From 7aa4c18afa7828213e05c49b17007d087bea60f8 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Mon, 4 Mar 2019 16:50:10 -0500
Subject: [PATCH] Fixed assert failure in SubChunk

---
 src/pocketmine/level/format/SubChunk.php | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/pocketmine/level/format/SubChunk.php b/src/pocketmine/level/format/SubChunk.php
index cd3ceb0c9..857277fe8 100644
--- a/src/pocketmine/level/format/SubChunk.php
+++ b/src/pocketmine/level/format/SubChunk.php
@@ -138,11 +138,9 @@ class SubChunk implements SubChunkInterface{
 	}
 
 	public function getHighestBlockAt(int $x, int $z) : int{
-		$low = ($x << 8) | ($z << 4);
-		$i = $low | 0x0f;
-		for(; $i >= $low; --$i){
-			if(($this->blockLayers[0]->get($x, $i, $z) >> 4) !== BlockIds::AIR){
-				return $i & 0x0f;
+		for($y = 15; $y >= 0; --$y){
+			if(($this->blockLayers[0]->get($x, $y, $z) >> 4) !== BlockIds::AIR){
+				return $y;
 			}
 		}