Add helper methods for layer emptiness checks and update serializers

- Add isBlockLayerEmpty() and isLiquidLayerEmpty() methods to SubChunk to avoid code duplication
- Update ChunkSerializer to use emptiness checks instead of null checks for layers
- Update LevelDB to use the new helper methods for cleaner code
- Ensures consistent emptiness checking logic across all serializers

src/network/mcpe/serializer/ChunkSerializer.php

@@ -112,13 +112,13 @@ final class ChunkSerializer{
 	}
 
 	public static function serializeSubChunk(SubChunk $subChunk, BlockTranslator $blockTranslator, PacketSerializer $stream, bool $persistentBlockStates) : void{
-		// Create array from the new methods to minimize code changes
+		// Create array from non-empty layers
 		$layers = [];
-		if(($blockLayer = $subChunk->getBlockLayer()) !== null){
+		if(!$subChunk->isBlockLayerEmpty()){
-			$layers[] = $blockLayer;
+			$layers[] = $subChunk->getBlockLayer();
 		}
-		if(($liquidLayer = $subChunk->getLiquidLayer()) !== null){
+		if(!$subChunk->isLiquidLayerEmpty()){
-			$layers[] = $liquidLayer;
+			$layers[] = $subChunk->getLiquidLayer();
 		}
 		
 		$stream->putByte(8); //version

src/world/format/SubChunk.php

@@ -76,6 +76,20 @@ class SubChunk{
 			   $this->liquidLayer->getBitsPerBlock() === 0 && $this->liquidLayer->get(0, 0, 0) === $this->emptyBlockId;
 	}
 
+	/**
+	 * Returns whether the block layer is empty (contains only empty blocks).
+	 */
+	public function isBlockLayerEmpty() : bool{
+		return $this->blockLayer->getBitsPerBlock() === 0 && $this->blockLayer->get(0, 0, 0) === $this->emptyBlockId;
+	}
+
+	/**
+	 * Returns whether the liquid layer is empty (contains only empty blocks).
+	 */
+	public function isLiquidLayerEmpty() : bool{
+		return $this->liquidLayer->getBitsPerBlock() === 0 && $this->liquidLayer->get(0, 0, 0) === $this->emptyBlockId;
+	}
+
 	/**
 	 * Returns the block used as the default. This is assumed to refer to air.
 	 * If all the blocks in a subchunk layer are equal to this block, the layer is assumed to be empty.

src/world/format/io/leveldb/LevelDB.php

@@ -778,8 +778,8 @@ class LevelDB extends BaseWorldProvider implements WritableWorldProvider{
 					$blockLayer = $subChunk->getBlockLayer();
 					$liquidLayer = $subChunk->getLiquidLayer();
 					
-					$isBlockLayerEmpty = $blockLayer->getBitsPerBlock() === 0 && $blockLayer->get(0, 0, 0) === $subChunk->getEmptyBlockId();
+					$isBlockLayerEmpty = $subChunk->isBlockLayerEmpty();
-					$isLiquidLayerEmpty = $liquidLayer->getBitsPerBlock() === 0 && $liquidLayer->get(0, 0, 0) === $subChunk->getEmptyBlockId();
+					$isLiquidLayerEmpty = $subChunk->isLiquidLayerEmpty();
 					
 					$layerCount = 0;
 					if(!$isBlockLayerEmpty) $layerCount++;