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/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
index a7a44fa556a41512d6a76626618afceccd139c64..41802175e4b621fc330abec67274c547851646b3 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -243,6 +243,8 @@ public class ServerEntity {
                         flag4 = true;
                     }
 
+                    if (org.dreeam.leaf.config.modules.opt.ReduceUselessPackets.reduceUselessEntityMovePackets && isUselessMoveEntityPacket(packet1)) packet1 = null; // Purpur
+
                     if ((this.trackDelta || this.entity.hasImpulse || this.entity instanceof LivingEntity && ((LivingEntity) this.entity).isFallFlying()) && this.tickCount > 0) {
                         Vec3 vec3d1 = this.entity.getDeltaMovement();
                     if (vec3d1 != this.lastSentMovement) { // SparklyPaper start - skip distanceToSqr call in ServerEntity#sendChanges if the delta movement hasn't changed
@@ -349,6 +351,27 @@ public class ServerEntity {
         });
     }
 
+    // Purpur start
+    private boolean isUselessMoveEntityPacket(@Nullable Packet<?> packet) {
+        if (packet instanceof ClientboundMoveEntityPacket moveEntityPacket) {
+            switch (packet) {
+                case ClientboundMoveEntityPacket.Pos pos -> {
+                    return moveEntityPacket.getXa() == 0 && moveEntityPacket.getYa() == 0 && moveEntityPacket.getZa() == 0;
+                }
+                case ClientboundMoveEntityPacket.PosRot posRot -> {
+                    return moveEntityPacket.getXa() == 0 && moveEntityPacket.getYa() == 0 && moveEntityPacket.getZa() == 0 && moveEntityPacket.getyRot() == 0 && moveEntityPacket.getxRot() == 0;
+                }
+                case ClientboundMoveEntityPacket.Rot rot -> {
+                    return moveEntityPacket.getyRot() == 0 && moveEntityPacket.getxRot() == 0;
+                }
+                default -> {
+                }
+            }
+        }
+        return false;
+    }
+    // Purpur end
+
     public void removePairing(ServerPlayer player) {
         this.entity.stopSeenByPlayer(player);
         player.connection.send(new ClientboundRemoveEntitiesPacket(new int[]{this.entity.getId()}));
diff --git a/src/main/java/org/dreeam/leaf/config/modules/opt/ReduceUselessPackets.java b/src/main/java/org/dreeam/leaf/config/modules/opt/ReduceUselessPackets.java
new file mode 100644
index 0000000000000000000000000000000000000000..1598298420dbfa6a2611826a4a499a41cfc3740a
--- /dev/null
+++ b/src/main/java/org/dreeam/leaf/config/modules/opt/ReduceUselessPackets.java
@@ -0,0 +1,18 @@
+package org.dreeam.leaf.config.modules.opt;
+
+import org.dreeam.leaf.config.ConfigModules;
+import org.dreeam.leaf.config.EnumConfigCategory;
+
+public class ReduceUselessPackets extends ConfigModules {
+
+    public String getBasePath() {
+        return EnumConfigCategory.PERF.getBaseKeyName() + ".reduce-packets";
+    }
+
+    public static boolean reduceUselessEntityMovePackets = false;
+
+    @Override
+    public void onLoaded() {
+        reduceUselessEntityMovePackets = config.getBoolean(getBasePath() + ".reduce-entity-move-packets", reduceUselessEntityMovePackets);
+    }
+}