Implemented server-side block-break FX handling, closes #3485

this had been planned for a long time already, just never finished.
It's not fully done, because there needs to be synchronization of block-break handlers between different players attempting to break the same block, but this should resolve a lot of the bugs that previously existed, while also opening the doors to making the logic more flexible.

src/player/SurvivalBlockBreakHandler.php

@@ -0,0 +1,142 @@
+<?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\player;
+
+use pocketmine\block\Block;
+use pocketmine\entity\animation\ArmSwingAnimation;
+use pocketmine\math\Facing;
+use pocketmine\math\Vector3;
+use pocketmine\network\mcpe\protocol\LevelEventPacket;
+use pocketmine\world\particle\BlockPunchParticle;
+use pocketmine\world\sound\BlockPunchSound;
+use function abs;
+
+final class SurvivalBlockBreakHandler{
+
+	public const DEFAULT_FX_INTERVAL_TICKS = 5;
+
+	/** @var Player */
+	private $player;
+	/** @var Vector3 */
+	private $blockPos;
+	/** @var Block */
+	private $block;
+	/** @var int */
+	private $targetedFace;
+
+	/** @var int */
+	private $fxTicker = 0;
+	/** @var int */
+	private $fxTickInterval;
+	/** @var int */
+	private $maxPlayerDistance;
+
+	/** @var float|null */
+	private $breakSpeed;
+
+	/** @var float */
+	private $breakProgress = 0;
+
+	public function __construct(Player $player, Vector3 $blockPos, Block $block, int $targetedFace, int $maxPlayerDistance, int $fxTickInterval = self::DEFAULT_FX_INTERVAL_TICKS){
+		$this->player = $player;
+		$this->blockPos = $blockPos;
+		$this->block = $block;
+		$this->targetedFace = $targetedFace;
+		$this->fxTickInterval = $fxTickInterval;
+		$this->maxPlayerDistance = $maxPlayerDistance;
+
+		$this->breakSpeed = $this->calculateBreakProgressPerTick();
+		if($this->breakSpeed !== null){
+			$this->player->getWorld()->broadcastPacketToViewers(
+				$this->blockPos,
+				LevelEventPacket::create(LevelEventPacket::EVENT_BLOCK_START_BREAK, (int) (65535 * $this->breakSpeed), $this->blockPos)
+			);
+		}
+	}
+
+	/**
+	 * Returns the calculated break speed as percentage progress per game tick.
+	 */
+	private function calculateBreakProgressPerTick() : ?float{
+		//TODO: improve this to take stuff like swimming, ladders, enchanted tools into account, fix wrong tool break time calculations for bad tools (pmmp/PocketMine-MP#211)
+		$breakTime = $this->block->getBreakInfo()->getBreakTime($this->player->getInventory()->getItemInHand()) * 20;
+		if($breakTime > 0){
+			return 1 / $breakTime;
+		}
+		return null;
+	}
+
+	public function update() : bool{
+		if(
+			$this->player->getPosition()->distanceSquared($this->blockPos->add(0.5, 0.5, 0.5)) > $this->maxPlayerDistance){
+			return false;
+		}
+		if($this->breakSpeed !== null){
+			$newBreakSpeed = $this->calculateBreakProgressPerTick();
+			if(abs($newBreakSpeed - $this->breakSpeed) > 0.0001){
+				$this->breakSpeed = $newBreakSpeed;
+				//TODO: sync with client
+			}
+
+			$this->breakProgress += $this->breakSpeed;
+
+			if(($this->fxTicker++ % $this->fxTickInterval) === 0){
+				$this->player->getWorld()->addParticle($this->blockPos, new BlockPunchParticle($this->block, $this->targetedFace));
+				$this->player->getWorld()->addSound($this->blockPos, new BlockPunchSound($this->block));
+				$this->player->broadcastAnimation(new ArmSwingAnimation($this->player), $this->player->getViewers());
+			}
+		}
+		return $this->breakSpeed !== null and $this->breakProgress < 1;
+	}
+
+	public function getBlockPos() : Vector3{
+		return $this->blockPos;
+	}
+
+	public function getTargetedFace() : int{
+		return $this->targetedFace;
+	}
+
+	public function setTargetedFace(int $face) : void{
+		Facing::validate($face);
+		$this->targetedFace = $face;
+	}
+
+	public function getBreakSpeed() : ?float{
+		return $this->breakSpeed;
+	}
+
+	public function getBreakProgress() : float{
+		return $this->breakProgress;
+	}
+
+	public function __destruct(){
+		if($this->breakSpeed !== null and $this->player->getWorld()->isInLoadedTerrain($this->blockPos)){
+			$this->player->getWorld()->broadcastPacketToViewers(
+				$this->blockPos,
+				LevelEventPacket::create(LevelEventPacket::EVENT_BLOCK_STOP_BREAK, 0, $this->blockPos)
+			);
+		}
+	}
+}