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/net/minecraft/world/entity/Entity.java b/net/minecraft/world/entity/Entity.java
index d544d66542d53db1a847a6b1ab8cf5ee848f31de..e563b636a05a299d860a334987594dbd5c7d3511 100644
--- a/net/minecraft/world/entity/Entity.java
+++ b/net/minecraft/world/entity/Entity.java
@@ -394,6 +394,7 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
     private int sectionY = Integer.MIN_VALUE;
     private int sectionZ = Integer.MIN_VALUE;
     private boolean updatingSectionStatus;
+    private static final boolean enableFMA = Boolean.getBoolean("Leaf.enableFMA"); // Leaf - Optimize Entity distanceTo
 
     @Override
     public final boolean moonrise$isHardColliding() {
@@ -2260,31 +2261,6 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         return new Vec3(this.xOld, this.yOld, this.zOld);
     }
 
-    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());
-        return Mth.sqrt(f * f + f1 * f1 + f2 * f2);
-    }
-
-    public double distanceToSqr(double x, double y, double z) {
-        double d = this.getX() - x;
-        double d1 = this.getY() - y;
-        double d2 = this.getZ() - z;
-        return d * d + d1 * d1 + d2 * d2;
-    }
-
-    public double distanceToSqr(Entity entity) {
-        return this.distanceToSqr(entity.position());
-    }
-
-    public double distanceToSqr(Vec3 vec) {
-        double d = this.getX() - vec.x;
-        double d1 = this.getY() - vec.y;
-        double d2 = this.getZ() - vec.z;
-        return d * d + d1 * d1 + d2 * d2;
-    }
-
     public void playerTouch(Player player) {
     }
 
@@ -5509,4 +5485,34 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         return false;
     }
     // Purpur end - Ridables
+
+    // Leaf start - Optimize Entity distanceTo
+    // Inlining and avoid casting
+    // Use Math#sqrt instead of Mojang's Mth#sqrt - only cast once
+    // Added option to enable FMA acceleration
+    public final float distanceTo(Entity entity) {
+        final double dx = this.getX() - entity.getX();
+        final double dy = this.getY() - entity.getY();
+        final double dz = this.getZ() - entity.getZ();
+        return (float) Math.sqrt(enableFMA ? Math.fma(dx, dx, Math.fma(dy, dy, dz * dz)) : dx * dx + dy * dy + dz * dz);
+    }
+
+    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 enableFMA ? Math.fma(dx, dx, Math.fma(dy, dy, dz * dz)) : dx * dx + dy * dy + dz * dz;
+    }
+
+    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 enableFMA ? Math.fma(dx, dx, Math.fma(dy, dy, dz * dz)) : dx * dx + dy * dy + dz * dz;
+    }
+
+    public double distanceToSqr(Entity entity) {
+        return this.distanceToSqr(entity.position());
+    }
+    // Leaf end - Optimize Entity distanceToSqr
 }