Implemented rail connectivity (#2414)

src/pocketmine/block/ActivatorRail.php

@@ -23,7 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-class ActivatorRail extends Rail{
+class ActivatorRail extends RedstoneRail{
 
 	protected $id = self::ACTIVATOR_RAIL;
 

src/pocketmine/block/BaseRail.php

@@ -0,0 +1,266 @@
+<?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\block;
+
+use pocketmine\item\Item;
+use pocketmine\math\Vector3;
+use pocketmine\Player;
+
+abstract class BaseRail extends Flowable{
+
+	public const STRAIGHT_NORTH_SOUTH = 0;
+	public const STRAIGHT_EAST_WEST = 1;
+	public const ASCENDING_EAST = 2;
+	public const ASCENDING_WEST = 3;
+	public const ASCENDING_NORTH = 4;
+	public const ASCENDING_SOUTH = 5;
+
+	private const ASCENDING_SIDES = [
+		self::ASCENDING_NORTH => Vector3::SIDE_NORTH,
+		self::ASCENDING_EAST => Vector3::SIDE_EAST,
+		self::ASCENDING_SOUTH => Vector3::SIDE_SOUTH,
+		self::ASCENDING_WEST => Vector3::SIDE_WEST
+	];
+
+	protected const FLAG_ASCEND = 1 << 24; //used to indicate direction-up
+
+	protected const CONNECTIONS = [
+		//straights
+		self::STRAIGHT_NORTH_SOUTH => [
+			Vector3::SIDE_NORTH,
+			Vector3::SIDE_SOUTH
+		],
+		self::STRAIGHT_EAST_WEST => [
+			Vector3::SIDE_EAST,
+			Vector3::SIDE_WEST
+		],
+
+		//ascending
+		self::ASCENDING_EAST => [
+			Vector3::SIDE_WEST,
+			Vector3::SIDE_EAST | self::FLAG_ASCEND
+		],
+		self::ASCENDING_WEST => [
+			Vector3::SIDE_EAST,
+			Vector3::SIDE_WEST | self::FLAG_ASCEND
+		],
+		self::ASCENDING_NORTH => [
+			Vector3::SIDE_SOUTH,
+			Vector3::SIDE_NORTH | self::FLAG_ASCEND
+		],
+		self::ASCENDING_SOUTH => [
+			Vector3::SIDE_NORTH,
+			Vector3::SIDE_SOUTH | self::FLAG_ASCEND
+		]
+	];
+
+	public function __construct(int $meta = 0){
+		$this->meta = $meta;
+	}
+
+	public function getHardness() : float{
+		return 0.7;
+	}
+
+	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
+		if(!$blockReplace->getSide(Vector3::SIDE_DOWN)->isTransparent() and $this->getLevel()->setBlock($blockReplace, $this, true, true)){
+			$this->tryReconnect();
+			return true;
+		}
+
+		return false;
+	}
+
+	protected static function searchState(array $connections, array $lookup) : int{
+		$meta = array_search($connections, $lookup, true);
+		if($meta === false){
+			$meta = array_search(array_reverse($connections), $lookup, true);
+		}
+		if($meta === false){
+			throw new \InvalidArgumentException("No meta value matches connections " . implode(", ", array_map('dechex', $connections)));
+		}
+
+		return $meta;
+	}
+
+	/**
+	 * Returns a meta value for the rail with the given connections.
+	 *
+	 * @param array $connections
+	 *
+	 * @return int
+	 *
+	 * @throws \InvalidArgumentException if no state matches the given connections
+	 */
+	protected function getMetaForState(array $connections) : int{
+		return self::searchState($connections, self::CONNECTIONS);
+	}
+
+	/**
+	 * Returns the connection directions of this rail (depending on the current block state)
+	 *
+	 * @return int[]
+	 */
+	abstract protected function getConnectionsForState() : array;
+
+	/**
+	 * Returns all the directions this rail is already connected in.
+	 *
+	 * @return int[]
+	 */
+	private function getConnectedDirections() : array{
+		/** @var int[] $connections */
+		$connections = [];
+
+		/** @var int $connection */
+		foreach($this->getConnectionsForState() as $connection){
+			$other = $this->getSide($connection & ~self::FLAG_ASCEND);
+			$otherConnection = Vector3::getOppositeSide($connection & ~self::FLAG_ASCEND);
+
+			if(($connection & self::FLAG_ASCEND) !== 0){
+				$other = $other->getSide(Vector3::SIDE_UP);
+
+			}elseif(!($other instanceof BaseRail)){ //check for rail sloping up to meet this one
