From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Martijn Muijsers <martijnmuijsers@live.nl>
Date: Sun, 25 Dec 2022 20:29:03 +0100
Subject: [PATCH] Skip unnecessary mob spawning computations

Removed since Leaf 1.21.5, can be replaced by other optimizations

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:
"Only create a spawner state when we are actually spawning mobs"
By: PureGero <puregero@gmail.com>
As part of: MultiPaper (https://github.com/MultiPaper/MultiPaper)
Licensed under: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html)

diff --git a/net/minecraft/server/level/ServerChunkCache.java b/net/minecraft/server/level/ServerChunkCache.java
index 5c8d76b80c6cefd87088282e59f5f0f72a4f1611..7a18b11782b2524280fddf20e6b1cabdddf07c49 100644
--- a/net/minecraft/server/level/ServerChunkCache.java
+++ b/net/minecraft/server/level/ServerChunkCache.java
@@ -550,9 +550,15 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
     }
 
     private void tickChunks(long timeInhabited, List<LevelChunk> chunks) { // Gale - Purpur - remove vanilla profiler
+        // Gale start - MultiPaper - skip unnecessary mob spawning computations
+        NaturalSpawner.SpawnState spawnState; // moved down
+        final boolean _boolean = this.level.getGameRules().getBoolean(GameRules.RULE_DOMOBSPAWNING) && !this.level.players().isEmpty(); // CraftBukkit
+        boolean flagAndHasNaturalSpawn = _boolean && this.anySpawnCategoryIsSpawnedThisTick();
+
+        if (flagAndHasNaturalSpawn) {
+            // Gale end - MultiPaper - skip unnecessary mob spawning computations
         int naturalSpawnChunkCount = this.distanceManager.getNaturalSpawnChunkCount();
         // Paper start - Optional per player mob spawns
-        NaturalSpawner.SpawnState spawnState;
         if ((this.spawnFriendlies || this.spawnEnemies) && this.level.paperConfig().entities.spawning.perPlayerMobSpawns) { // don't count mobs when animals and monsters are disabled
             // re-set mob counts
             for (ServerPlayer player : this.level.players) {
@@ -574,10 +580,14 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
         }
         // Paper end - Optional per player mob spawns
         this.lastSpawnState = spawnState;
-        boolean _boolean = this.level.getGameRules().getBoolean(GameRules.RULE_DOMOBSPAWNING) && !this.level.players().isEmpty(); // CraftBukkit
+            // Gale start - MultiPaper - skip unnecessary mob spawning computations
+        } else {
+            spawnState = null;
+        }
+        // Gale end - MultiPaper - skip unnecessary mob spawning computations
         int _int = this.level.getGameRules().getInt(GameRules.RULE_RANDOMTICKING);
         List<MobCategory> filteredSpawningCategories;
-        if (_boolean && (this.spawnEnemies || this.spawnFriendlies)) {
+        if (flagAndHasNaturalSpawn && (this.spawnEnemies || this.spawnFriendlies)) { // Gale - MultiPaper - skip unnecessary mob spawning computations
             // Paper start - PlayerNaturallySpawnCreaturesEvent
             for (ServerPlayer entityPlayer : this.level.players()) {
                 int chunkRange = Math.min(level.spigotConfig.mobSpawnRange, entityPlayer.getBukkitEntity().getViewDistance());
@@ -604,11 +614,25 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
             }
         }
 
-        if (_boolean) {
+        if (flagAndHasNaturalSpawn) { // Gale - MultiPaper - skip unnecessary mob spawning computations
             this.level.tickCustomSpawners(this.spawnEnemies, this.spawnFriendlies);
         }
     }
 
+    // Gale start - MultiPaper - skip unnecessary mob spawning computations
+    private boolean anySpawnCategoryIsSpawnedThisTick() {
+        long gameTime = this.level.getLevelData().getGameTime();
+
+        for (long ticksForSpawnCategory : this.level.ticksPerSpawnCategory.values()) {
+            if (ticksForSpawnCategory != 0L && gameTime % ticksForSpawnCategory == 0L) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+    // Gale end - MultiPaper - skip unnecessary mob spawning computations
+
     private void getFullChunk(long chunkPos, Consumer<LevelChunk> fullChunkGetter) {
         // Paper start - rewrite chunk system
         // note: bypass currentlyLoaded from getChunkNow