Remove unnecessary thread-safety code from entity spawning

Eliminated redundant locks and related comments in EntitySpawner and Entity classes, simplifying the spawn and remove queue handling. Also removed outdated comments in GameScreen regarding thread safety. These changes assume entity spawning and removal are no longer performed from multiple threads, improving code clarity and maintainability.

Barotrauma/BarotraumaShared/SharedSource/Map/Entity.cs

@@ -147,7 +147,6 @@ namespace Barotrauma
                 CreationStackTrace += $"{fileName}@{fileLineNumber}; ";
             }
 #endif
-            #warning TODO: consider removing this mutex, entity creation probably shouldn't be multithreaded
             lock (creationCounterMutex)
             {
                 CreationIndex = creationCounter;

Barotrauma/BarotraumaShared/SharedSource/Networking/EntitySpawner.cs

@@ -5,7 +5,6 @@ using Microsoft.Xna.Framework;
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Threading;
 
 namespace Barotrauma
 {
@@ -206,7 +205,6 @@ namespace Barotrauma
         }
 
         private readonly Queue<Either<IEntitySpawnInfo, Entity>> spawnOrRemoveQueue;
-        private readonly object spawnOrRemoveQueueLock = new object();
 
         public abstract class SpawnOrRemove : NetEntityEvent.IData
         {
@@ -284,11 +282,8 @@ namespace Barotrauma
                 GameAnalyticsManager.AddErrorEventOnce("EntitySpawner.AddToSpawnQueue1:ItemPrefabNull", GameAnalyticsManager.ErrorSeverity.Error, errorMsg);
                 return;
             }
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(new ItemSpawnInfo(itemPrefab, worldPosition, onSpawned, condition, quality));
         }
-        }
 
         public void AddItemToSpawnQueue(ItemPrefab itemPrefab, Vector2 position, Submarine sub, float? condition = null, int? quality = null, Action<Item> onSpawned = null)
         {
@@ -300,11 +295,8 @@ namespace Barotrauma
                 GameAnalyticsManager.AddErrorEventOnce("EntitySpawner.AddToSpawnQueue2:ItemPrefabNull", GameAnalyticsManager.ErrorSeverity.Error, errorMsg);
                 return;
             }
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(new ItemSpawnInfo(itemPrefab, position, sub, onSpawned, condition, quality));
         }
-        }
 
         public void AddItemToSpawnQueue(ItemPrefab itemPrefab, Inventory inventory, float? condition = null, int? quality = null, Action<Item> onSpawned = null, bool spawnIfInventoryFull = true, bool ignoreLimbSlots = false, InvSlotType slot = InvSlotType.None)
         {
@@ -316,8 +308,6 @@ namespace Barotrauma
                 GameAnalyticsManager.AddErrorEventOnce("EntitySpawner.AddToSpawnQueue3:ItemPrefabNull", GameAnalyticsManager.ErrorSeverity.Error, errorMsg);
                 return;
             }
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(new ItemSpawnInfo(itemPrefab, inventory, onSpawned, condition, quality) 
             { 
                 SpawnIfInventoryFull = spawnIfInventoryFull, 
@@ -325,7 +315,6 @@ namespace Barotrauma
                 Slot = slot
             });
         }
-        }
 
         public void AddCharacterToSpawnQueue(Identifier speciesName, Vector2 worldPosition, Action<Character> onSpawn = null)
         {
@@ -337,11 +326,8 @@ namespace Barotrauma
                 GameAnalyticsManager.AddErrorEventOnce("EntitySpawner.AddToSpawnQueue4:SpeciesNameNullOrEmpty", GameAnalyticsManager.ErrorSeverity.Error, errorMsg);
                 return;
             }
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(new CharacterSpawnInfo(speciesName, worldPosition, onSpawn));
         }
-        }
 
         public void AddCharacterToSpawnQueue(Identifier speciesName, Vector2 position, Submarine sub, Action<Character> onSpawn = null)
         {
@@ -353,11 +339,8 @@ namespace Barotrauma
                 GameAnalyticsManager.AddErrorEventOnce("EntitySpawner.AddToSpawnQueue5:SpeciesNameNullOrEmpty", GameAnalyticsManager.ErrorSeverity.Error, errorMsg);
                 return;
             }
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(new CharacterSpawnInfo(speciesName, position, sub, onSpawn));
         }
-        }
 
