From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: HaHaWTH <102713261+HaHaWTH@users.noreply.github.com>
Date: Fri, 29 Oct 2077 00:00:00 +0800
Subject: [PATCH] Optimize Entity distanceToSqr

This patch optimizes Entity#distanceToSqr call by using Math#fma which is around 1.2x to 4x faster than original method,
avoids multiple casting in Entity#distanceTo, using Math#sqrt directly instead of Mojang's Mth#sqrt. Additionally, this patch makes
these methods more able to be inlined by the JIT compiler.

diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 08a3714c530fb375ee729e91965c65efb9e6e3d2..6a19390aff7c8f7170467d2c6306b00779f23082 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -2368,33 +2368,41 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         this.xRotO = this.getXRot();
     }
 
-    public float distanceTo(Entity entity) {
-        float f = (float) (this.getX() - entity.getX());
-        float f1 = (float) (this.getY() - entity.getY());
-        float f2 = (float) (this.getZ() - entity.getZ());
+    // Leaf start - Optimize distanceTo - inlining
+    public final float distanceTo(Entity entity) {
+        // Leaf start - Optimize distanceTo - Avoid casting
+        final double dx = this.getX() - entity.getX();
+        final double dy = this.getY() - entity.getY();
+        final double dz = this.getZ() - entity.getZ();
+        // Leaf end - Optimize distanceTo - Avoid casting
 
-        return Mth.sqrt(f * f + f1 * f1 + f2 * f2);
+        return (float) Math.sqrt(org.dreeam.leaf.LeafBootstrap.enableFMA ? Math.fma(dx, dx, Math.fma(dy, dy, dz * dz)) : dx * dx + dy * dy + dz * dz); // Leaf - Use Math#sqrt instead of Mojang's Mth#sqrt - only cast once
     }
+    // Leaf end - Optimize distanceTo - inlining
 
-    public double distanceToSqr(double x, double y, double z) {
-        double d3 = this.getX() - x;
-        double d4 = this.getY() - y;
-        double d5 = this.getZ() - z;
+    // Leaf start - Optimize distanceToSqr - inlining
+    public final double distanceToSqr(final double x, final double y, final double z) {
+        final double dx = this.getX() - x;
+        final double dy = this.getY() - y;
+        final double dz = this.getZ() - z;
 
-        return d3 * d3 + d4 * d4 + d5 * d5;
+        return org.dreeam.leaf.LeafBootstrap.enableFMA ? Math.fma(dx, dx, Math.fma(dy, dy, dz * dz)) : dx * dx + dy * dy + dz * dz; // Leaf - Use FMA for distanceToSqr
     }
+    // Leaf end - Optimize distanceToSqr
 
     public double distanceToSqr(Entity entity) {
         return this.distanceToSqr(entity.position());
     }
 
-    public double distanceToSqr(Vec3 vector) {
-        double d0 = this.getX() - vector.x;
-        double d1 = this.getY() - vector.y;
-        double d2 = this.getZ() - vector.z;
+    // Leaf start - Optimize distanceToSqr - inlining
+    public final double distanceToSqr(Vec3 vector) {
+        final double dx = this.getX() - vector.x;
+        final double dy = this.getY() - vector.y;
+        final double dz = this.getZ() - vector.z;
 
-        return d0 * d0 + d1 * d1 + d2 * d2;
+        return org.dreeam.leaf.LeafBootstrap.enableFMA ? Math.fma(dx, dx, Math.fma(dy, dy, dz * dz)) : dx * dx + dy * dy + dz * dz; // Leaf - Use FMA for distanceToSqr
     }
+    // Leaf end - Optimize distanceToSqr - inlining
 
     public void playerTouch(Player player) {}
 
diff --git a/src/main/java/org/dreeam/leaf/LeafBootstrap.java b/src/main/java/org/dreeam/leaf/LeafBootstrap.java
index 2f5122a61af183d6a4c20a175122c228b6e9fc48..9055727c16659ae43eb5424f0aa61e419f53483e 100644
--- a/src/main/java/org/dreeam/leaf/LeafBootstrap.java
+++ b/src/main/java/org/dreeam/leaf/LeafBootstrap.java
@@ -4,6 +4,7 @@ import io.papermc.paper.PaperBootstrap;
 import joptsimple.OptionSet;
 
 public class LeafBootstrap {
+    public static final boolean enableFMA = Boolean.parseBoolean(System.getProperty("Leaf.enableFMA", "false")); // Leaf - FMA feature
 
     public static void boot(final OptionSet options) {
         runPreBootTasks();