From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Martijn Muijsers <martijnmuijsers@live.nl>
Date: Wed, 30 Aug 2023 20:01:31 +0200
Subject: [PATCH] Reduce line of sight updates and cache lookups

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:
"feat: reduce sensor work"
By: peaches94 <peachescu94@gmail.com>
As part of: Petal (https://github.com/Bloom-host/Petal)
Licensed under: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html)

* Petal description *

this patch is focused around the sensors used for ai
delete the line of sight cache less often and use a faster nearby comparison

diff --git a/src/main/java/net/minecraft/world/entity/ai/sensing/Sensing.java b/src/main/java/net/minecraft/world/entity/ai/sensing/Sensing.java
index 57472cb54e9fd83e980e3c57f28d6e6643f422e8..ce50852a9b18679a80e9393e8d904935917e0439 100644
--- a/src/main/java/net/minecraft/world/entity/ai/sensing/Sensing.java
+++ b/src/main/java/net/minecraft/world/entity/ai/sensing/Sensing.java
@@ -1,39 +1,81 @@
 package net.minecraft.world.entity.ai.sensing;
 
-import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
-import it.unimi.dsi.fastutil.ints.IntSet;
+import it.unimi.dsi.fastutil.ints.Int2IntMap;
+import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
+import it.unimi.dsi.fastutil.ints.IntArrayList;
+import it.unimi.dsi.fastutil.ints.IntList;
 import net.minecraft.world.entity.Entity;
 import net.minecraft.world.entity.Mob;
+import org.galemc.gale.configuration.GaleGlobalConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public class Sensing {
     private final Mob mob;
-    // Gale start - initialize line of sight cache with low capacity
-    private final IntSet seen = new IntOpenHashSet(2);
-    private final IntSet unseen = new IntOpenHashSet(2);
-    // Gale end - initialize line of sight cache with low capacity
+    private final Int2IntMap seen = new Int2IntOpenHashMap(2); // Gale end - initialize line of sight cache with low capacity // Gale - Petal - reduce line of sight cache lookups - merge sets
+
+    // Gale start - Petal - reduce line of sight updates - expiring entity id lists
+    private final @NotNull IntList @Nullable [] expiring;
+    private int currentCacheAddIndex = 0;
+    private int nextToExpireIndex = 1;
+    // Gale end - Petal - reduce line of sight updates - expiring entity id lists
 
     public Sensing(Mob owner) {
         this.mob = owner;
+        // Gale start - Petal - reduce line of sight updates - expiring entity id lists
+        int updateLineOfSightInterval = GaleGlobalConfiguration.get().smallOptimizations.reducedIntervals.updateEntityLineOfSight;
+        if (updateLineOfSightInterval <= 1) {
+            this.expiring = null;
+        } else {
+            this.expiring = new IntList[updateLineOfSightInterval];
+            for (int i = 0; i < updateLineOfSightInterval; i++) {
+                this.expiring[i] = new IntArrayList(0);
+            }
+        }
+        // Gale end - Petal - reduce line of sight updates - expiring entity id lists
     }
 
     public void tick() {
+        if (this.expiring == null) { // Gale - Petal - reduce line of sight updates
         this.seen.clear();
-        this.unseen.clear();
+        // Gale start - Petal - reduce line of sight updates
+        } else {
+            var expiringNow = this.expiring[this.nextToExpireIndex];
+            expiringNow.forEach(this.seen::remove);
+            expiringNow.clear();
+            this.currentCacheAddIndex++;
+            if (this.currentCacheAddIndex == this.expiring.length) {
+                this.currentCacheAddIndex = 0;
+            }
+            this.nextToExpireIndex++;
+            if (this.nextToExpireIndex == this.expiring.length) {
+                this.nextToExpireIndex = 0;
+            }
+        }
+        // Gale end - Petal - reduce line of sight updates
     }
 
     public boolean hasLineOfSight(Entity entity) {
         int i = entity.getId();
-        if (this.seen.contains(i)) {
+        // Gale start - Petal - reduce line of sight cache lookups - merge sets
+        int cached = this.seen.get(i);
+        if (cached == 1) {
+            // Gale end - Petal - reduce line of sight cache lookups - merge sets
             return true;
-        } else if (this.unseen.contains(i)) {
+        } else if (cached == 2) { // Gale - Petal - reduce line of sight cache lookups - merge sets
             return false;
         } else {
             boolean bl = this.mob.hasLineOfSight(entity);
             if (bl) {
-                this.seen.add(i);
+                this.seen.put(i, 1); // Gale - Petal - reduce line of sight cache lookups - merge sets
             } else {
-                this.unseen.add(i);
+                this.seen.put(i, 2); // Gale - Petal - reduce line of sight cache lookups - merge sets
+            }
+            // Gale start - Petal - reduce line of sight updates
+            if (this.expiring != null) {
+                this.expiring[this.currentCacheAddIndex].add(i);
             }
+            // Gale end - Petal - reduce line of sight updates
 
             return bl;
         }
diff --git a/src/main/java/org/galemc/gale/configuration/GaleGlobalConfiguration.java b/src/main/java/org/galemc/gale/configuration/GaleGlobalConfiguration.java
index c57ebf0f37aba2d118e54f3c71697f29bb9a57a0..417dda8dc61af144fe07963b66080e5c9f2750b4 100644
--- a/src/main/java/org/galemc/gale/configuration/GaleGlobalConfiguration.java
+++ b/src/main/java/org/galemc/gale/configuration/GaleGlobalConfiguration.java
@@ -34,6 +34,7 @@ public class GaleGlobalConfiguration extends ConfigurationPart {
         public class ReducedIntervals extends ConfigurationPart {
 
             public int increaseTimeStatistics = 20; // Gale - Hydrinity - increase time statistics in intervals
+            public int updateEntityLineOfSight = 4; // Gale - Petal - reduce line of sight updates
 
             @PostProcess
             public void postProcess() {