SparklyPaperMC/patches/server/0004-Skip-distanceToSqr-call-in-ServerEntity-sendChanges-.patch

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] Skip "distanceToSqr" call in "ServerEntity#sendChanges" if
 the delta movement hasn't changed

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/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
index 9938d359de5b179ff486390288d481d6ece1ecf3..ff5bf212e194dd0914c06e636a8268e8e8f6fff8 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -243,6 +243,7 @@ public class ServerEntity {
 
                     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
                         double d0 = vec3d1.distanceToSqr(this.lastSentMovement);
 
                         if (d0 > 1.0E-7D || d0 > 0.0D && vec3d1.lengthSqr() == 0.0D) {
@@ -257,6 +258,7 @@ public class ServerEntity {
                                 this.broadcast.accept(new ClientboundSetEntityMotionPacket(this.entity.getId(), this.lastSentMovement));
                             }
                         }
+                    } // SparklyPaper end
                     }
 
                     if (packet1 != null) {