From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: MrPowerGamerBR <git@mrpowergamerbr.com>
Date: Wed, 15 Nov 2023 23:39:36 -0300
Subject: [PATCH] SparklyPaper: Skip "distanceToSqr" call in
 "ServerEntity#sendChanges" if the delta movement hasn't changed

Original project: https://github.com/SparklyPower/SparklyPaper

The "distanceToSqr" call is a bit expensive, so avoiding it is pretty nice, around ~15% calls are skipped with this check

We could also check if the x,y,z coordinates are equal, but for now, let's just keep the identity check, which also helps us since Minecraft's code does reuse the original delta movement Vec3 object

diff --git a/net/minecraft/server/level/ServerEntity.java b/net/minecraft/server/level/ServerEntity.java
index d985555a029d06ffc73dd10115df47b83c9afafd..ddf2a5e2cfeaa666a081dd857d6a6003d65d0e00 100644
--- a/net/minecraft/server/level/ServerEntity.java
+++ b/net/minecraft/server/level/ServerEntity.java
@@ -201,6 +201,7 @@ 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;
@@ -218,6 +219,7 @@ public class ServerEntity {
                             this.broadcast.accept(new ClientboundSetEntityMotionPacket(this.entity.getId(), this.lastSentMovement));
                         }
                     }
+                    } // SparklyPaper end
                 }
 
                 if (packet != null) {