From fd0be11a5ce06767e30b2d3f424712d24edc28f7 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 20 Feb 2013 11:58:47 -0500
Subject: [PATCH] Entity Tracking Ranges

This will let you configure how far to track entities in range from players, so that the entity does not render on the client if out of this range.
This has multiple benefits:

1) Less bandwidth. Not sending update packets for entities that are not even close to a player, or even close enough to clearly see.
2) Less lag by maps in item frames - Default range is 160 blocks... Many players can track that item frame and cause lag and not even see it.
3) Less lag in general - Less work for the server to do
4) Less client lag - Not trying to render distant item frames and paintings and entities will reduce entity count on the client, which is major for shop/town worlds which may use tons of item frames.

diff --git a/src/main/java/net/minecraft/server/EntityTracker.java b/src/main/java/net/minecraft/server/EntityTracker.java
index d7efe3e..59586c2 100644
--- a/src/main/java/net/minecraft/server/EntityTracker.java
+++ b/src/main/java/net/minecraft/server/EntityTracker.java
@@ -90,6 +90,7 @@ public class EntityTracker {
 
     public void addEntity(Entity entity, int i, int j, boolean flag) {
         if (Thread.currentThread() != MinecraftServer.getServer().primaryThread) throw new IllegalStateException("Asynchronous entity track!"); // Spigot
+        i = org.spigotmc.TrackingRange.getEntityTrackingRange(entity, i); // Spigot
         if (i > this.d) {
             i = this.d;
         }
diff --git a/src/main/java/org/spigotmc/SpigotWorldConfig.java b/src/main/java/org/spigotmc/SpigotWorldConfig.java
index 31f4c39..8ae36fe 100644
--- a/src/main/java/org/spigotmc/SpigotWorldConfig.java
+++ b/src/main/java/org/spigotmc/SpigotWorldConfig.java
@@ -153,4 +153,19 @@ public class SpigotWorldConfig
         miscActivationRange = getInt( "entity-activation-range.misc", miscActivationRange );
         log( "Entity Activation Range: An " + animalActivationRange + " / Mo " + monsterActivationRange + " / Mi " + miscActivationRange );
     }
+
+    public int playerTrackingRange = 48;
+    public int animalTrackingRange = 48;
+    public int monsterTrackingRange = 48;
+    public int miscTrackingRange = 32;
+    public int maxTrackingRange = 64;
+    private void trackingRange()
+    {
+        playerTrackingRange = getInt( "entity-tracking-range.players", playerTrackingRange );
+        animalTrackingRange = getInt( "entity-tracking-range.animals", animalTrackingRange );
+        monsterTrackingRange = getInt( "entity-tracking-range.monsters", monsterTrackingRange );
+        miscTrackingRange = getInt( "entity-tracking-range.misc", miscTrackingRange );
+        maxTrackingRange = getInt( "entity-tracking-range.other", maxTrackingRange );
+        log( "Entity Tracking Range: Pl " + playerTrackingRange + " / An " + animalTrackingRange + " / Mo " + monsterTrackingRange + " / Mi " + miscTrackingRange + " / Other " + maxTrackingRange );
+    }
 }
diff --git a/src/main/java/org/spigotmc/TrackingRange.java b/src/main/java/org/spigotmc/TrackingRange.java
new file mode 100644
index 0000000..bc6438d
--- /dev/null
+++ b/src/main/java/org/spigotmc/TrackingRange.java
@@ -0,0 +1,45 @@
+package org.spigotmc;
+
+import net.minecraft.server.Entity;
+import net.minecraft.server.EntityExperienceOrb;
+import net.minecraft.server.EntityGhast;
+import net.minecraft.server.EntityItem;
+import net.minecraft.server.EntityItemFrame;
+import net.minecraft.server.EntityPainting;
+import net.minecraft.server.EntityPlayer;
+
+public class TrackingRange
+{
+
+    /**
+     * Gets the range an entity should be 'tracked' by players and visible in
+     * the client.
+     *
+     * @param entity
+     * @param defaultRange Default range defined by Mojang
+     * @return
+     */
+    public static int getEntityTrackingRange(Entity entity, int defaultRange)
+    {
+        SpigotWorldConfig config = entity.world.spigotConfig;
+        int range = defaultRange;
+        if ( entity instanceof EntityPlayer )
+        {
+            range = config.playerTrackingRange;
+        } else if ( entity.defaultActivationState || entity instanceof EntityGhast )
+        {
+            range = defaultRange;
+        } else if ( entity.activationType == 1 )
+        {
+            range = config.monsterTrackingRange;
+        } else if ( entity.activationType == 2 )
+        {
+            range = config.animalTrackingRange;
+        } else if ( entity instanceof EntityItemFrame || entity instanceof EntityPainting || entity instanceof EntityItem || entity instanceof EntityExperienceOrb )
+        {
+            range = config.miscTrackingRange;
+        }
+
+        return Math.min( config.maxTrackingRange, range );
+    }
+}
-- 
1.8.1.2