Paper/patches/server/1054-Improve-cancelling-PreCreatureSpawnEvent-with-per-pl.patch

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/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index 4896c3ba81ead769972fa9efdbe563d4006e4401..5b3a886c624b36557cbfaccdc3fb05a46a4ba36a 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -246,8 +246,25 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
             ++(backingSet[i].mobCounts[index]);
         }
     }
+    // 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
     }
     // 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 12f49deea35ecbaea08869332982c00af7cf99d9..3c711e1df57ac5b0f8795ebb12299d275792b1d4 100644
--- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
+++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
@@ -558,7 +558,17 @@ public class ServerChunkCache extends ChunkSource implements ca.spottedleaf.moon
         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
             }
             spawnercreature_d = NaturalSpawner.createState(naturalSpawnChunkCount, this.level.getAllEntities(), this::getFullChunk, null, true);
         } else {
diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index 8cc02ee9b1a710e35eb65a5a095681cc7dc542bb..4e4e5b7e8c387cf13cf5bc5e39d334c3222c9103 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -307,6 +307,7 @@ public class ServerPlayer extends net.minecraft.world.entity.player.Player imple
     public static final int MOBCATEGORY_TOTAL_ENUMS = net.minecraft.world.entity.MobCategory.values().length;
     public final int[] mobCounts = new int[MOBCATEGORY_TOTAL_ENUMS]; // Paper
     // 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 CraftPlayer.TransferCookieConnection transferCookieConnection;
diff --git a/src/main/java/net/minecraft/world/level/NaturalSpawner.java b/src/main/java/net/minecraft/world/level/NaturalSpawner.java
index 0beb5ab48c5405d9bc2ad8d0c430312f456d38c2..5297798c2be1ba85569c2b92ed221956bf75477a 100644
--- a/src/main/java/net/minecraft/world/level/NaturalSpawner.java
+++ b/src/main/java/net/minecraft/world/level/NaturalSpawner.java
@@ -299,6 +299,11 @@ public final class NaturalSpawner {
 
                                     // Paper start - PreCreatureSpawnEvent
                                     PreSpawnStatus doSpawning = isValidSpawnPostitionForType(world, group, structuremanager, chunkgenerator, biomesettingsmobs_c, blockposition_mutableblockposition, d2);
+                                    // Paper start - per player mob count backoff
+                                    if (doSpawning == PreSpawnStatus.ABORT || doSpawning == PreSpawnStatus.CANCELLED) {
+                                        world.getChunkSource().chunkMap.updateFailurePlayerMobTypeMap(blockposition_mutableblockposition.getX() >> 4, blockposition_mutableblockposition.getZ() >> 4, group);
+                                    }
+                                    // Paper end - per player mob count backoff
                                     if (doSpawning == PreSpawnStatus.ABORT) {
                                         return;
                                     }