Paper/patches/server/0915-Reduce-allocation-of-Vec3D-by-entity-tracker.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
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/network/protocol/game/VecDeltaCodec.java b/src/main/java/net/minecraft/network/protocol/game/VecDeltaCodec.java
index a043ac10834562d357ef0b5aded2e916e2a0d056..74276c368016fcc4dbf9579b2ecbadc9614baf15 100644
--- a/src/main/java/net/minecraft/network/protocol/game/VecDeltaCodec.java
+++ b/src/main/java/net/minecraft/network/protocol/game/VecDeltaCodec.java
@@ -5,7 +5,7 @@ import org.jetbrains.annotations.VisibleForTesting;
 
 public class VecDeltaCodec {
     private static final double TRUNCATION_STEPS = 4096.0;
-    private Vec3 base = Vec3.ZERO;
+    public Vec3 base = Vec3.ZERO; // Paper
 
     @VisibleForTesting
     static long encode(double value) {
diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index 29a28e160f6ca87d263b84fbf0c5429d30e34a21..a43eef8bf05855270601761494b6a67dc55cb1c9 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -1578,10 +1578,14 @@ 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());
+                // Paper start - remove allocation of Vec3D here
+                // Vec3 vec3d = player.position().subtract(this.entity.position());
+                double vec3d_dx = player.getX() - this.entity.getX();
+                double vec3d_dz = player.getZ() - this.entity.getZ();
+                // Paper end - remove allocation of Vec3D here
                 int i = ChunkMap.this.getPlayerViewDistance(player);
                 double d0 = (double) Math.min(this.getEffectiveRange(), i * 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;
                 // Paper start - Configurable entity tracking range by Y
                 boolean flag = d1 <= d2;
diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
index 7118e1f806af98159ec292f9340d7e4004e2b486..f3456aeeab7eee5b6d0383a4bf1338dd8cc95bb3 100644
--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
@@ -178,7 +178,13 @@ public class ServerEntity {
 
                     ++this.teleportDelay;
                     Vec3 vec3d = this.entity.trackingPosition();
-                    boolean flag1 = this.positionCodec.delta(vec3d).lengthSqr() >= 7.62939453125E-6D;
+                    // Paper start - reduce allocation of Vec3D here
+                    Vec3 base = this.positionCodec.base;
+                    double vec3d_dx = vec3d.x - base.x;
+                    double vec3d_dy = vec3d.y - base.y;
+                    double vec3d_dz = vec3d.z - base.z;
+                    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 = false;