+				$other = $other->getSide(Vector3::SIDE_DOWN);
+				$otherConnection |= self::FLAG_ASCEND;
+			}
+
+			if(
+				$other instanceof BaseRail and
+				in_array($otherConnection, $other->getConnectionsForState(), true)
+			){
+				$connections[] = $connection;
+			}
+		}
+
+		return $connections;
+	}
+
+	private function getPossibleConnectionDirections(array $constraints) : array{
+		switch(count($constraints)){
+			case 0:
+				//No constraints, can connect in any direction
+				$possible = [
+					Vector3::SIDE_NORTH => true,
+					Vector3::SIDE_SOUTH => true,
+					Vector3::SIDE_WEST => true,
+					Vector3::SIDE_EAST => true
+				];
+				foreach($possible as $p => $_){
+					$possible[$p | self::FLAG_ASCEND] = true;
+				}
+
+				return $possible;
+			case 1:
+				return $this->getPossibleConnectionDirectionsOneConstraint(array_shift($constraints));
+			case 2:
+				return [];
+			default:
+				throw new \InvalidArgumentException("Expected at most 2 constraints, got " . count($constraints));
+		}
+	}
+
+	protected function getPossibleConnectionDirectionsOneConstraint(int $constraint) : array{
+		$opposite = Vector3::getOppositeSide($constraint & ~self::FLAG_ASCEND);
+
+		$possible = [$opposite => true];
+
+		if(($constraint & self::FLAG_ASCEND) === 0){
+			//We can slope the other way if this connection isn't already a slope
+			$possible[$opposite | self::FLAG_ASCEND] = true;
+		}
+
+		return $possible;
+	}
+
+	private function tryReconnect() : void{
+		$thisConnections = $this->getConnectedDirections();
+		$changed = false;
+
+		do{
+			$possible = $this->getPossibleConnectionDirections($thisConnections);
+			$continue = false;
+
+			foreach($possible as $thisSide => $_){
+				$otherSide = Vector3::getOppositeSide($thisSide & ~self::FLAG_ASCEND);
+
+				$other = $this->getSide($thisSide & ~self::FLAG_ASCEND);
+
+				if(($thisSide & self::FLAG_ASCEND) !== 0){
+					$other = $other->getSide(Vector3::SIDE_UP);
+
+				}elseif(!($other instanceof BaseRail)){ //check if other rails can slope up to meet this one
+					$other = $other->getSide(Vector3::SIDE_DOWN);
+					$otherSide |= self::FLAG_ASCEND;
+				}
+
+				if(!($other instanceof BaseRail) or count($otherConnections = $other->getConnectedDirections()) >= 2){
+					//we can only connect to a rail that has less than 2 connections
+					continue;
+				}
+
+				$otherPossible = $other->getPossibleConnectionDirections($otherConnections);
+
+				if(isset($otherPossible[$otherSide])){
+					$otherConnections[] = $otherSide;
+					$other->updateState($otherConnections);
+
+					$changed = true;
+					$thisConnections[] = $thisSide;
+					$continue = count($thisConnections) < 2;
+
+					break; //force recomputing possible directions, since this connection could invalidate others
+				}
+			}
+		}while($continue);
+
+		if($changed){
+			$this->updateState($thisConnections);
+		}
+	}
+
+	private function updateState(array $connections) : void{
+		if(count($connections) === 1){
+			$connections[] = Vector3::getOppositeSide($connections[0] & ~self::FLAG_ASCEND);
+		}elseif(count($connections) !== 2){
+			throw new \InvalidArgumentException("Expected exactly 2 connections, got " . count($connections));
+		}
+
+		$this->meta = $this->getMetaForState($connections);
+		$this->level->setBlock($this, $this, false, false); //avoid recursion
+	}
+
+	public function onNearbyBlockChange() : void{
+		if($this->getSide(Vector3::SIDE_DOWN)->isTransparent() or (
+			isset(self::ASCENDING_SIDES[$this->meta & 0x07]) and
+			$this->getSide(self::ASCENDING_SIDES[$this->meta & 0x07])->isTransparent()
+		)){
+			$this->getLevel()->useBreakOn($this);
+		}
+	}
+
+	public function getVariantBitmask() : int{
+		return 0;
+	}
+}

