Fixed slabs again

Author: dktapps

src/pocketmine/block/Block.php

@@ -164,7 +164,7 @@ public function canBeReplaced() : bool{
 		return false;
 	}
 
-	public function canBePlacedAt(Block $blockReplace, Vector3 $clickVector) : bool{
+	public function canBePlacedAt(Block $blockReplace, Vector3 $clickVector, int $face, bool $isClickedBlock) : bool{
 		return $blockReplace->canBeReplaced();
 	}
 

src/pocketmine/block/Slab.php

@@ -36,16 +36,20 @@ public function __construct(int $meta = 0){
 
 	abstract public function getDoubleSlabId() : int;
 
-	public function canBePlacedAt(Block $blockReplace, Vector3 $clickVector) : bool{
-		return parent::canBePlacedAt($blockReplace, $clickVector) or
-			(
-				$blockReplace->getId() === $this->getId() and
-				$blockReplace->getVariant() === $this->getVariant() and
-				(
-					(($blockReplace->getDamage() & 0x08) !== 0 and ($clickVector->y <= 0.5 or $clickVector->y === 1.0)) or //top slab, fill bottom half
-					(($blockReplace->getDamage() & 0x08) === 0 and ($clickVector->y >= 0.5 or $clickVector->y === 0.0)) //bottom slab, fill top half
-				)
-			);
+	public function canBePlacedAt(Block $blockReplace, Vector3 $clickVector, int $face, bool $isClickedBlock) : bool{
+		if(parent::canBePlacedAt($blockReplace, $clickVector, $face, $isClickedBlock)){
+			return true;
+		}
+
+		if($blockReplace->getId() === $this->getId() and $blockReplace->getVariant() === $this->getVariant()){
+			if(($blockReplace->getDamage() & 0x08) !== 0){ //Trying to combine with top slab
+				return $clickVector->y <= 0.5 or (!$isClickedBlock and $face === Vector3::SIDE_UP);
+			}else{
+				return $clickVector->y >= 0.5 or (!$isClickedBlock and $face === Vector3::SIDE_DOWN);
+			}
+		}
+
+		return false;
 	}
 
 	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $facePos, Player $player = null) : bool{

src/pocketmine/level/Level.php

@@ -1793,10 +1793,10 @@ public function useItemOn(Vector3 $vector, Item &$item, int $face, Vector3 $face
 			return false;
 		}
 
-		if($hand->canBePlacedAt($blockClicked, $facePos)){
+		if($hand->canBePlacedAt($blockClicked, $facePos, $face, true)){
 			$blockReplace = $blockClicked;
 			$hand->position($blockReplace);
-		}elseif(!$hand->canBePlacedAt($blockReplace, $facePos)){
+		}elseif(!$hand->canBePlacedAt($blockReplace, $facePos, $face, false)){
 			return false;
 		}