Automatic population on side loading

src/world/generator/populator/TreePopulator.php

@@ -0,0 +1,67 @@
+<?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/
+ * 
+ *
+*/
+
+class TreePopulator extends Populator{
+	private $level;
+	private $randomAmount;
+	private $baseAmount;
+	
+	public function setRandomAmount($amount){
+		$this->randomAmount = $amount;
+	}
+	
+	public function setBaseAmount($amount){
+		$this->baseAmount = $amount;
+	}
+	
+	public function populate(Level $level, $chunkX, $chunkZ, Random $random){
+		$this->level = $level;
+		$amount = $random->nextRange(0, $this->randomAmount + 1) + $this->baseAmount;
+		for($i = 0; $i < $amount; ++$i){
+			$x = $random->nextRange($chunkX << 4, ($chunkX << 4) + 15);
+			$z = $random->nextRange($chunkZ << 4, ($chunkZ << 4) + 15);
+			$y = $this->getHighestWorkableBlock($x, $z);
+			if($y === -1){
+				continue;
+			}			
+			if($random->nextFloat() > 0.75){
+				$meta = 1;
+			}else{
+				$meta = 0;
+			}
+			TreeObject::growTree($this->level, new Vector3($x, $y, $z), $random, $meta);
+		}
+	}
+	
+	private function getHighestWorkableBlock($x, $z){
+		for($y = 128; $y > 0; --$y){
+			$b = $this->level->getBlockRaw(new Vector3($x, $y, $z));
+			if($b->getID() !== DIRT and $b->getID() !== GRASS){
+				if(--$y <= 0){
+					return -1;
+				}				
+			}else{
+				break;
+			}
+		}
+		return ++$y;
+	}
+}