PaperMC/patches/server/0821-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 bc0f1aa61e68d2a8638d89c10bc5c71922d057f9..3cdcc4f44608d24550f2a8c6f3f5ce675d7777c5 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -116,7 +116,7 @@ public class ServerEntity {
 
         Entity entity = this.entity;
 
-        if (entity instanceof ItemFrame entityitemframe) {
+        if (!this.trackedPlayers.isEmpty() && entity instanceof ItemFrame entityitemframe) { // 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();