Projectile.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\projectile;
 
use pocketmine\block\Block;
use pocketmine\data\SavedDataLoadingException;
use pocketmine\entity\Entity;
use pocketmine\entity\Living;
use pocketmine\entity\Location;
use pocketmine\entity\object\EndCrystal;
use pocketmine\event\entity\EntityCombustByEntityEvent;
use pocketmine\event\entity\EntityDamageByChildEntityEvent;
use pocketmine\event\entity\EntityDamageByEntityEvent;
use pocketmine\event\entity\EntityDamageEvent;
use pocketmine\event\entity\ProjectileHitBlockEvent;
use pocketmine\event\entity\ProjectileHitEntityEvent;
use pocketmine\event\entity\ProjectileHitEvent;
use pocketmine\math\RayTraceResult;
use pocketmine\math\Vector3;
use pocketmine\math\VoxelRayTrace;
use pocketmine\nbt\tag\CompoundTag;
use pocketmine\nbt\tag\IntTag;
use pocketmine\nbt\tag\ListTag;
use pocketmine\timings\Timings;
use function atan2;
use function ceil;
use function count;
use function sqrt;
use const M_PI;
use const PHP_INT_MAX;
 
abstract class Projectile extends Entity{
    private const TAG_STUCK_ON_BLOCK_POS = "StuckToBlockPos";
    private const TAG_DAMAGE = "damage"; //TAG_Double
    private const TAG_TILE_X = "tileX"; //TAG_Int
    private const TAG_TILE_Y = "tileY"; //TAG_Int
    private const TAG_TILE_Z = "tileZ"; //TAG_Int
 
    protected float $damage = 0.0;
    protected ?Vector3 $blockHit = null;
 
    public function __construct(Location $location, ?Entity $shootingEntity, ?CompoundTag $nbt = null){
        parent::__construct($location, $nbt);
        if($shootingEntity !== null){
            $this->setOwningEntity($shootingEntity);
        }
    }
 
    public function attack(EntityDamageEvent $source) : void{
        if($source->getCause() === EntityDamageEvent::CAUSE_VOID){
            parent::attack($source);
        }
    }
 
    protected function initEntity(CompoundTag $nbt) : void{
        parent::initEntity($nbt);
 
        $this->setMaxHealth(1);
        $this->setHealth(1);
        $this->damage = $nbt->getDouble(self::TAG_DAMAGE, $this->damage);
 
        if(($stuckOnBlockPosTag = $nbt->getListTag(self::TAG_STUCK_ON_BLOCK_POS, IntTag::class)) !== null){
            if(count($stuckOnBlockPosTag) !== 3){
                throw new SavedDataLoadingException(self::TAG_STUCK_ON_BLOCK_POS . " tag should be a list of 3 TAG_Int");
            }
 
            $values = $stuckOnBlockPosTag->getValue();
 
            $this->blockHit = new Vector3($values[0]->getValue(), $values[1]->getValue(), $values[2]->getValue());
        }elseif(($tileXTag = $nbt->getTag(self::TAG_TILE_X)) instanceof IntTag && ($tileYTag = $nbt->getTag(self::TAG_TILE_Y)) instanceof IntTag && ($tileZTag = $nbt->getTag(self::TAG_TILE_Z)) instanceof IntTag){
            $this->blockHit = new Vector3($tileXTag->getValue(), $tileYTag->getValue(), $tileZTag->getValue());
        }
    }
 
    public function canCollideWith(Entity $entity) : bool{
        return ($entity instanceof Living || $entity instanceof EndCrystal) && !$this->onGround;
    }
 
    public function canBeCollidedWith() : bool{
        return false;
    }
 
    public function getBaseDamage() : float{
        return $this->damage;
    }
 
    public function setBaseDamage(float $damage) : void{
        $this->damage = $damage;
    }
 
    public function getResultDamage() : int{
        return (int) ceil($this->damage);
    }
 
    public function saveNBT() : CompoundTag{
        $nbt = parent::saveNBT();
 
        $nbt->setDouble(self::TAG_DAMAGE, $this->damage);
 
        if($this->blockHit !== null){
            $nbt->setTag(self::TAG_STUCK_ON_BLOCK_POS, new ListTag([
                new IntTag($this->blockHit->getFloorX()),
                new IntTag($this->blockHit->getFloorY()),
                new IntTag($this->blockHit->getFloorZ())
            ]));
        }
 
        return $nbt;
    }
 
    protected function applyDragBeforeGravity() : bool{
        return true;
    }
 
    public function onNearbyBlockChange() : void{
        if($this->blockHit !== null && $this->getWorld()->isInLoadedTerrain($this->blockHit)){
            $blockHit = $this->getWorld()->getBlock($this->blockHit);
            if(!$blockHit->collidesWithBB($this->getBoundingBox()->expandedCopy(0.001, 0.001, 0.001))){
                $this->blockHit = null;
            }
        }
 
        parent::onNearbyBlockChange();
    }
 
    public function hasMovementUpdate() : bool{
        return $this->blockHit === null && parent::hasMovementUpdate();
    }
 
    protected function move(float $dx, float $dy, float $dz) : void{
        $this->blocksAround = null;
 