         public void AddCharacterToSpawnQueue(Identifier speciesName, Vector2 worldPosition, CharacterInfo characterInfo, Action<Character> onSpawn = null)
         {
@@ -369,11 +352,8 @@ namespace Barotrauma
                 GameAnalyticsManager.AddErrorEventOnce("EntitySpawner.AddToSpawnQueue4:SpeciesNameNullOrEmpty", GameAnalyticsManager.ErrorSeverity.Error, errorMsg);
                 return;
             }
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(new CharacterSpawnInfo(speciesName, worldPosition, characterInfo, onSpawn));
         }
-        }
 
         public void AddEntityToRemoveQueue(Entity entity)
         {
@@ -395,21 +375,15 @@ namespace Barotrauma
 #endif
             }
 
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(entity);
         }
-        }
 
         public void AddItemToRemoveQueue(Item item)
         {
             if (GameMain.NetworkMember != null && GameMain.NetworkMember.IsClient) { return; }
             if (IsInRemoveQueue(item) || item.Removed) { return; }
 
-            lock (spawnOrRemoveQueueLock)
-            {
             spawnOrRemoveQueue.Enqueue(item);
-            }
             item.IsInRemoveQueue = true;
 
             foreach (var containedItem in item.ContainedItems)
@@ -425,8 +399,6 @@ namespace Barotrauma
         /// Are there any entities in the spawn queue that match the given predicate
         /// </summary>
         public bool IsInSpawnQueue(Predicate<IEntitySpawnInfo> predicate)
-        {
-            lock (spawnOrRemoveQueueLock)
         {
             foreach (var spawnOrRemove in spawnOrRemoveQueue)
             {
@@ -434,14 +406,11 @@ namespace Barotrauma
             }
             return false;
         }
-        }
 
         /// <summary>
         /// How many entities in the spawn queue match the given predicate
         /// </summary>
         public int CountSpawnQueue(Predicate<IEntitySpawnInfo> predicate)
-        {
-            lock (spawnOrRemoveQueueLock)
         {
             int count = 0;
             foreach (var spawnOrRemove in spawnOrRemoveQueue)
@@ -450,11 +419,8 @@ namespace Barotrauma
             }
             return count;
         }
-        }
 
         public bool IsInRemoveQueue(Entity entity)
-        {
-            lock (spawnOrRemoveQueueLock)
         {
             foreach (var spawnOrRemove in spawnOrRemoveQueue)
             {
@@ -462,19 +428,13 @@ namespace Barotrauma
             }
             return false;
         }
-        }
 
         public void Update(bool createNetworkEvents = true)
         {
             if (GameMain.NetworkMember is { IsClient: true }) { return; }
-            while (true)
+            while (spawnOrRemoveQueue.Count > 0)
             {
-                Either<IEntitySpawnInfo, Entity> spawnOrRemove;
+                if (!spawnOrRemoveQueue.TryDequeue(out var spawnOrRemove)) { break; }
-                lock (spawnOrRemoveQueueLock)
-                {
-                    if (spawnOrRemoveQueue.Count == 0) { break; }
-                    spawnOrRemove = spawnOrRemoveQueue.Dequeue();
-                }
                 if (spawnOrRemove.TryGet(out Entity entityToRemove))
                 {
                     if (entityToRemove is Item item)
@@ -504,11 +464,8 @@ namespace Barotrauma
         partial void CreateNetworkEventProjSpecific(SpawnOrRemove spawnOrRemove);
 
         public void Reset()
-        {
-            lock (spawnOrRemoveQueueLock)
         {
             spawnOrRemoveQueue.Clear();
-            }
 #if CLIENT
             receivedEvents.Clear();
 #endif

Barotrauma/BarotraumaShared/SharedSource/Screens/GameScreen.cs

@@ -286,7 +286,6 @@ namespace Barotrauma
                 }
             );
             
-            // Process any physics operations queued during parallel updates
             PhysicsBodyQueue.ProcessPendingOperations();
 #endif
 
@@ -311,7 +310,6 @@ namespace Barotrauma
 
             MapEntity.UpdateAll((float)deltaTime, Camera.Instance, parallelOptions);
 
-            //StatusEffect.UpdateAll is not thread-safe and must be executed on the main thread
             StatusEffect.UpdateAll((float)deltaTime);
 
 #endif