ExperienceOrb.php

<?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\object;
 
use pocketmine\entity\Entity;
use pocketmine\entity\EntitySizeInfo;
use pocketmine\entity\Human;
use pocketmine\entity\Location;
use pocketmine\nbt\tag\CompoundTag;
use pocketmine\network\mcpe\protocol\types\entity\EntityIds;
use pocketmine\network\mcpe\protocol\types\entity\EntityMetadataCollection;
use pocketmine\network\mcpe\protocol\types\entity\EntityMetadataProperties;
use pocketmine\player\Player;
use function max;
use function sqrt;
 
class ExperienceOrb extends Entity{
 
    public static function getNetworkTypeId() : string{ return EntityIds::XP_ORB; }
 
    public const TAG_VALUE_PC = "Value"; //short
    public const TAG_VALUE_PE = "experience value"; //int (WTF?)
    private const TAG_AGE = "Age"; //TAG_Short
 
    public const MAX_TARGET_DISTANCE = 8.0;
 
    public const ORB_SPLIT_SIZES = [2477, 1237, 617, 307, 149, 73, 37, 17, 7, 3, 1]; //This is indexed biggest to smallest so that we can return as soon as we found the biggest value.
 
    public const DEFAULT_DESPAWN_DELAY = 6000;
    public const NEVER_DESPAWN = -1;
    public const MAX_DESPAWN_DELAY = 32767 + self::DEFAULT_DESPAWN_DELAY; //max value storable by mojang NBT :(
 
    public static function getMaxOrbSize(int $amount) : int{
        foreach(self::ORB_SPLIT_SIZES as $split){
            if($amount >= $split){
                return $split;
            }
        }
 
        return 1;
    }
 
    public static function splitIntoOrbSizes(int $amount) : array{
        $result = [];
 
        while($amount > 0){
            $size = self::getMaxOrbSize($amount);
            $result[] = $size;
            $amount -= $size;
        }
 
        return $result;
    }
 
    protected int $lookForTargetTime = 0;
 
    protected ?int $targetPlayerRuntimeId = null;
 
    protected int $xpValue;
 
    private int $despawnDelay = self::DEFAULT_DESPAWN_DELAY;
 
    public function __construct(Location $location, int $xpValue, ?CompoundTag $nbt = null){
        $this->xpValue = $xpValue;
        parent::__construct($location, $nbt);
    }
 
    protected function getInitialSizeInfo() : EntitySizeInfo{ return new EntitySizeInfo(0.25, 0.25); }
 
    protected function getInitialDragMultiplier() : float{ return 0.02; }
 
    protected function getInitialGravity() : float{ return 0.04; }
 
    protected function initEntity(CompoundTag $nbt) : void{
        parent::initEntity($nbt);
 
        $age = $nbt->getShort(self::TAG_AGE, 0);
        if($age === -32768){
            $this->despawnDelay = self::NEVER_DESPAWN;
        }else{
            $this->despawnDelay = max(0, self::DEFAULT_DESPAWN_DELAY - $age);
        }
    }
 
    public function saveNBT() : CompoundTag{
        $nbt = parent::saveNBT();
 
        if($this->despawnDelay === self::NEVER_DESPAWN){
            $age = -32768;
        }else{
            $age = self::DEFAULT_DESPAWN_DELAY - $this->despawnDelay;
        }
        $nbt->setShort(self::TAG_AGE, $age);
 
        $nbt->setShort(self::TAG_VALUE_PC, $this->getXpValue());
        $nbt->setInt(self::TAG_VALUE_PE, $this->getXpValue());
 
        return $nbt;
    }
 
    public function getDespawnDelay() : int{ return $this->despawnDelay; }
 
    public function setDespawnDelay(int $despawnDelay) : void{
        if(($despawnDelay < 0 || $despawnDelay > self::MAX_DESPAWN_DELAY) && $despawnDelay !== self::NEVER_DESPAWN){
            throw new \InvalidArgumentException("Despawn ticker must be in range 0 ... " . self::MAX_DESPAWN_DELAY . " or " . self::NEVER_DESPAWN . ", got $despawnDelay");
        }
        $this->despawnDelay = $despawnDelay;
    }
 
    public function getXpValue() : int{
        return $this->xpValue;
    }
 
    public function setXpValue(int $amount) : void{
        if($amount <= 0){
            throw new \InvalidArgumentException("XP amount must be greater than 0, got $amount");
        }
        $this->xpValue = $amount;
        $this->networkPropertiesDirty = true;
    }
 
    public function hasTargetPlayer() : bool{
        return $this->targetPlayerRuntimeId !== null;
    }
 
    public function getTargetPlayer() : ?Human{
        if($this->targetPlayerRuntimeId === null){
            return null;
        }
 
        $entity = $this->getWorld()->getEntity($this->targetPlayerRuntimeId);
        if($entity instanceof Human){
            return $entity;
        }
 
        return null;
    }
 
    public function setTargetPlayer(?Human $player) : void{
        $this->targetPlayerRuntimeId = $player !== null ? $player->getId() : null;
    }
 
    protected function entityBaseTick(int $tickDiff = 1) : bool{
        $hasUpdate = parent::entityBaseTick($tickDiff);
 
        $this->despawnDelay -= $tickDiff;
        if($this->despawnDelay <= 0){
            $this->flagForDespawn();
            return true;
        }
 
        $currentTarget = $this->getTargetPlayer();
        if($currentTarget !== null && (!$currentTarget->isAlive() || !$currentTarget->getXpManager()->canAttractXpOrbs() || $currentTarget->location->distanceSquared($this->location) > self::MAX_TARGET_DISTANCE ** 2)){
            $currentTarget = null;
        }
 
        if($this->lookForTargetTime >= 20){
            if($currentTarget === null){
                $newTarget = $this->getWorld()->getNearestEntity($this->location, self::MAX_TARGET_DISTANCE, Human::class);
 
                if($newTarget instanceof Human && !($newTarget instanceof Player && $newTarget->isSpectator()) && $newTarget->getXpManager()->canAttractXpOrbs()){
                    $currentTarget = $newTarget;
                }
            }
 
            $this->lookForTargetTime = 0;
        }else{
            $this->lookForTargetTime += $tickDiff;
        }
 
        $this->setTargetPlayer($currentTarget);
 
        if($currentTarget !== null){
            $vector = $currentTarget->getPosition()->add(0, $currentTarget->getEyeHeight() / 2, 0)->subtractVector($this->location)->divide(self::MAX_TARGET_DISTANCE);
 
            $distance = $vector->lengthSquared();
            if($distance < 1){
                $this->motion = $this->motion->addVector($vector->normalize()->multiply(0.2 * (1 - sqrt($distance)) ** 2));
            }
 
            if($currentTarget->getXpManager()->canPickupXp() && $this->boundingBox->intersectsWith($currentTarget->getBoundingBox())){
                $this->flagForDespawn();
 
                $currentTarget->getXpManager()->onPickupXp($this->getXpValue());
            }
        }
 
        return $hasUpdate;
    }
 
    protected function tryChangeMovement() : void{
        $this->checkObstruction($this->location->x, $this->location->y, $this->location->z);
        parent::tryChangeMovement();
    }
 
    public function canBeCollidedWith() : bool{
        return false;
    }
 
    protected function syncNetworkData(EntityMetadataCollection $properties) : void{
        parent::syncNetworkData($properties);
 
        $properties->setInt(EntityMetadataProperties::EXPERIENCE_VALUE, $this->xpValue);
    }
}