From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: kickash32 <kickash32@gmail.com>
Date: Mon, 5 Apr 2021 01:42:35 -0400
Subject: [PATCH] Improve cancelling PreCreatureSpawnEvent with per player mob
 spawns


diff --git a/net/minecraft/server/level/ChunkMap.java b/net/minecraft/server/level/ChunkMap.java
index 6c5b2eb411fb60babbb0c74d5c075696ef70b38d..cf439285e4ba9babda228c36aa81dfc49db2c22a 100644
--- a/net/minecraft/server/level/ChunkMap.java
+++ b/net/minecraft/server/level/ChunkMap.java
@@ -256,8 +256,25 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
         }
     }
 
+    // Paper start - per player mob count backoff
+    public void updateFailurePlayerMobTypeMap(int chunkX, int chunkZ, net.minecraft.world.entity.MobCategory mobCategory) {
+        if (!this.level.paperConfig().entities.spawning.perPlayerMobSpawns) {
+            return;
+        }
+        int idx = mobCategory.ordinal();
+        final ca.spottedleaf.moonrise.common.list.ReferenceList<ServerPlayer> inRange =
+            this.level.moonrise$getNearbyPlayers().getPlayersByChunk(chunkX, chunkZ, ca.spottedleaf.moonrise.common.misc.NearbyPlayers.NearbyMapType.TICK_VIEW_DISTANCE);
+        if (inRange == null) {
+            return;
+        }
+        final ServerPlayer[] backingSet = inRange.getRawDataUnchecked();
+        for (int i = 0, len = inRange.size(); i < len; i++) {
+            ++(backingSet[i].mobBackoffCounts[idx]);
+        }
+    }
+    // Paper end - per player mob count backoff
     public int getMobCountNear(final ServerPlayer player, final net.minecraft.world.entity.MobCategory mobCategory) {
-        return player.mobCounts[mobCategory.ordinal()];
+        return player.mobCounts[mobCategory.ordinal()] + player.mobBackoffCounts[mobCategory.ordinal()]; // Paper - per player mob count backoff
      }
     // Paper end - Optional per player mob spawns
 
diff --git a/net/minecraft/server/level/ServerChunkCache.java b/net/minecraft/server/level/ServerChunkCache.java
index 078f208e104a652ce48458150389d19ede6808ef..aa141c00a41d49daee8e4ab7be70ce4e4767b105 100644
--- a/net/minecraft/server/level/ServerChunkCache.java
+++ b/net/minecraft/server/level/ServerChunkCache.java
@@ -479,7 +479,17 @@ public class ServerChunkCache extends ChunkSource {
         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) {
-                Arrays.fill(player.mobCounts, 0);
+                // Paper start - per player mob spawning backoff
+                for (int ii = 0; ii < ServerPlayer.MOBCATEGORY_TOTAL_ENUMS; ii++) {
+                    player.mobCounts[ii] = 0;
+
+                    int newBackoff = player.mobBackoffCounts[ii] - 1; // TODO make configurable bleed // TODO use nonlinear algorithm?
+                    if (newBackoff < 0) {
+                        newBackoff = 0;
+                    }
+                    player.mobBackoffCounts[ii] = newBackoff;
+                }
+                // Paper end - per player mob spawning backoff
             }
             spawnState = NaturalSpawner.createState(naturalSpawnChunkCount, this.level.getAllEntities(), this::getFullChunk, null, true);
         } else {
diff --git a/net/minecraft/server/level/ServerPlayer.java b/net/minecraft/server/level/ServerPlayer.java
index dab58457ed02d3f8153c07de101262b1a0182d71..2d20f42fbcfb67845323d994843d7b977aa867e0 100644
--- a/net/minecraft/server/level/ServerPlayer.java
+++ b/net/minecraft/server/level/ServerPlayer.java
@@ -372,6 +372,7 @@ public class ServerPlayer extends Player {
     public static final int MOBCATEGORY_TOTAL_ENUMS = net.minecraft.world.entity.MobCategory.values().length;
     public final int[] mobCounts = new int[MOBCATEGORY_TOTAL_ENUMS];
     // Paper end - Optional per player mob spawns
+    public final int[] mobBackoffCounts = new int[MOBCATEGORY_TOTAL_ENUMS]; // Paper - per player mob count backoff
     // CraftBukkit start
     public org.bukkit.craftbukkit.entity.CraftPlayer.TransferCookieConnection transferCookieConnection;
     public String displayName;
diff --git a/net/minecraft/world/level/NaturalSpawner.java b/net/minecraft/world/level/NaturalSpawner.java
index 5e82a8fdaec5a6750040ebb687aa35bba4dcc2ba..23f7fb22906e49babc7784f4b3d1f8ea8e187b1d 100644
--- a/net/minecraft/world/level/NaturalSpawner.java
+++ b/net/minecraft/world/level/NaturalSpawner.java
@@ -285,6 +285,11 @@ public final class NaturalSpawner {
 
                             // Paper start - PreCreatureSpawnEvent
                             PreSpawnStatus doSpawning = isValidSpawnPostitionForType(level, category, structureManager, generator, spawnerData, mutableBlockPos, d2);
+                            // Paper start - per player mob count backoff
+                            if (doSpawning == PreSpawnStatus.ABORT || doSpawning == PreSpawnStatus.CANCELLED) {
+                                level.getChunkSource().chunkMap.updateFailurePlayerMobTypeMap(mutableBlockPos.getX() >> 4, mutableBlockPos.getZ() >> 4, category);
+                            }
+                            // Paper end - per player mob count backoff
                             if (doSpawning == PreSpawnStatus.ABORT) {
                                 return;
                             }