From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: MrHua269 <wangxyper@163.com>
Date: Sun, 12 Jan 2025 15:37:25 +0800
Subject: [PATCH] SparklyPaper: Skip "distanceToSqr" call in
 "ServerEntity#sendChanges" if the delta movement hasn't changed

Co-authored by: MrPowerGamerBR <git@mrpowergamerbr.com>
As part of: SparklyPaper (https://github.com/SparklyPower/SparklyPaper/blob/a69d3690472c9967772ffd4d4bd1f41403b7ea6f/sparklypaper-server/minecraft-patches/features/0002-Skip-distanceToSqr-call-in-ServerEntity-sendChanges-.patch)

diff --git a/net/minecraft/server/level/ServerEntity.java b/net/minecraft/server/level/ServerEntity.java
index 2d4c68b01cc1508a1a4715a91316a7db80d4efa2..3a9293d5328ef0befa0b709169489b61a2266807 100644
--- a/net/minecraft/server/level/ServerEntity.java
+++ b/net/minecraft/server/level/ServerEntity.java
@@ -209,6 +209,8 @@ public class ServerEntity {
 
                 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
                     double d = deltaMovement.distanceToSqr(this.lastSentMovement);
                     if (d > 1.0E-7 || d > 0.0 && deltaMovement.lengthSqr() == 0.0) {
                         this.lastSentMovement = deltaMovement;
@@ -226,6 +228,7 @@ public class ServerEntity {
                             this.broadcast.accept(new ClientboundSetEntityMotionPacket(this.entity.getId(), this.lastSentMovement));
                         }
                     }
+                    } // SparklyPaper end
                 }
 
                 if (packet != null) {