ class Anvil extends Transparent implements Fallable{
 		return true;
 	}
 
+	public function getFallDamagePerBlock() : float{
+		return 2.0;
+	}
+
+	public function getMaxFallDamage() : float{
+		return 40.0;
+	}
+
 	public function getLandSound() : ?Sound{
 		return new AnvilFallSound();
 	}

src/block/utils/Fallable.php

@@ -42,6 +42,18 @@ interface Fallable{
 	 */
 	public function onHitGround(FallingBlock $blockEntity) : bool;
 
+	/**
+	 * Returns the damage caused per fallen block. This is multiplied by the fall distance (and capped according to
+	 * {@link Fallable::getMaxFallDamage()}) to calculate the damage dealt to any entities who intersect with the block
+	 * when it hits the ground.
+	 */
+	public function getFallDamagePerBlock() : float;
+
+	/**
+	 * Returns the maximum damage the block can deal to an entity when it hits the ground.
+	 */
+	public function getMaxFallDamage() : float;
+
 	/**
 	 * Returns the sound that will be played when FallingBlock hits the ground.
 	 */

src/block/utils/FallableTrait.php

@@ -64,6 +64,14 @@ trait FallableTrait{
 		return true;
 	}
 
+	public function getFallDamagePerBlock() : float{
+		return 0.0;
+	}
+
+	public function getMaxFallDamage() : float{
+		return 0.0;
+	}
+
 	public function getLandSound() : ?Sound{
 		return null;
 	}

src/entity/Living.php

@@ -73,6 +73,7 @@ use function max;
 use function min;
 use function mt_getrandmax;
 use function mt_rand;
+use function round;
 use function sqrt;
 use const M_PI;
 
@@ -429,6 +430,10 @@ abstract class Living extends Entity{
 		$source->setModifier(-$source->getFinalDamage() * min(ceil(min($totalEpf, 25) * (mt_rand(50, 100) / 100)), 20) * 0.04, EntityDamageEvent::MODIFIER_ARMOR_ENCHANTMENTS);
 
 		$source->setModifier(-min($this->getAbsorption(), $source->getFinalDamage()), EntityDamageEvent::MODIFIER_ABSORPTION);
+
+		if($cause === EntityDamageEvent::CAUSE_FALLING_BLOCK && $this->armorInventory->getHelmet() instanceof Armor){
+			$source->setModifier(-($source->getFinalDamage() / 4), EntityDamageEvent::MODIFIER_ARMOR_HELMET);
+		}
 	}
 
 	/**
@@ -460,6 +465,15 @@ abstract class Living extends Entity{
 			if($damage > 0){
 				$attacker->attack(new EntityDamageByEntityEvent($this, $attacker, EntityDamageEvent::CAUSE_MAGIC, $damage));
 			}
+
+			if($source->getModifier(EntityDamageEvent::MODIFIER_ARMOR_HELMET) < 0){
+				$helmet = $this->armorInventory->getHelmet();
+				if($helmet instanceof Armor){
+					$finalDamage = $source->getFinalDamage();
+					$this->damageItem($helmet, (int) round($finalDamage * 4 + lcg_value() * $finalDamage * 2));
+					$this->armorInventory->setHelmet($helmet);
+				}
+			}
 		}
 	}
 

src/entity/object/FallingBlock.php

@@ -30,8 +30,10 @@ use pocketmine\data\bedrock\block\BlockStateDeserializeException;
 use pocketmine\data\SavedDataLoadingException;
 use pocketmine\entity\Entity;
 use pocketmine\entity\EntitySizeInfo;
+use pocketmine\entity\Living;
 use pocketmine\entity\Location;
 use pocketmine\event\entity\EntityBlockChangeEvent;
+use pocketmine\event\entity\EntityDamageByEntityEvent;
 use pocketmine\event\entity\EntityDamageEvent;
 use pocketmine\math\Vector3;
 use pocketmine\nbt\tag\ByteTag;
@@ -44,6 +46,8 @@ use pocketmine\network\mcpe\protocol\types\entity\EntityMetadataProperties;
 use pocketmine\world\format\io\GlobalBlockStateHandlers;
 use pocketmine\world\sound\BlockBreakSound;
 use function abs;
+use function min;
+use function round;
 
 class FallingBlock extends Entity{
 	private const TAG_FALLING_BLOCK = "FallingBlock"; //TAG_Compound
@@ -156,8 +160,20 @@ class FallingBlock extends Entity{
 	}
 
 	protected function onHitGround() : ?float{
-		if($this->block instanceof Fallable && !$this->block->onHitGround($this)){
-			$this->flagForDespawn();
+		if($this->block instanceof Fallable){
+			$damagePerBlock = $this->block->getFallDamagePerBlock();
+			if($damagePerBlock > 0 && ($fallenBlocks = round($this->fallDistance) - 1) > 0){
+				$damage = min($fallenBlocks * $damagePerBlock, $this->block->getMaxFallDamage());
+				foreach($this->getWorld()->getCollidingEntities($this->getBoundingBox()) as $entity){
+					if($entity instanceof Living){
+						$ev = new EntityDamageByEntityEvent($this, $entity, EntityDamageEvent::CAUSE_FALLING_BLOCK, $damage);
+						$entity->attack($ev);
+					}
+				}
+			}
+			if(!$this->block->onHitGround($this)){
+				$this->flagForDespawn();
+			}
 		}
 		return null;
 	}

src/event/entity/EntityDamageEvent.php

@@ -46,6 +46,7 @@ class EntityDamageEvent extends EntityEvent implements Cancellable{
 	public const MODIFIER_TOTEM = 8;
 	public const MODIFIER_WEAPON_ENCHANTMENTS = 9;
 	public const MODIFIER_PREVIOUS_DAMAGE_COOLDOWN = 10;
+	public const MODIFIER_ARMOR_HELMET = 11;
 
 	public const CAUSE_CONTACT = 0;
 	public const CAUSE_ENTITY_ATTACK = 1;
@@ -63,6 +64,7 @@ class EntityDamageEvent extends EntityEvent implements Cancellable{
 	public const CAUSE_MAGIC = 13;
 	public const CAUSE_CUSTOM = 14;
 	public const CAUSE_STARVATION = 15;
+	public const CAUSE_FALLING_BLOCK = 16;
 
 	private float $baseDamage;
 	private float $originalBase;

src/event/player/PlayerDeathEvent.php

@@ -25,6 +25,7 @@ namespace pocketmine\event\player;
 
 use pocketmine\block\BlockTypeIds;
 use pocketmine\entity\Living;
+use pocketmine\entity\object\FallingBlock;
 use pocketmine\event\entity\EntityDamageByBlockEvent;
 use pocketmine\event\entity\EntityDamageByEntityEvent;
 use pocketmine\event\entity\EntityDamageEvent;
@@ -155,6 +156,19 @@ class PlayerDeathEvent extends EntityDeathEvent{
 			case EntityDamageEvent::CAUSE_MAGIC:
 				return KnownTranslationFactory::death_attack_magic($name);
 
+			case EntityDamageEvent::CAUSE_FALLING_BLOCK:
+				if($deathCause instanceof EntityDamageByEntityEvent){
+					$e = $deathCause->getDamager();
+					if($e instanceof FallingBlock){
+						if($e->getBlock()->getTypeId() === BlockTypeIds::ANVIL){
+							return KnownTranslationFactory::death_attack_anvil($name);
+						}else{
+							return KnownTranslationFactory::death_attack_fallingBlock($name);
+						}
+					}
+				}
+				break;
+
 			case EntityDamageEvent::CAUSE_CUSTOM:
 				break;