From 0000000000000000000000000000000000000000 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

TODO: Add more reducers

Original license: MIT
Original project: https://github.com/PurpurMC/Purpur

diff --git a/net/minecraft/server/level/ServerEntity.java b/net/minecraft/server/level/ServerEntity.java
index d6b261f8d3fbeee771208528b3e0bd5fcd94878b..1a9601aee097b6c10cf2ae1c52fddf45da85f60f 100644
--- a/net/minecraft/server/level/ServerEntity.java
+++ b/net/minecraft/server/level/ServerEntity.java
@@ -221,6 +221,8 @@ public class ServerEntity {
                 }
                 // Gale end - Airplane - better checking for useless move packets
 
+                if (org.dreeam.leaf.config.modules.opt.ReduceUselessPackets.reduceUselessEntityMovePackets && isUselessMoveEntityPacket(packet)) packet = null; // Purpur
+
                 if (this.entity.hasImpulse || this.trackDelta || this.entity instanceof LivingEntity && ((LivingEntity)this.entity).isFallFlying()) {
                     Vec3 deltaMovement = this.entity.getDeltaMovement();
                     if (deltaMovement != this.lastSentMovement) { // SparklyPaper start - skip distanceToSqr call in ServerEntity#sendChanges if the delta movement hasn't changed
@@ -304,6 +306,21 @@ public class ServerEntity {
         );
     }
 
+    // Purpur start
+    private boolean isUselessMoveEntityPacket(@Nullable Packet<?> packet) {
+        if (!(packet instanceof ClientboundMoveEntityPacket moveEntityPacket)) return false;
+        return switch (packet) {
+            case ClientboundMoveEntityPacket.Pos ignored ->
+                moveEntityPacket.getXa() == 0 && moveEntityPacket.getYa() == 0 && moveEntityPacket.getZa() == 0;
+            case ClientboundMoveEntityPacket.PosRot ignored ->
+                moveEntityPacket.getXa() == 0 && moveEntityPacket.getYa() == 0 && moveEntityPacket.getZa() == 0 && moveEntityPacket.getYRot() == 0 && moveEntityPacket.getXRot() == 0;
+            case ClientboundMoveEntityPacket.Rot ignored ->
+                moveEntityPacket.getYRot() == 0 && moveEntityPacket.getXRot() == 0;
+            default -> false;
+        };
+    }
+    // Purpur end
+
     private void handleMinecartPosRot(NewMinecartBehavior behavior, byte yRot, byte xRot, boolean dirty) {
         this.sendDirtyEntityData();
         if (behavior.lerpSteps.isEmpty()) {