Paper/patches/server/0859-Only-tick-item-frames-if-players-can-see-it.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Redned <redned235@gmail.com>
Date: Mon, 19 Jun 2023 15:45:53 -0500
Subject: [PATCH] Only tick item frames if players can see it

In the event that an item frame cannot be seen by any players, ticking the item frame every tick is unnecessary. This can be a very hot section of the entity tracker when lots of item frames are present on a server, so this reduces the logic which speeds it up.

diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
index f355dd986bf861da3edb90d7e05f901e19686fef..b195de05371e9762654b69365f0e722443425d33 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -113,7 +113,7 @@ public class ServerEntity {
 
         Entity entity = this.entity;
 
-        if (entity instanceof ItemFrame entityitemframe) {
+        if (!this.trackedPlayers.isEmpty() && entity instanceof ItemFrame) { // Paper - Perf: Only tick item frames if players can see it
             if (true || this.tickCount % 10 == 0) { // CraftBukkit - Moved below, should always enter this block
                 ItemStack itemstack = entityitemframe.getItem();