From f2a5d9adec2129bfd795271853155317e0b41a0c Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <blake.galbreath@gmail.com>
Date: Sat, 6 Jul 2019 20:31:10 -0500
Subject: [PATCH] Dont send useless entity packets

---
 docs/source/configuration.rst                 |  8 +++
 ...042-Dont-send-useless-entity-packets.patch | 64 +++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 patches/server/0042-Dont-send-useless-entity-packets.patch

diff --git a/docs/source/configuration.rst b/docs/source/configuration.rst
index 34558a6c0..2a314b681 100644
--- a/docs/source/configuration.rst
+++ b/docs/source/configuration.rst
@@ -50,6 +50,14 @@ disable-drops-on-cramming-death
 * **default**: true
 * **description**: Stops entities from dropping loot on death, if killed by cramming gamerule
 
+dont-send-useless-entity-packets
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+* **default**: false
+* **description**: Skips sending relative move packets for entities that didn't really move
+
+.. warning::
+    The `dont-send-useless-entity-packets` option is highly experimental! Only enable this if you are feeling brave.
+
 large-ender-chests
 ~~~~~~~~~~~~~~
 * **default**: true
diff --git a/patches/server/0042-Dont-send-useless-entity-packets.patch b/patches/server/0042-Dont-send-useless-entity-packets.patch
new file mode 100644
index 000000000..bf6029ed6
--- /dev/null
+++ b/patches/server/0042-Dont-send-useless-entity-packets.patch
@@ -0,0 +1,64 @@
+From fa1344452a898367f0a83109c7e17625139c7ce0 Mon Sep 17 00:00:00 2001
+From: William Blake Galbreath <blake.galbreath@gmail.com>
+Date: Sat, 6 Jul 2019 17:00:04 -0500
+Subject: [PATCH] Dont send useless entity packets
+
+---
+ .../minecraft/server/EntityTrackerEntry.java    | 17 +++++++++++++++++
+ src/main/java/net/pl3x/purpur/PurpurConfig.java |  5 +++++
+ 2 files changed, 22 insertions(+)
+
+diff --git a/src/main/java/net/minecraft/server/EntityTrackerEntry.java b/src/main/java/net/minecraft/server/EntityTrackerEntry.java
+index 460c687d3..448602057 100644
+--- a/src/main/java/net/minecraft/server/EntityTrackerEntry.java
++++ b/src/main/java/net/minecraft/server/EntityTrackerEntry.java
+@@ -162,6 +162,7 @@ public class EntityTrackerEntry {
+                         this.o = 0;
+                         packet1 = new PacketPlayOutEntityTeleport(this.tracker);
+                     }
++                    if (net.pl3x.purpur.PurpurConfig.dontSendUselessEntityPackets && isUselessPacket(packet1)) packet1 = null; // Purpur
+                 }
+ 
+                 if ((this.e || this.tracker.impulse || this.tracker instanceof EntityLiving && ((EntityLiving) this.tracker).isGliding()) && this.n > 0) {
+@@ -248,6 +249,22 @@ public class EntityTrackerEntry {
+ 
+     }
+ 
++    // Purpur start
++    private boolean isUselessPacket(Packet<?> packet) {
++        if (packet instanceof PacketPlayOutEntity) {
++            PacketPlayOutEntity p = (PacketPlayOutEntity) packet;
++            if (packet instanceof PacketPlayOutEntity.PacketPlayOutRelEntityMove) {
++                return p.b == 0 && p.c == 0 && p.d == 0;
++            } else if (packet instanceof PacketPlayOutEntity.PacketPlayOutRelEntityMoveLook) {
++                return p.b == 0 && p.c == 0 && p.d == 0 && p.e == 0 && p.f == 0;
++            } else if (packet instanceof PacketPlayOutEntity.PacketPlayOutEntityLook) {
++                return p.e == 0 && p.f == 0;
++            }
++        }
++        return false;
++    }
++    // Purpur end
++
+     public void a(EntityPlayer entityplayer) {
+         this.tracker.c(entityplayer);
+         entityplayer.c(this.tracker);
+diff --git a/src/main/java/net/pl3x/purpur/PurpurConfig.java b/src/main/java/net/pl3x/purpur/PurpurConfig.java
+index b4f8cca53..c0ae6accd 100644
+--- a/src/main/java/net/pl3x/purpur/PurpurConfig.java
++++ b/src/main/java/net/pl3x/purpur/PurpurConfig.java
+@@ -141,6 +141,11 @@ public class PurpurConfig {
+         disableDropsOnCrammingDeath = getBoolean("settings.disable-drops-on-cramming-death", disableDropsOnCrammingDeath);
+     }
+ 
++    public static boolean dontSendUselessEntityPackets = false;
++    private static void dontSendUselessEntityPackets() {
++        dontSendUselessEntityPackets = getBoolean("settings.dont-send-useless-entity-packets", dontSendUselessEntityPackets);
++    }
++
+     public static boolean requireShiftToMount = true;
+     private static void requireShiftToMount() {
+         requireShiftToMount = getBoolean("settings.mobs.require-shift-to-mount", requireShiftToMount);
+-- 
+2.20.1
+