        Timings::$projectileMove->startTiming();
        Timings::$projectileMoveRayTrace->startTiming();
 
        $start = $this->location->asVector3();
        $end = $start->add($dx, $dy, $dz);
 
        $hitResult = null;
 
        $world = $this->getWorld();
        foreach(VoxelRayTrace::betweenPoints($start, $end) as $vector3){
            $block = $world->getBlockAt($vector3->x, $vector3->y, $vector3->z);
 
            $blockHitResult = $this->calculateInterceptWithBlock($block, $start, $end);
            if($blockHitResult !== null){
                $end = $blockHitResult->hitVector;
                $hitResult = [$block, $blockHitResult];
                break;
            }
        }
 
        $entityDistance = PHP_INT_MAX;
 
        $newDiff = $end->subtractVector($start);
        foreach($world->getCollidingEntities($this->boundingBox->addCoord($newDiff->x, $newDiff->y, $newDiff->z)->expandedCopy(1, 1, 1), $this) as $entity){
            if($entity->getId() === $this->getOwningEntityId() && $this->ticksLived < 5){
                continue;
            }
 
            $entityBB = $entity->boundingBox->expandedCopy(0.3, 0.3, 0.3);
            $entityHitResult = $entityBB->calculateIntercept($start, $end);
 
            if($entityHitResult === null){
                continue;
            }
 
            $distance = $this->location->distanceSquared($entityHitResult->hitVector);
 
            if($distance < $entityDistance){
                $entityDistance = $distance;
                $hitResult = [$entity, $entityHitResult];
                $end = $entityHitResult->hitVector;
            }
        }
 
        Timings::$projectileMoveRayTrace->stopTiming();
 
        $this->location = Location::fromObject(
            $end,
            $this->location->world,
            $this->location->yaw,
            $this->location->pitch
        );
        $this->recalculateBoundingBox();
 
        if($hitResult !== null){
            [$objectHit, $rayTraceResult] = $hitResult;
            if($objectHit instanceof Entity){
                $ev = new ProjectileHitEntityEvent($this, $rayTraceResult, $objectHit);
                $specificHitFunc = fn() => $this->onHitEntity($objectHit, $rayTraceResult);
            }else{
                $ev = new ProjectileHitBlockEvent($this, $rayTraceResult, $objectHit);
                $specificHitFunc = fn() => $this->onHitBlock($objectHit, $rayTraceResult);
            }
 
            $motionBeforeOnHit = clone $this->motion;
            $ev->call();
            $this->onHit($ev);
            $specificHitFunc();
 
            $this->isCollided = $this->onGround = true;
            if($motionBeforeOnHit->equals($this->motion)){
                $this->motion = Vector3::zero();
            }
        }else{
            $this->isCollided = $this->onGround = false;
            $this->blockHit = null;
 
            //recompute angles...
            $f = sqrt(($this->motion->x ** 2) + ($this->motion->z ** 2));
            $this->setRotation(
                atan2($this->motion->x, $this->motion->z) * 180 / M_PI,
                atan2($this->motion->y, $f) * 180 / M_PI
            );
        }
 
        $world->onEntityMoved($this);
        $this->checkBlockIntersections();
 
        Timings::$projectileMove->stopTiming();
    }
 
    protected function calculateInterceptWithBlock(Block $block, Vector3 $start, Vector3 $end) : ?RayTraceResult{
        return $block->calculateIntercept($start, $end);
    }
 
    protected function onHit(ProjectileHitEvent $event) : void{
 
    }
 
    protected function onHitEntity(Entity $entityHit, RayTraceResult $hitResult) : void{
        $damage = $this->getResultDamage();
 
        if($damage >= 0){
            $owner = $this->getOwningEntity();
            if($owner === null){
                $ev = new EntityDamageByEntityEvent($this, $entityHit, EntityDamageEvent::CAUSE_PROJECTILE, $damage);
            }else{
                $ev = new EntityDamageByChildEntityEvent($owner, $this, $entityHit, EntityDamageEvent::CAUSE_PROJECTILE, $damage);
            }
 
            $entityHit->attack($ev);
 
            if($this->isOnFire()){
                $ev = new EntityCombustByEntityEvent($this, $entityHit, 5);
                $ev->call();
                if(!$ev->isCancelled()){
                    $entityHit->setOnFire($ev->getDuration());
                }
            }
        }
 
        if($this->despawnsOnEntityHit()){
            $this->flagForDespawn();
        }
    }
 
    protected function onHitBlock(Block $blockHit, RayTraceResult $hitResult) : void{
        $this->blockHit = $blockHit->getPosition()->asVector3();
        $blockHit->onProjectileHit($this, $hitResult);
    }
 
    protected function despawnsOnEntityHit() : bool{
        return true;
    }
}