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/EntityTrackerEntry.java b/src/main/java/net/minecraft/server/EntityTrackerEntry.java
index 6d3b34ead9cc95dcc1152dffa8c6c4a8c7f1d58b..5cc89c0cf9e9e632212a9653391437cbe9b15031 100644
--- a/src/main/java/net/minecraft/server/EntityTrackerEntry.java
+++ b/src/main/java/net/minecraft/server/EntityTrackerEntry.java
@@ -125,8 +125,12 @@ public class EntityTrackerEntry {
                 ++this.o;
                 i = MathHelper.d(this.tracker.yaw * 256.0F / 360.0F);
                 j = MathHelper.d(this.tracker.pitch * 256.0F / 360.0F);
-                Vec3D vec3d = this.tracker.getPositionVector().d(PacketPlayOutEntity.a(this.xLoc, this.yLoc, this.zLoc));
-                boolean flag1 = vec3d.g() >= 7.62939453125E-6D;
+                // Paper start - reduce allocation of Vec3D here
+                double vec3d_dx = this.tracker.locX() - 2.44140625E-4D*(this.xLoc);
+                double vec3d_dy = this.tracker.locY() - 2.44140625E-4D*(this.yLoc);
+                double vec3d_dz = this.tracker.locZ() - 2.44140625E-4D*(this.zLoc);
+                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.tickCounter % 60 == 0;
                 boolean flag3 = Math.abs(i - this.yRot) >= 1 || Math.abs(j - this.xRot) >= 1;
@@ -143,9 +147,11 @@ public class EntityTrackerEntry {
                 // CraftBukkit end
 
                 if (this.tickCounter > 0 || this.tracker instanceof EntityArrow) {
-                    long k = PacketPlayOutEntity.a(vec3d.x);
-                    long l = PacketPlayOutEntity.a(vec3d.y);
-                    long i1 = PacketPlayOutEntity.a(vec3d.z);
+                    // Paper start - remove allocation of Vec3D here
+                    long k = PacketPlayOutEntity.a(vec3d_dx);
+                    long l = PacketPlayOutEntity.a(vec3d_dy);
+                    long i1 = PacketPlayOutEntity.a(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.o <= 400 && !this.q && this.r == this.tracker.onGround) {
diff --git a/src/main/java/net/minecraft/server/PlayerChunkMap.java b/src/main/java/net/minecraft/server/PlayerChunkMap.java
index 3cd9e1238d944d77245404de0d926731d9ee4c1a..fa4e27011bde8838729c9f0a812bb68bd05a6169 100644
--- a/src/main/java/net/minecraft/server/PlayerChunkMap.java
+++ b/src/main/java/net/minecraft/server/PlayerChunkMap.java
@@ -2131,9 +2131,14 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
         public void updatePlayer(EntityPlayer entityplayer) {
             org.spigotmc.AsyncCatcher.catchOp("player tracker update"); // Spigot
             if (entityplayer != this.tracker) {
-                Vec3D vec3d = entityplayer.getPositionVector().d(this.tracker.getPositionVector()); // MC-155077, SPIGOT-5113
+                // Paper start - remove allocation of Vec3D here
+                //Vec3D vec3d = entityplayer.getPositionVector().d(this.tracker.getPositionVector()); // MC-155077, SPIGOT-5113
+                double vec3d_dx = entityplayer.locX() - this.tracker.locX();
+                double vec3d_dy = entityplayer.locY() - this.tracker.locY();
+                double vec3d_dz = entityplayer.locZ() - this.tracker.locZ();
+                // Paper end - remove allocation of Vec3D here
                 int i = Math.min(this.b(), (PlayerChunkMap.this.viewDistance - 1) * 16);
-                boolean flag = vec3d.x >= (double) (-i) && vec3d.x <= (double) i && vec3d.z >= (double) (-i) && vec3d.z <= (double) i && this.tracker.a(entityplayer);
+                boolean flag = vec3d_dx >= (double) (-i) && vec3d_dx <= (double) i && vec3d_dz >= (double) (-i) && vec3d_dz <= (double) i && this.tracker.a(entityplayer); // Paper - remove allocation of Vec3D here
 
                 if (flag) {
                     boolean flag1 = this.tracker.attachedToPlayer;