src/pocketmine/block/DetectorRail.php

@@ -23,7 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-class DetectorRail extends Rail{
+class DetectorRail extends RedstoneRail{
 
 	protected $id = self::DETECTOR_RAIL;
 

src/pocketmine/block/PoweredRail.php

@@ -23,7 +23,7 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-class PoweredRail extends Rail{
+class PoweredRail extends RedstoneRail{
 	protected $id = self::POWERED_RAIL;
 
 	public function getName() : string{

src/pocketmine/block/Rail.php

@@ -23,54 +23,71 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-use pocketmine\item\Item;
 use pocketmine\math\Vector3;
-use pocketmine\Player;
 
-class Rail extends Flowable{
+class Rail extends BaseRail{
 
-	public const STRAIGHT_NORTH_SOUTH = 0;
-	public const STRAIGHT_EAST_WEST = 1;
-	public const ASCENDING_EAST = 2;
-	public const ASCENDING_WEST = 3;
-	public const ASCENDING_NORTH = 4;
-	public const ASCENDING_SOUTH = 5;
+	/* extended meta values for regular rails, to allow curving */
 	public const CURVE_SOUTHEAST = 6;
 	public const CURVE_SOUTHWEST = 7;
 	public const CURVE_NORTHWEST = 8;
 	public const CURVE_NORTHEAST = 9;
 
-	protected $id = self::RAIL;
+	private const CURVE_CONNECTIONS = [
+		self::CURVE_SOUTHEAST => [
+			Vector3::SIDE_SOUTH,
+			Vector3::SIDE_EAST
+		],
+		self::CURVE_SOUTHWEST => [
+			Vector3::SIDE_SOUTH,
+			Vector3::SIDE_WEST
+		],
+		self::CURVE_NORTHWEST => [
+			Vector3::SIDE_NORTH,
+			Vector3::SIDE_WEST
+		],
+		self::CURVE_NORTHEAST => [
+			Vector3::SIDE_NORTH,
+			Vector3::SIDE_EAST
+		]
+	];
 
-	public function __construct(int $meta = 0){
-		$this->meta = $meta;
-	}
+	protected $id = self::RAIL;
 
 	public function getName() : string{
 		return "Rail";
 	}
 
-	public function getHardness() : float{
-		return 0.7;
-	}
-
-	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
-		if(!$blockReplace->getSide(Vector3::SIDE_DOWN)->isTransparent()){
-			return $this->getLevel()->setBlock($blockReplace, $this, true, true);
-		}
-
-		return false;
-	}
-
-	public function onNearbyBlockChange() : void{
-		if($this->getSide(Vector3::SIDE_DOWN)->isTransparent()){
-			$this->getLevel()->useBreakOn($this);
-		}else{
-			//TODO: Update rail connectivity
+	protected function getMetaForState(array $connections) : int{
+		try{
+			return self::searchState($connections, self::CURVE_CONNECTIONS);
+		}catch(\InvalidArgumentException $e){
+			return parent::getMetaForState($connections);
 		}
 	}
 
-	public function getVariantBitmask() : int{
-		return 0;
+	protected function getConnectionsForState() : array{
+		return self::CURVE_CONNECTIONS[$this->meta] ?? self::CONNECTIONS[$this->meta];
+	}
+
+	protected function getPossibleConnectionDirectionsOneConstraint(int $constraint) : array{
+		static $horizontal = [
+			Vector3::SIDE_NORTH,
+			Vector3::SIDE_SOUTH,
+			Vector3::SIDE_WEST,
+			Vector3::SIDE_EAST
+		];
+
+		$possible = parent::getPossibleConnectionDirectionsOneConstraint($constraint);
+
+		if(($constraint & self::FLAG_ASCEND) === 0){
+			foreach($horizontal as $d){
+				if($constraint !== $d){
+					$possible[$d] = true;
+				}
+			}
+		}
+
+		return $possible;
 	}
 }

src/pocketmine/block/RedstoneRail.php

@@ -0,0 +1,32 @@
+<?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\block;
+
+class RedstoneRail extends BaseRail{
+	protected const FLAG_POWERED = 0x08;
+
+	protected function getConnectionsForState() : array{
+		return self::CONNECTIONS[$this->meta & ~self::FLAG_POWERED];
+	}
+}