Paper/patches/server/0431-Reduce-allocation-of-Vec3D-by-entity-tracker.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <spottedleaf@spottedleaf.dev>
Date: Mon, 27 Apr 2020 00:04:16 -0700
Subject: [PATCH] Reduce allocation of Vec3D by entity tracker


diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index 49e612fc0fc4ec991d821d0aa4b41f488dd9f832..62a8482b73796f2c6b76c0e039cb21e799bc9416 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -1826,9 +1826,13 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         public void updatePlayer(ServerPlayer player) {
             org.spigotmc.AsyncCatcher.catchOp("player tracker update"); // Spigot
             if (player != this.entity) {
-                Vec3 vec3d = player.position().subtract(this.entity.position()); // MC-155077, SPIGOT-5113
+                // Paper start - remove allocation of Vec3D here
+                //Vec3 vec3d = player.position().subtract(this.entity.position()); // MC-155077, SPIGOT-5113
+                double vec3d_dx = player.getX() - this.entity.getX();
+                double vec3d_dz = player.getZ() - this.entity.getZ();
+                // Paper end - remove allocation of Vec3D here
                 double d0 = (double) Math.min(this.getEffectiveRange(), (ChunkMap.this.viewDistance - 1) * 16);
-                double d1 = vec3d.x * vec3d.x + vec3d.z * vec3d.z;
+                double d1 = vec3d_dx * vec3d_dx + vec3d_dz * vec3d_dz; // Paper
                 double d2 = d0 * d0;
                 boolean flag = d1 <= d2 && this.entity.broadcastToPlayer(player);
 
diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
index ceba19ea3bb9664899b83f82f28af06476b7ff56..f6b6ac1ab31c364646151866c54c9e46dee12516 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -143,8 +143,12 @@ public class ServerEntity {
                 ++this.teleportDelay;
                 i = Mth.floor(this.entity.getYRot() * 256.0F / 360.0F);
                 j = Mth.floor(this.entity.getXRot() * 256.0F / 360.0F);
-                Vec3 vec3d = this.entity.position().subtract(ClientboundMoveEntityPacket.packetToEntity(this.xp, this.yp, this.zp));
-                boolean flag1 = vec3d.lengthSqr() >= 7.62939453125E-6D;
+                // Paper start - reduce allocation of Vec3D here
+                double vec3d_dx = this.entity.getX() - 2.44140625E-4D*(this.xp);
+                double vec3d_dy = this.entity.getY() - 2.44140625E-4D*(this.yp);
+                double vec3d_dz = this.entity.getZ() - 2.44140625E-4D*(this.zp);
+                boolean flag1 = (vec3d_dx * vec3d_dx + vec3d_dy * vec3d_dy + vec3d_dz * vec3d_dz) >= 7.62939453125E-6D;
+                // Paper end - reduce allocation of Vec3D here
                 Packet<?> packet1 = null;
                 boolean flag2 = flag1 || this.tickCount % 60 == 0;
                 boolean flag3 = Math.abs(i - this.yRotp) >= 1 || Math.abs(j - this.xRotp) >= 1;
@@ -161,9 +165,11 @@ public class ServerEntity {
                 // CraftBukkit end
 
                 if (this.tickCount > 0 || this.entity instanceof AbstractArrow) {
-                    long k = ClientboundMoveEntityPacket.entityToPacket(vec3d.x);
-                    long l = ClientboundMoveEntityPacket.entityToPacket(vec3d.y);
-                    long i1 = ClientboundMoveEntityPacket.entityToPacket(vec3d.z);
+                    // Paper start - remove allocation of Vec3D here
+                    long k = ClientboundMoveEntityPacket.entityToPacket(vec3d_dx);
+                    long l = ClientboundMoveEntityPacket.entityToPacket(vec3d_dy);
+                    long i1 = ClientboundMoveEntityPacket.entityToPacket(vec3d_dz);
+                    // Paper end - remove allocation of Vec3D here
                     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()) {