From 6a86e92999abe09d0496afa46173ac127623d4d2 Mon Sep 17 00:00:00 2001
From: TheMode <themode@outlook.fr>
Date: Wed, 28 Jul 2021 16:36:21 +0200
Subject: [PATCH] Unload all chunks when changing instance

---
 src/main/java/net/minestom/server/entity/Player.java | 12 +++++-------
 .../packet/server/play/UnloadChunkPacket.java        | 12 ++++++++----
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/main/java/net/minestom/server/entity/Player.java b/src/main/java/net/minestom/server/entity/Player.java
index cb4216aae..0abb794e8 100644
--- a/src/main/java/net/minestom/server/entity/Player.java
+++ b/src/main/java/net/minestom/server/entity/Player.java
@@ -513,7 +513,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
      *
      * @param instance      the new player instance
      * @param spawnPosition the new position of the player
-     * @return
+     * @return a future called once the player instance changed
      */
     @Override
     public CompletableFuture<Void> setInstance(@NotNull Instance instance, @NotNull Pos spawnPosition) {
@@ -579,6 +579,9 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         super.setInstance(instance, spawnPosition);
 
         if (updateChunks) {
+            // Warning: loop to remove once `refreshVisibleChunks` manage it
+            this.viewableChunks.forEach(chunk ->
+                    playerConnection.sendPacket(new UnloadChunkPacket(chunk.getChunkX(), chunk.getChunkZ())));
             refreshVisibleChunks();
         }
 
@@ -1199,12 +1202,7 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         ArrayUtils.forDifferencesBetweenArray(lastVisibleChunks, updatedVisibleChunks, chunkIndex -> {
             final int chunkX = ChunkUtils.getChunkCoordX(chunkIndex);
             final int chunkZ = ChunkUtils.getChunkCoordZ(chunkIndex);
-
-            final UnloadChunkPacket unloadChunkPacket = new UnloadChunkPacket();
-            unloadChunkPacket.chunkX = chunkX;
-            unloadChunkPacket.chunkZ = chunkZ;
-            //playerConnection.sendPacket(unloadChunkPacket);
-
+            //playerConnection.sendPacket(new UnloadChunkPacket(chunkX, chunkZ));
             final Chunk chunk = instance.getChunk(chunkX, chunkZ);
             if (chunk != null) {
                 chunk.removeViewer(this);
diff --git a/src/main/java/net/minestom/server/network/packet/server/play/UnloadChunkPacket.java b/src/main/java/net/minestom/server/network/packet/server/play/UnloadChunkPacket.java
index 638e70781..463bd7e9f 100644
--- a/src/main/java/net/minestom/server/network/packet/server/play/UnloadChunkPacket.java
+++ b/src/main/java/net/minestom/server/network/packet/server/play/UnloadChunkPacket.java
@@ -10,10 +10,14 @@ public class UnloadChunkPacket implements ServerPacket {
 
     public int chunkX, chunkZ;
 
-    /**
-     * Default constructor, required for reflection operations.
-     */
-    public UnloadChunkPacket() {}
+    public UnloadChunkPacket(int chunkX, int chunkZ) {
+        this.chunkX = chunkX;
+        this.chunkZ = chunkZ;
+    }
+
+    public UnloadChunkPacket() {
+        this(0, 0);
+    }
 
     @Override
     public void write(@NotNull BinaryWriter writer) {