A nicer fix involving tracking dirty chunks.

Server/src/main/core/game/world/GameWorld.kt

@@ -18,7 +18,9 @@ import core.ServerStore
 import core.auth.AuthProvider
 import core.auth.Auth
 import core.game.system.config.ConfigParser
+import core.game.world.map.RegionChunk
 import core.game.world.repository.Repository
+import core.game.world.update.ChunkUpdateTracker
 import core.plugin.ClassScanner
 import core.storage.AccountStorageProvider
 import core.tools.Log
@@ -164,6 +166,7 @@ object GameWorld {
     fun prompt(run: Boolean, directory: String?){
         log(GameWorld::class.java, Log.FINE, "Prompting ${settings?.name} Game World...")
         Cache.init(ServerConstants.CACHE_PATH)
+        RegionChunk.dirtyListener = ChunkUpdateTracker
         //go overboard with checks to make sure dev mode authenticator never triggers on live
         Auth.configure()
         ConfigParser().prePlugin()

Server/src/main/core/game/world/map/RegionChunk.java

@@ -9,6 +9,7 @@ import core.game.node.scenery.Constructed;
 import core.game.node.scenery.Scenery;
 import core.game.node.scenery.SceneryBuilder;
 import core.game.world.map.build.ChunkFlags;
+import core.game.world.update.ChunkDirtyListener;
 import core.game.world.update.flag.chunk.ItemUpdateFlag;
 import core.net.packet.PacketRepository;
 import core.net.packet.context.BuildItemContext;
@@ -41,6 +42,11 @@ public class RegionChunk {
 	 */
 	public static final int SIZE = 8;
 
+	/**
+	 * Notified whenever a chunk is flagged, so the rendering pipeline can reset only the chunks that were actually touched.
+	 */
+	public static ChunkDirtyListener dirtyListener = chunk -> {};
+
 	/**
 	 * The base location of the copied region chunk.
 	 */
@@ -345,6 +351,7 @@ public class RegionChunk {
 	 */
 	public void flag(UpdateFlag<?> flag) {
 		updateFlags.add(flag);
+		dirtyListener.onFlagged(this);
 	}
 
 	/**

Server/src/main/core/game/world/map/RegionManager.kt

@@ -62,22 +62,6 @@ object RegionManager {
         }
     }
 
-    /**
-     * Pulses the active regions.
-     */
-    @JvmStatic
-    fun pulse() {
-        apply { r ->
-            for (x in 0 until 8) {
-                for (y in 0 until 8) {
-                    for (z in 0 until 4) {
-                        r.chunks[x][y][z]?.resetFlags()
-                    }
-                }
-            }
-        }
-    }
-
     /**
      * Gets the clipping flag.
      * @param z The plane.

Server/src/main/core/game/world/update/ChunkDirtyListener.kt

@@ -0,0 +1,7 @@
+package core.game.world.update
+
+import core.game.world.map.RegionChunk
+
+fun interface ChunkDirtyListener {
+    fun onFlagged(chunk: RegionChunk)
+}

Server/src/main/core/game/world/update/ChunkUpdateTracker.kt

@@ -0,0 +1,19 @@
+package core.game.world.update
+
+import core.game.world.map.RegionChunk
+import java.util.Collections
+import java.util.IdentityHashMap
+
+object ChunkUpdateTracker : ChunkDirtyListener {
+    private val dirty = Collections.newSetFromMap(IdentityHashMap<RegionChunk, Boolean>())
+
+    override fun onFlagged(chunk: RegionChunk) {
+        dirty.add(chunk)
+    }
+
+    /** Resets flags on exactly the chunks flagged this tick. Must run after all per-player flushes. */
+    fun resetAll() {
+        dirty.forEach { it.resetFlags() }
+        dirty.clear()
+    }
+}

Server/src/main/core/game/world/update/UpdateSequence.kt

@@ -59,7 +59,7 @@ class UpdateSequence
         playersList!!.forEach(Player::reset)
         npcList!!.forEach(NPC::reset)
         renderablePlayers.sync()
-        RegionManager.pulse()
+        ChunkUpdateTracker.resetAll()
         GroundItemManager.pulse()
     }