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 3b6f35b695117bd2b0c71b994efc55fa1084eddc..97d5437df10a6d0124e944404e88650547b7d8a8 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -964,12 +964,23 @@ 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.a(i).noneMatch((entityplayer) -> {
-            return !entityplayer.isSpectator() && a(chunkcoordintpair, (Entity) entityplayer) < blockRange; // Spigot
+            // Paper start -
+            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));
+            }
+
+            return (!entityplayer.isSpectator() && a(chunkcoordintpair, (Entity) entityplayer) < blockRange); // Spigot
+            // Paper end
         });
     }
 
diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
index d0b0fdaf5451bcc7f7ac7dab28aa59ef77e6dd97..a7122a0411f4a8656efd4facde3403c8093bc8a6 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -612,6 +612,15 @@ public class ServerChunkCache extends ChunkSource {
             this.level.getProfiler().pop();
             //List<PlayerChunk> list = Lists.newArrayList(this.playerChunkMap.f()); // Paper
             //Collections.shuffle(list); // Paper
+            //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
             this.chunkMap.getChunks().forEach((playerchunk) -> { // Paper - no... just no...
                 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 4ff66138fa43cf932b95d6d3dc050a9cd7b28ad4..0fa977a31cf945b74f3a046b6be302b10f494ad1 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;
@@ -225,6 +226,7 @@ public class ServerPlayer extends Player implements ContainerListener {
     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