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 4fd889d717a22c84ebd092d80739c6e7f1fb8534..a7f0c7c0618f004315570801334d52ce3ec4b4e2 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 55306f3aaed98307ed0ac662351d18e274095a01..ec0c8205959d451c5f8c15f0aa11d0115f1d8125 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;