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 2d11a67bdc82088abf0b3ca134f352f155c8eb1f..a31d7c1907f40792eefe35038bc6ec7cb67b2f6a 100644
--- a/src/main/java/io/papermc/paper/util/MCUtil.java
+++ b/src/main/java/io/papermc/paper/util/MCUtil.java
@@ -210,7 +210,7 @@ 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 6c4f536601c36730061310ee028da7adeaf2737e..47bcb134acdaa8d36a0544dae15f12ea47e143dd 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;