Add SyncVar/Field change events

- Implemented `ISyncFieldChanged<T>` interface for syncable fields to handle value changes.
- Added `ValueChanged` event in relevant classes to notify when values change.
- Updated methods to include field names in processing for better tracking.
- Introduced a callback registry to manage and invoke user-defined callbacks on type value changes.

Author: ltwlf

LiteEntitySystem/ClientEntityManager.cs

@@ -511,11 +511,11 @@ private unsafe void GoToNextState()
                         if (field.FieldType == FieldType.SyncableSyncVar)
                         {
                             var syncableField = RefMagic.RefFieldValue<SyncableField>(entity, field.Offset);
-                            field.TypeProcessor.SetFrom(syncableField, field.SyncableSyncVarOffset, predictedData + field.PredictedOffset);
+                            field.TypeProcessor.SetFrom(syncableField, field.SyncableSyncVarOffset, predictedData + field.PredictedOffset, field.Name);
                         }
                         else
                         {
-                            field.TypeProcessor.SetFrom(entity, field.Offset, predictedData + field.PredictedOffset);
+                            field.TypeProcessor.SetFrom(entity, field.Offset, predictedData + field.PredictedOffset, field.Name);
                         }
                     }
                 }
@@ -649,7 +649,7 @@ protected override unsafe void OnLogicTick()
                         for(int i = 0; i < classData.InterpolatedCount; i++)
                         {
                             var field = classData.Fields[i];
-                            field.TypeProcessor.SetFrom(entity, field.Offset, currentDataPtr + field.FixedOffset);
+                            field.TypeProcessor.SetFrom(entity, field.Offset, currentDataPtr + field.FixedOffset, field.Name);
                         }
 
                         //update
@@ -1002,7 +1002,7 @@ private unsafe bool ReadEntityState(byte* rawData, bool fistSync)
                         if (field.FieldType == FieldType.SyncableSyncVar)
                         {
                             var syncableField = RefMagic.RefFieldValue<SyncableField>(entity, field.Offset);
-                            field.TypeProcessor.SetFrom(syncableField, field.SyncableSyncVarOffset, readDataPtr);
+                            field.TypeProcessor.SetFrom(syncableField, field.SyncableSyncVarOffset, readDataPtr, field.Name);
                         }
                         else
                         {
@@ -1023,7 +1023,7 @@ private unsafe bool ReadEntityState(byte* rawData, bool fistSync)
                             }
                             else
                             {
-                                field.TypeProcessor.SetFrom(entity, field.Offset, readDataPtr);
+                                field.TypeProcessor.SetFrom(entity, field.Offset, readDataPtr, field.Name);
                             }
                         }
                         //Logger.Log($"E {entity.Id} Field updated: {field.Name}");

LiteEntitySystem/Extensions/SyncNetSerializable.cs

@@ -1,17 +1,20 @@
 using System;
+using System.Collections.Generic;
 using K4os.Compression.LZ4;
 using LiteNetLib.Utils;
 
 namespace LiteEntitySystem.Extensions
 {
-    public class SyncNetSerializable<T> : SyncableField where T : INetSerializable
+    public class SyncNetSerializable<T> : SyncableField, ISyncFieldChanged<T> where T : INetSerializable
     {
         private static readonly NetDataWriter WriterCache = new();
         private static readonly NetDataReader ReaderCache = new();
         private static byte[] CompressionBuffer;
-        
+
         private T _value;
 
+        public event Action<T, T> ValueChanged;
+
         public T Value
         {
             get => _value;
@@ -45,8 +48,9 @@ protected internal override void OnSyncRequested()
                 Logger.LogError("Too much sync data!");
                 return;
             }
+
             int bufSize = LZ4Codec.MaximumOutputSize(WriterCache.Length) + 2;
-            if(CompressionBuffer == null || CompressionBuffer.Length < bufSize)
+            if (CompressionBuffer == null || CompressionBuffer.Length < bufSize)
                 CompressionBuffer = new byte[bufSize];
             FastBitConverter.GetBytes(CompressionBuffer, 0, (ushort)WriterCache.Length);
             int encodedLength = LZ4Codec.Encode(
@@ -55,20 +59,36 @@ protected internal override void OnSyncRequested()
                 WriterCache.Length,
                 CompressionBuffer,
                 2,
-                CompressionBuffer.Length-2,
+                CompressionBuffer.Length - 2,
                 LZ4Level.L00_FAST);
-            ExecuteRPC(_initAction, new ReadOnlySpan<byte>(CompressionBuffer, 0, encodedLength+2));
+            ExecuteRPC(_initAction, new ReadOnlySpan<byte>(CompressionBuffer, 0, encodedLength + 2));
         }
 
         private void Init(ReadOnlySpan<byte> data)
         {
+            // Read uncompressed size
             ushort origSize = BitConverter.ToUInt16(data);
+
             if (CompressionBuffer == null || CompressionBuffer.Length < origSize)
                 CompressionBuffer = new byte[origSize];
             LZ4Codec.Decode(data[2..], new Span<byte>(CompressionBuffer));
             ReaderCache.SetSource(CompressionBuffer, 0, origSize);
-            _value ??= _constructor();
-            _value.Deserialize(ReaderCache);
+
+            // Capture the old reference
+            T oldValue = _value;
+
+            // Always create a fresh instance for deserialization
+            T newValue = _constructor();
+            newValue.Deserialize(ReaderCache);
+
+            // Update _value
+            _value = newValue;
+
+            // Compare old and new. If changed, raise event.
+            if (oldValue == null || !EqualityComparer<T>.Default.Equals(oldValue, _value))
+            {
+                ValueChanged?.Invoke(oldValue, newValue);
+            }
         }
 
         public static implicit operator T(SyncNetSerializable<T> field)

LiteEntitySystem/Extensions/SyncString.cs

@@ -1,9 +1,11 @@
 using System;
+using System.Runtime.CompilerServices;
 using System.Text;
+using LiteEntitySystem.Internal;
 
 namespace LiteEntitySystem.Extensions
 {
-    public class SyncString : SyncableField
+    public class SyncString : SyncableField, ISyncFieldChanged<string>
     {
         private static readonly UTF8Encoding Encoding = new(false, true);
         private byte[] _stringData;
@@ -12,6 +14,7 @@ public class SyncString : SyncableField
 
         private static RemoteCallSpan<byte> _setStringClientCall;
 
+        public event Action<string, string> ValueChanged;
         public string Value
         {
             get => _string;
@@ -43,7 +46,9 @@ public static implicit operator string(SyncString s)
 
         private void SetNewString(ReadOnlySpan<byte> data)
         {
-            _string = Encoding.GetString(data);
+            var newString = Encoding.GetString(data);
+            ValueChanged?.Invoke(_string, newString);
+            _string = newString;
         }
 
         protected internal override void OnSyncRequested()