Some refactoring to allow for light updates to be executed asynchronously

src/pocketmine/level/light/BlockLightUpdate.php

@@ -0,0 +1,35 @@
+<?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\level\light;
+
+class BlockLightUpdate extends LightUpdate{
+
+	public function getLight(int $x, int $y, int $z) : int{
+		return $this->level->getBlockLightAt($x, $y, $z);
+	}
+
+	public function setLight(int $x, int $y, int $z, int $level){
+		$this->level->setBlockLightAt($x, $y, $z, $level);
+	}
+}

src/pocketmine/level/light/LightUpdate.php

@@ -0,0 +1,164 @@
+<?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\level\light;
+
+use pocketmine\block\Block;
+use pocketmine\level\ChunkManager;
+use pocketmine\level\Level;
+
+//TODO: make light updates asynchronous
+abstract class LightUpdate{
+
+	/** @var ChunkManager */
+	protected $level;
+
+	/** @var \SplQueue */
+	protected $spreadQueue;
+	/** @var bool[] */
+	protected $spreadVisited = [];
+
+	/** @var \SplQueue */
+	protected $removalQueue;
+	/** @var bool[] */
+	protected $removalVisited = [];
+
+	public function __construct(ChunkManager $level){
+		$this->level = $level;
+		$this->removalQueue = new \SplQueue();
+		$this->spreadQueue = new \SplQueue();
+	}
+
+	public function addSpreadNode(int $x, int $y, int $z){
+		$this->spreadQueue->enqueue([$x, $y, $z]);
+	}
+
+	public function addRemoveNode(int $x, int $y, int $z, int $oldLight){
+		$this->spreadQueue->enqueue([$x, $y, $z, $oldLight]);
+	}
+
+	abstract protected function getLight(int $x, int $y, int $z) : int;
+
+	abstract protected function setLight(int $x, int $y, int $z, int $level);
+
+	public function setAndUpdateLight(int $x, int $y, int $z, int $newLevel){
+		if(isset($this->spreadVisited[$index = Level::blockHash($x, $y, $z)]) or isset($this->removalVisited[$index])){
+			throw new \InvalidArgumentException("Already have a visit ready for this block");
+		}
+		$oldLevel = $this->getLight($x, $y, $z);
+
+		if($oldLevel !== $newLevel){
+			$this->setLight($x, $y, $z, $newLevel);
+			if($oldLevel < $newLevel){ //light increased
+				$this->spreadVisited[$index] = true;
+				$this->spreadQueue->enqueue([$x, $y, $z]);
+			}else{ //light removed
+				$this->removalVisited[$index] = true;
+				$this->removalQueue->enqueue([$x, $y, $z, $oldLevel]);
+			}
+		}
+	}
+
+	public function execute(){
+		while(!$this->removalQueue->isEmpty()){
+			list($x, $y, $z, $oldAdjacentLight) = $this->removalQueue->dequeue();
+
+			$points = [
+				[$x + 1, $y, $z],
+				[$x - 1, $y, $z],
+				[$x, $y + 1, $z],
+				[$x, $y - 1, $z],
+				[$x, $y, $z + 1],
+				[$x, $y, $z - 1]
+			];
+
+			foreach($points as list($cx, $cy, $cz)){
+				if($cy < 0){
+					continue;
+				}
+				$this->computeRemoveLight($cx, $cy, $cz, $oldAdjacentLight);
+			}
+		}
+
+		while(!$this->spreadQueue->isEmpty()){
+			list($x, $y, $z) = $this->spreadQueue->dequeue();
+
+			$newAdjacentLight = $this->getLight($x, $y, $z);
+			if($newAdjacentLight <= 0){
+				continue;
+			}
+
+			$points = [
+				[$x + 1, $y, $z],
+				[$x - 1, $y, $z],
+				[$x, $y + 1, $z],
+				[$x, $y - 1, $z],
+				[$x, $y, $z + 1],
+				[$x, $y, $z - 1]
+			];
+
+			foreach($points as list($cx, $cy, $cz)){
+				if($cy < 0){
+					continue;
+				}
+				$this->computeSpreadLight($cx, $cy, $cz, $newAdjacentLight);
+			}
+		}
+	}
+
+	protected function computeRemoveLight(int $x, int $y, int $z, int $oldAdjacentLevel){
+		$current = $this->getLight($x, $y, $z);
+
+		if($current !== 0 and $current < $oldAdjacentLevel){
+			$this->setLight($x, $y, $z, 0);
+
+			if(!isset($visited[$index = Level::blockHash($x, $y, $z)])){
+				$this->removalVisited[$index] = true;
+				if($current > 1){
+					$this->removalQueue->enqueue([$x, $y, $z, $current]);
+				}
+			}
+		}elseif($current >= $oldAdjacentLevel){
+			if(!isset($this->spreadVisited[$index = Level::blockHash($x, $y, $z)])){
+				$this->spreadVisited[$index] = true;
+				$this->spreadQueue->enqueue([$x, $y, $z]);
+			}
+		}
+	}
+
+	protected function computeSpreadLight(int $x, int $y, int $z, int $newAdjacentLevel){
+		$current = $this->getLight($x, $y, $z);
+		$potentialLight = $newAdjacentLevel - Block::$lightFilter[$this->level->getBlockIdAt($x, $y, $z)];
+
+		if($current < $potentialLight){
+			$this->setLight($x, $y, $z, $potentialLight);
+
+			if(!isset($this->spreadVisited[$index = Level::blockHash($x, $y, $z)])){
+				$this->spreadVisited[$index] = true;
+				if($potentialLight > 1){
+					$this->spreadQueue->enqueue([$x, $y, $z]);
+				}
+			}
+		}
+	}
+}

src/pocketmine/level/light/SkyLightUpdate.php

@@ -0,0 +1,35 @@
+<?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\level\light;
+
+class SkyLightUpdate extends LightUpdate{
+
+	public function getLight(int $x, int $y, int $z) : int{
+		return $this->level->getBlockSkyLightAt($x, $y, $z);
+	}
+
+	public function setLight(int $x, int $y, int $z, int $level){
+		$this->level->setBlockSkyLightAt($x, $y, $z, $level);
+	}
+}