Implemented Splash Potions

src/pocketmine/entity/projectile/SplashPotion.php

@@ -0,0 +1,154 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\entity\projectile;
+
+use pocketmine\entity\EffectInstance;
+use pocketmine\entity\Living;
+use pocketmine\event\entity\ProjectileHitEntityEvent;
+use pocketmine\event\entity\ProjectileHitEvent;
+use pocketmine\item\Potion;
+use pocketmine\network\mcpe\protocol\LevelEventPacket;
+use pocketmine\network\mcpe\protocol\LevelSoundEventPacket;
+use pocketmine\utils\Color;
+
+class SplashPotion extends Throwable{
+
+	public const NETWORK_ID = self::SPLASH_POTION;
+
+	protected $gravity = 0.05;
+	protected $drag = 0.01;
+
+	protected function initEntity(){
+		parent::initEntity();
+
+		$this->setPotionId($this->namedtag->getShort("PotionId", 0));
+	}
+
+	public function saveNBT(){
+		parent::saveNBT();
+		$this->namedtag->setShort("PotionId", $this->getPotionId());
+	}
+
+	public function getResultDamage() : int{
+		return -1; //no damage
+	}
+
+	protected function onHit(ProjectileHitEvent $event) : void{
+		$effects = $this->getPotionEffects();
+		$hasEffects = true;
+
+		if(empty($effects)){
+			$colors = [
+				new Color(0x38, 0x5d, 0xc6) //Default colour for splash water bottle and similar with no effects.
+			];
+			$hasEffects = false;
+		}else{
+			$colors = [];
+			foreach($effects as $effect){
+				$level = $effect->getEffectLevel();
+				for($j = 0; $j < $level; ++$j){
+					$colors[] = $effect->getColor();
+				}
+			}
+		}
+
+		$this->level->broadcastLevelEvent($this, LevelEventPacket::EVENT_PARTICLE_SPLASH, Color::mix(...$colors)->toARGB());
+		$this->level->broadcastLevelSoundEvent($this, LevelSoundEventPacket::SOUND_GLASS);
+
+		if($hasEffects){
+			if(!$this->willLinger()){
+				foreach($this->level->getNearbyEntities($this->boundingBox->grow(4.125, 2.125, 4.125), $this) as $entity){
+					if($entity instanceof Living){
+						$distanceSquared = $entity->distanceSquared($this);
+						if($distanceSquared > 16){ //4 blocks
+							continue;
+						}
+
+						$distanceMultiplier = 1 - (sqrt($distanceSquared) / 4);
+						if($event instanceof ProjectileHitEntityEvent and $entity === $event->getEntityHit()){
+							$distanceMultiplier = 1.0;
+						}
+
+						foreach($this->getPotionEffects() as $effect){
+							//getPotionEffects() is used to get COPIES to avoid accidentally modifying the same effect instance already applied to another entity
+
+							if(!$effect->getType()->isInstantEffect()){
+								$newDuration = (int) round($effect->getDuration() * 0.75 * $distanceMultiplier);
+								if($newDuration < 20){
+									continue;
+								}
+								$effect->setDuration($newDuration);
+								$entity->addEffect($effect);
+							}else{
+								$effect->getType()->applyEffect($entity, $effect, $distanceMultiplier);
+							}
+						}
+					}
+				}
+			}else{
+				//TODO: lingering potions
+			}
+		}
+
+		$this->flagForDespawn();
+	}
+
+	/**
+	 * Returns the meta value of the potion item that this splash potion corresponds to. This decides what effects will be applied to the entity when it collides with its target.
+	 * @return int
+	 */
+	public function getPotionId() : int{
+		return $this->propertyManager->getShort(self::DATA_POTION_AUX_VALUE) ?? 0;
+	}
+
+	/**
+	 * @param int $id
+	 */
+	public function setPotionId(int $id) : void{
+		$this->propertyManager->setShort(self::DATA_POTION_AUX_VALUE, $id);
+	}
+
+	/**
+	 * Returns whether this splash potion will create an area-effect cloud when it lands.
+	 * @return bool
+	 */
+	public function willLinger() : bool{
+		return $this->getDataFlag(self::DATA_FLAGS, self::DATA_FLAG_LINGER);
+	}
+
+	/**
+	 * Sets whether this splash potion will create an area-effect-cloud when it lands.
+	 * @param bool $value
+	 */
+	public function setLinger(bool $value = true) : void{
+		$this->setDataFlag(self::DATA_FLAGS, self::DATA_FLAG_LINGER, $value);
+	}
+
+	/**
+	 * @return EffectInstance[]
+	 */
+	public function getPotionEffects() : array{
+		return Potion::getPotionEffectsById($this->getPotionId());
+	}
+}