From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Martijn Muijsers <martijnmuijsers@live.nl>
Date: Wed, 23 Nov 2022 23:32:51 +0100
Subject: [PATCH] Optimize entity coordinate key

License: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html)
Gale - https://galemc.org

This patch is based on the following patch:
"Optimize entity coordinate key"
By: Kevin Raneri <kevin.raneri@gmail.com>
As part of: Pufferfish (https://github.com/pufferfish-gg/Pufferfish)
Licensed under: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html)

* Pufferfish description *

When executing getCoordinateKey for entities (a hotpath), the JVM is
required to repeatedly cast doubles to longs. The performance impact of
this depends on the CPU architecture, but generally switching between
FPU and ALU incurs a significant performance hit. The casted/rounded
data is already available in the blockPosition struct, so we use that
instead of re-doing the casting.

diff --git a/src/main/java/io/papermc/paper/util/MCUtil.java b/src/main/java/io/papermc/paper/util/MCUtil.java
index cb4379268b191d331c71be44642baac381ffaaf6..77aa75c9b1c31b47513a9d06b0930f9524a3d6d1 100644
--- a/src/main/java/io/papermc/paper/util/MCUtil.java
+++ b/src/main/java/io/papermc/paper/util/MCUtil.java
@@ -211,7 +211,7 @@ public final class MCUtil {
     }
 
     public static long getCoordinateKey(final Entity entity) {
-        return ((long)(MCUtil.fastFloor(entity.getZ()) >> 4) << 32) | ((MCUtil.fastFloor(entity.getX()) >> 4) & 0xFFFFFFFFL);
+        return ((long)(entity.blockPosition.getZ() >> 4) << 32) | ((entity.blockPosition.getX() >> 4) & 0xFFFFFFFFL); // Gale - Pufferfish - optimize entity coordinate key - eliminate double->long cast in hotpath
     }
 
     public static long getCoordinateKey(final ChunkPos pair) {
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index d1ee75ec070ac6f08f120c14c68a02f529d33174..d2a8f3260141af6a8bb807bdd581f7c3d5a7dca5 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -306,7 +306,7 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
     public double yo;
     public double zo;
     private Vec3 position;
-    private BlockPos blockPosition;
+    public BlockPos blockPosition; // Gale - Pufferfish - optimize entity coordinate key - private -> public
     private ChunkPos chunkPosition;
     private Vec3 deltaMovement;
     private float yRot;