From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: violetc <58360096+s-yh-china@users.noreply.github.com>
Date: Sun, 14 Aug 2022 00:00:51 +0800
Subject: [PATCH] Dont send useless entity packets

This patch is Powered by Purpur(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 190e9761087baec5827d722a8281f0ffb6798341..158da4c3b002a4948bfb214337aa28a55b358fc9 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -170,20 +170,29 @@ public class ServerEntity {
                     boolean flag4 = k < -32768L || k > 32767L || l < -32768L || l > 32767L || i1 < -32768L || i1 > 32767L;
 
                     if (!flag4 && this.teleportDelay <= 400 && !this.wasRiding && this.wasOnGround == this.entity.isOnGround() && !(io.papermc.paper.configuration.GlobalConfiguration.get().collisions.sendFullPosForHardCollidingEntities && this.entity.hardCollides())) { // Paper - send full pos for hard colliding entities to prevent collision problems due to desync
-                        if ((!flag2 || !flag3) && !(this.entity instanceof AbstractArrow)) {
-                            if (flag2) {
-                                packet1 = new ClientboundMoveEntityPacket.Pos(this.entity.getId(), (short) ((int) k), (short) ((int) l), (short) ((int) i1), this.entity.isOnGround());
-                            } else if (flag3) {
-                                packet1 = new ClientboundMoveEntityPacket.Rot(this.entity.getId(), (byte) i, (byte) j, this.entity.isOnGround());
+                        // Leaves start - Better checking
+                        if (flag2 || flag3 || this.entity instanceof AbstractArrow) {
+                            if ((!flag2 || !flag3) && !(this.entity instanceof AbstractArrow)) {
+                                if (flag2) {
+                                    packet1 = new ClientboundMoveEntityPacket.Pos(this.entity.getId(), (short) ((int) k), (short) ((int) l), (short) ((int) i1), this.entity.isOnGround());
+                                } else if (flag3) {
+                                    packet1 = new ClientboundMoveEntityPacket.Rot(this.entity.getId(), (byte) i, (byte) j, this.entity.isOnGround());
+                                }
+                            } else {
+                                packet1 = new ClientboundMoveEntityPacket.PosRot(this.entity.getId(), (short) ((int) k), (short) ((int) l), (short) ((int) i1), (byte) i, (byte) j, this.entity.isOnGround());
                             }
-                        } else {
-                            packet1 = new ClientboundMoveEntityPacket.PosRot(this.entity.getId(), (short) ((int) k), (short) ((int) l), (short) ((int) i1), (byte) i, (byte) j, this.entity.isOnGround());
                         }
+                        // Leaves end - Better checking
                     } else {
                         this.wasOnGround = this.entity.isOnGround();
                         this.teleportDelay = 0;
                         packet1 = new ClientboundTeleportEntityPacket(this.entity);
                     }
+                    // Leaves start - dont send useless entity packets
+                    if (top.leavesmc.leaves.LeavesConfig.dontSendUselessEntityPackets && isUselessPacket(packet1)) {
+                        packet1 = null;
+                    }
+                    // Leaves end - dont send useless entity packets
                 }
 
                 if ((this.trackDelta || this.entity.hasImpulse || this.entity instanceof LivingEntity && ((LivingEntity) this.entity).isFallFlying()) && this.tickCount > 0) {
@@ -250,6 +259,21 @@ public class ServerEntity {
 
     }
 
+    // Leaves start - dont send useless entity packets
+    private boolean isUselessPacket(Packet<?> possibleUselessPacket) {
+        if (possibleUselessPacket instanceof ClientboundMoveEntityPacket packet) {
+            if (possibleUselessPacket instanceof ClientboundMoveEntityPacket.Pos) {
+                return packet.getXa() == 0 && packet.getYa() == 0 && packet.getZa() == 0;
+            } else if (possibleUselessPacket instanceof ClientboundMoveEntityPacket.PosRot) {
+                return packet.getXa() == 0 && packet.getYa() == 0 && packet.getZa() == 0 && packet.getyRot() == 0 && packet.getxRot() == 0;
+            } else if (possibleUselessPacket instanceof ClientboundMoveEntityPacket.Rot) {
+                return packet.getyRot() == 0 && packet.getxRot() == 0;
+            }
+        }
+        return false;
+    }
+    // Leaves end - dont send useless entity packets
+
     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/top/leavesmc/leaves/LeavesConfig.java b/src/main/java/top/leavesmc/leaves/LeavesConfig.java
index c48c2cbe2d3fcbed78c273c36802b27dbaa2da38..e8308375c91cdb136f1611baaf108c9078365331 100644
--- a/src/main/java/top/leavesmc/leaves/LeavesConfig.java
+++ b/src/main/java/top/leavesmc/leaves/LeavesConfig.java
@@ -230,6 +230,11 @@ public final class LeavesConfig {
         }
     }
 
+    public static boolean dontSendUselessEntityPackets = true;
+    private static void dontSendUselessEntityPackets() {
+        dontSendUselessEntityPackets = getBoolean("settings.performance.dont-send-useless-entity-packets", dontSendUselessEntityPackets);
+    }
+
     public static final class WorldConfig {
 
         public final String worldName;