From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 14 Jan 2018 17:36:02 -0500
Subject: [PATCH] PlayerNaturallySpawnCreaturesEvent

This event can be used for when you want to exclude a certain player
from triggering monster spawns on a server.

Also a highly more effecient way to blanket block spawns in a world

diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index 4c0eb0dbb5caff7944e7bdde803a9eb66d7631be..6352e3f0a78822b4d5167a688a5230b599541159 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -1193,7 +1193,9 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         chunkRange = (chunkRange > level.spigotConfig.viewDistance) ? (byte) level.spigotConfig.viewDistance : chunkRange;
         chunkRange = (chunkRange > 8) ? 8 : chunkRange;
 
-        double blockRange = (reducedRange) ? Math.pow(chunkRange << 4, 2) : 16384.0D;
+        final int finalChunkRange = chunkRange; // Paper for lambda below
+        //double blockRange = (reducedRange) ? Math.pow(chunkRange << 4, 2) : 16384.0D; // Paper - use from event
+        double blockRange = 16384.0D; // Paper
         // Spigot end
         if (!this.distanceManager.hasPlayersNearby(chunkcoordintpair.toLong())) {
             return false;
@@ -1208,6 +1210,15 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
                 }
 
                 entityplayer = (ServerPlayer) iterator.next();
+                // Paper start - add PlayerNaturallySpawnCreaturesEvent
+                com.destroystokyo.paper.event.entity.PlayerNaturallySpawnCreaturesEvent event;
+                blockRange = 16384.0D;
+                if (reducedRange) {
+                    event = entityplayer.playerNaturallySpawnedEvent;
+                    if (event == null || event.isCancelled()) return false;
+                    blockRange = (double) ((event.getSpawnRadius() << 4) * (event.getSpawnRadius() << 4));
+                }
+                // Paper end
             } while (!this.playerIsCloseEnoughForSpawning(entityplayer, chunkcoordintpair, blockRange)); // Spigot
 
             return true;
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index b1fd6118132ba38f60d2a2b15c09231fa29be8fa..0f38bdf2c9a29f2111c27138b8d997c230633bb8 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -718,6 +718,15 @@ public class ServerChunkCache extends ChunkSource {
             boolean flag2 = this.level.getGameRules().getBoolean(GameRules.RULE_DOMOBSPAWNING) && !this.level.players().isEmpty(); // CraftBukkit
 
             Collections.shuffle(list);
+            // Paper start - call player naturally spawn event
+            int chunkRange = level.spigotConfig.mobSpawnRange;
+            chunkRange = (chunkRange > level.spigotConfig.viewDistance) ? (byte) level.spigotConfig.viewDistance : chunkRange;
+            chunkRange = Math.min(chunkRange, 8);
+            for (ServerPlayer entityPlayer : this.level.players()) {
+                entityPlayer.playerNaturallySpawnedEvent = new com.destroystokyo.paper.event.entity.PlayerNaturallySpawnCreaturesEvent(entityPlayer.getBukkitEntity(), (byte) chunkRange);
+                entityPlayer.playerNaturallySpawnedEvent.callEvent();
+            };
+            // Paper end
             Iterator iterator1 = list.iterator();
 
             while (iterator1.hasNext()) {
diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index 40efa19ffe9275748a62e0546c3fd42bbcb0883d..491dffdcbb065acf5861dc01b403d1a895c92baa 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -1,5 +1,6 @@
 package net.minecraft.server.level;
 
+import com.destroystokyo.paper.event.entity.PlayerNaturallySpawnCreaturesEvent;
 import com.google.common.collect.Lists;
 import com.google.common.net.InetAddresses;
 import com.mojang.authlib.GameProfile;
@@ -257,6 +258,7 @@ public class ServerPlayer extends Player {
     // CraftBukkit end
     public boolean isRealPlayer; // Paper
     public final com.destroystokyo.paper.util.misc.PooledLinkedHashSets.PooledObjectLinkedOpenHashSet<ServerPlayer> cachedSingleHashSet; // Paper
+    public PlayerNaturallySpawnCreaturesEvent playerNaturallySpawnedEvent; // Paper
 
     public ServerPlayer(MinecraftServer server, ServerLevel world, GameProfile profile, ClientInformation clientOptions) {
         super(world, world.getSharedSpawnPos(), world.getSharedSpawnAngle(), profile);