From 60a478db9cdc5c6339e85be4baf3e984d11c4b88 Mon Sep 17 00:00:00 2001
From: md_5 <md_5@live.com.au>
Date: Fri, 21 Jun 2013 17:29:54 +1000
Subject: [PATCH] Fix Mob Spawning Relative to View Distance

Changes the mob spawning algorithm to properly account for view distance and the range around players.

Needs better documentation.

diff --git a/src/main/java/net/minecraft/server/level/ChunkProviderServer.java b/src/main/java/net/minecraft/server/level/ChunkProviderServer.java
index e990a1b17..06cf1b8a5 100644
--- a/src/main/java/net/minecraft/server/level/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/level/ChunkProviderServer.java
@@ -439,7 +439,7 @@ public class ChunkProviderServer extends IChunkProvider {
 
                     if (this.level.isNaturalSpawningAllowed(chunkcoordintpair) && this.chunkMap.anyPlayerCloseEnoughForSpawning(chunkcoordintpair)) {
                         chunk1.incrementInhabitedTime(j);
-                        if (flag && (this.spawnEnemies || this.spawnFriendlies) && this.level.getWorldBorder().isWithinBounds(chunkcoordintpair)) {
+                        if (flag && (this.spawnEnemies || this.spawnFriendlies) && this.level.getWorldBorder().isWithinBounds(chunkcoordintpair) && this.chunkMap.anyPlayerCloseEnoughForSpawning(chunkcoordintpair, true)) { // Spigot
                             SpawnerCreature.spawnForChunk(this.level, chunk1, spawnercreature_d, this.spawnFriendlies, this.spawnEnemies, flag1);
                         }
 
diff --git a/src/main/java/net/minecraft/server/level/PlayerChunkMap.java b/src/main/java/net/minecraft/server/level/PlayerChunkMap.java
index d2f717803..e0db2aa0d 100644
--- a/src/main/java/net/minecraft/server/level/PlayerChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/PlayerChunkMap.java
@@ -1107,6 +1107,17 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
     }
 
     boolean anyPlayerCloseEnoughForSpawning(ChunkCoordIntPair chunkcoordintpair) {
+        // Spigot start
+        return anyPlayerCloseEnoughForSpawning(chunkcoordintpair, false);
+    }
+
+    boolean anyPlayerCloseEnoughForSpawning(ChunkCoordIntPair chunkcoordintpair, boolean reducedRange) {
+        int chunkRange = level.spigotConfig.mobSpawnRange;
+        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;
+        // Spigot end
         if (!this.distanceManager.hasPlayersNearby(chunkcoordintpair.toLong())) {
             return false;
         } else {
@@ -1120,7 +1131,7 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
                 }
 
                 entityplayer = (EntityPlayer) iterator.next();
-            } while (!this.playerIsCloseEnoughForSpawning(entityplayer, chunkcoordintpair));
+            } while (!this.playerIsCloseEnoughForSpawning(entityplayer, chunkcoordintpair, blockRange)); // Spigot
 
             return true;
         }
@@ -1138,7 +1149,7 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
             while (iterator.hasNext()) {
                 EntityPlayer entityplayer = (EntityPlayer) iterator.next();
 
-                if (this.playerIsCloseEnoughForSpawning(entityplayer, chunkcoordintpair)) {
+                if (this.playerIsCloseEnoughForSpawning(entityplayer, chunkcoordintpair, 16384.0D)) { // Spigot
                     builder.add(entityplayer);
                 }
             }
@@ -1147,13 +1158,13 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
         }
     }
 
-    private boolean playerIsCloseEnoughForSpawning(EntityPlayer entityplayer, ChunkCoordIntPair chunkcoordintpair) {
+    private boolean playerIsCloseEnoughForSpawning(EntityPlayer entityplayer, ChunkCoordIntPair chunkcoordintpair, double range) { // Spigot
         if (entityplayer.isSpectator()) {
             return false;
         } else {
             double d0 = euclideanDistanceSquared(chunkcoordintpair, entityplayer);
 
-            return d0 < 16384.0D;
+            return d0 < range; // Spigot
         }
     }
 
diff --git a/src/main/java/org/spigotmc/SpigotWorldConfig.java b/src/main/java/org/spigotmc/SpigotWorldConfig.java
index acaf90301..0c0c29efe 100644
--- a/src/main/java/org/spigotmc/SpigotWorldConfig.java
+++ b/src/main/java/org/spigotmc/SpigotWorldConfig.java
@@ -180,4 +180,11 @@ public class SpigotWorldConfig
 
         log( "Simulation Distance: " + simulationDistance );
     }
+
+    public byte mobSpawnRange;
+    private void mobSpawnRange()
+    {
+        mobSpawnRange = (byte) getInt( "mob-spawn-range", 6 );
+        log( "Mob Spawn Range: " + mobSpawnRange );
+    }
 }
-- 
2.43.0