From ab75838c89b750a34bf2485e0b9c11a94de7a3c4 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Sat, 10 Jun 2023 18:35:42 +0100
Subject: [PATCH] First shot at implementing acacia trees this is mostly
 working, but due to some issue with leaf decay, the edges of the larger
 canopy will decay within minutes.

I don't know why this is yet, but it's likely some incorrect implementation of Leaves causing the problem.

In addition, the secondary branch of acacia may generate next to the base block of the trunk, which I've never observed to happen in vanilla. This has a 2% chance of occurring, so I haven't been able to rule it out yet, but it probably shouldn't happen.
---
 src/world/generator/object/AcaciaTree.php  | 132 +++++++++++++++++++++
 src/world/generator/object/TreeFactory.php |   2 +
 2 files changed, 134 insertions(+)
 create mode 100644 src/world/generator/object/AcaciaTree.php

diff --git a/src/world/generator/object/AcaciaTree.php b/src/world/generator/object/AcaciaTree.php
new file mode 100644
index 000000000..75e58a9b3
--- /dev/null
+++ b/src/world/generator/object/AcaciaTree.php
@@ -0,0 +1,132 @@
+<?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\world\generator\object;
+
+use pocketmine\block\VanillaBlocks;
+use pocketmine\math\Facing;
+use pocketmine\math\Vector3;
+use pocketmine\utils\Random;
+use pocketmine\world\BlockTransaction;
+use function abs;
+use function array_rand;
+
+final class AcaciaTree extends Tree{
+	private const MIN_HEIGHT = 5;
+
+	private ?Vector3 $mainBranchTip = null;
+	private ?Vector3 $secondBranchTip = null;
+
+	public function __construct(){
+		parent::__construct(
+			VanillaBlocks::ACACIA_LOG(),
+			VanillaBlocks::ACACIA_LEAVES(),
+			0 //we don't use this anyway - everything is overridden
+		);
+	}
+
+	protected function generateTrunkHeight(Random $random) : int{
+		//50% chance of 2 extra blocks, 33% chance 1 or 3, 17% chance 0 or 4
+		return self::MIN_HEIGHT + $random->nextRange(0, 2) + $random->nextRange(0, 2);
+	}
+
+	protected function placeTrunk(int $x, int $y, int $z, Random $random, int $trunkHeight, BlockTransaction $transaction) : void{
+		// The base dirt block
+		$transaction->addBlockAt($x, $y - 1, $z, VanillaBlocks::DIRT());
+
+		$firstBranchHeight = $trunkHeight - 1 - $random->nextRange(0, 3);
+
+		for($yy = 0; $yy <= $firstBranchHeight; ++$yy){
+			$transaction->addBlockAt($x, $y + $yy, $z, $this->trunkBlock);
+		}
+
+		$mainBranchFacing = Facing::HORIZONTAL[array_rand(Facing::HORIZONTAL)];
+
+		//this branch may grow a second trunk if the diagonal length is less than the max length
+		$this->mainBranchTip = $this->placeBranch(
+			$transaction,
+			new Vector3($x, $y + $firstBranchHeight, $z),
+			$mainBranchFacing,
+			$random->nextRange(1, 3),
+			$trunkHeight - $firstBranchHeight
+		);
+
+		$secondBranchFacing = Facing::HORIZONTAL[array_rand(Facing::HORIZONTAL)];
+		if($secondBranchFacing !== $mainBranchFacing){
+			$secondBranchLength = $random->nextRange(1, 3);
+			$this->secondBranchTip = $this->placeBranch(
+				$transaction,
+				new Vector3($x, $y + ($firstBranchHeight - $random->nextRange(0, 1)), $z),
+				$secondBranchFacing,
+				$secondBranchLength,
+				$secondBranchLength //the secondary branch may not form a second trunk
+			);
+		}
+	}
+
+	protected function placeBranch(BlockTransaction $transaction, Vector3 $start, int $branchFacing, int $maxDiagonal, int $length) : Vector3{
+		$diagonalPlaced = 0;
+
+		$nextBlockPos = $start;
+		for($yy = 0; $yy < $length; $yy++){
+			$nextBlockPos = $nextBlockPos->up();
+			if($diagonalPlaced < $maxDiagonal){
+				$nextBlockPos = $nextBlockPos->getSide($branchFacing);
+				$diagonalPlaced++;
+			}
+			$transaction->addBlock($nextBlockPos, $this->trunkBlock);
+		}
+
+		return $nextBlockPos;
+	}
+
+	protected function placeCanopyLayer(BlockTransaction $transaction, Vector3 $center, int $radius, int $maxTaxicabDistance) : void{
+		$centerX = $center->getFloorX();
+		$centerY = $center->getFloorY();
+		$centerZ = $center->getFloorZ();
+
+		for($x = $centerX - $radius; $x <= $centerX + $radius; ++$x){
+			for($z = $centerZ - $radius; $z <= $centerZ + $radius; ++$z){
+				if(
+					abs($x - $centerX) + abs($z - $centerZ) <= $maxTaxicabDistance &&
+					$transaction->fetchBlockAt($x, $centerY, $z)->canBeReplaced()
+				){
+					$transaction->addBlockAt($x, $centerY, $z, $this->leafBlock);
+				}
+			}
+		}
+	}
+
+	protected function placeCanopy(int $x, int $y, int $z, Random $random, BlockTransaction $transaction) : void{
+		$mainBranchTip = $this->mainBranchTip;
+		if($mainBranchTip !== null){
+			$this->placeCanopyLayer($transaction, $mainBranchTip, radius: 3, maxTaxicabDistance: 5);
+			$this->placeCanopyLayer($transaction, $mainBranchTip->up(), radius: 2, maxTaxicabDistance: 2);
+		}
+		$secondBranchTip = $this->secondBranchTip;
+		if($secondBranchTip !== null){
+			$this->placeCanopyLayer($transaction, $secondBranchTip, radius: 2, maxTaxicabDistance: 3);
+			$this->placeCanopyLayer($transaction, $secondBranchTip->up(), radius: 1, maxTaxicabDistance: 2);
+		}
+	}
+}
diff --git a/src/world/generator/object/TreeFactory.php b/src/world/generator/object/TreeFactory.php
index ecab73c79..1d95a77b1 100644
--- a/src/world/generator/object/TreeFactory.php
+++ b/src/world/generator/object/TreeFactory.php
@@ -49,6 +49,8 @@ final class TreeFactory{
 			}else{*/
 
 			//}
+		}elseif($type->equals(TreeType::ACACIA())){
+			return new AcaciaTree();
 		}
 		return null;
 	}