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 5ce8ac377b0d2b05dd90baa67f420945cc419609..919a489a5c7b338659c62ae67fc0a6ceee9dcdf9 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -975,11 +975,21 @@ 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
         // Spigot end
         long i = chunkcoordintpair.toLong();
 
         return !this.distanceManager.hasPlayersNearby(i) ? true : this.playerMap.getPlayers(i).noneMatch((entityplayer) -> {
+            // Paper start - add PlayerNaturallySpawnCreaturesEvent
+            com.destroystokyo.paper.event.entity.PlayerNaturallySpawnCreaturesEvent event;
+            double 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
             return !entityplayer.isSpectator() && ChunkMap.euclideanDistanceSquared(chunkcoordintpair, (Entity) entityplayer) < blockRange; // Spigot
         });
     }
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index c5bffd1b40ca9ae3c973044c1ad4947ba2c285ae..918555ba0af8a779ad55c7cf73f615eb804d00d9 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -632,6 +632,15 @@ public class ServerChunkCache extends ChunkSource {
             List<ChunkHolder> list = Lists.newArrayList(this.chunkMap.getChunks());
 
             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
             this.level.timings.chunkTicks.startTiming(); // Paper
             list.forEach((playerchunk) -> {
                 Optional<LevelChunk> optional = ((Either) playerchunk.getTickingChunkFuture().getNow(ChunkHolder.UNLOADED_LEVEL_CHUNK)).left();
diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index 823fc38b5bbf5eac2d2e7cc48c4b0557d252f960..fb42d7e3a1a23c02e8fd2cc04e6986ead581018c 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.mojang.authlib.GameProfile;
 import com.mojang.datafixers.util.Either;
@@ -233,6 +234,7 @@ public class ServerPlayer extends Player {
     public boolean sentListPacket = false;
     public Integer clientViewDistance;
     // CraftBukkit end
+    public PlayerNaturallySpawnCreaturesEvent playerNaturallySpawnedEvent; // Paper
 
     public final com.destroystokyo.paper.util.misc.PooledLinkedHashSets.PooledObjectLinkedOpenHashSet<ServerPlayer> cachedSingleHashSet; // Paper