Fix sizeof struct within generic type instance

#1219

Source/Editor/CustomEditors/Dedicated/RagdollEditor.cs

@@ -167,7 +167,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
             Presenter.Undo?.AddAction(new MultiUndoAction(actions));
 
             // Build ragdoll
-            SceneGraph.Actors.AnimatedModelNode.BuildRagdoll(animatedModel, options, ragdoll);
+            AnimatedModelNode.BuildRagdoll(animatedModel, options, ragdoll);
         }
 
         private void OnRebuildBone(Button button)
@@ -191,7 +191,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
             }
 
             // Build ragdoll
-            SceneGraph.Actors.AnimatedModelNode.BuildRagdoll(animatedModel, new AnimatedModelNode.RebuildOptions(), ragdoll, name);
+            AnimatedModelNode.BuildRagdoll(animatedModel, new AnimatedModelNode.RebuildOptions(), ragdoll, name);
         }
 
         private void OnRemoveBone(Button button)

Source/Engine/Engine/NativeInterop.Managed.cs

@@ -50,13 +50,13 @@ namespace FlaxEngine.Interop
         /// <remarks>The resources must be released by calling FreePooled() instead of Free()-method.</remarks>
         public static ManagedArray WrapPooledArray(Array arr, Type arrayType)
         {
-            ManagedArray managedArray = ManagedArrayPool.Get(arr.Length * Marshal.SizeOf(arr.GetType().GetElementType()));
+            ManagedArray managedArray = ManagedArrayPool.Get(arr.Length * NativeInterop.GetTypeSize(arr.GetType().GetElementType()));
             managedArray.WrapArray(arr, arrayType);
             return managedArray;
         }
 
         internal static ManagedArray AllocateNewArray(int length, Type arrayType, Type elementType)
-            => new ManagedArray((IntPtr)NativeInterop.NativeAlloc(length, Marshal.SizeOf(elementType)), length, arrayType, elementType);
+            => new ManagedArray((IntPtr)NativeInterop.NativeAlloc(length, NativeInterop.GetTypeSize(elementType)), length, arrayType, elementType);
 
         internal static ManagedArray AllocateNewArray(IntPtr ptr, int length, Type arrayType, Type elementType)
             => new ManagedArray(ptr, length, arrayType, elementType);
@@ -86,7 +86,7 @@ namespace FlaxEngine.Interop
             _length = arr.Length;
             _arrayType = arrayType;
             _elementType = arr.GetType().GetElementType();
-            _elementSize = Marshal.SizeOf(_elementType);
+            _elementSize = NativeInterop.GetTypeSize(_elementType);
         }
 
         internal void Allocate<T>(int length) where T : unmanaged
@@ -117,7 +117,7 @@ namespace FlaxEngine.Interop
             _length = length;
             _arrayType = arrayType;
             _elementType = elementType;
-            _elementSize = Marshal.SizeOf(elementType);
+            _elementSize = NativeInterop.GetTypeSize(_elementType);
         }
 
         ~ManagedArray()

Source/Engine/Engine/NativeInterop.Unmanaged.cs

@@ -885,6 +885,7 @@ namespace FlaxEngine.Interop
                 handle.Free();
             fieldHandleCacheCollectible.Clear();
 #endif
+            _typeSizeCache.Clear();
 
             foreach (var pair in classAttributesCacheCollectible)
                 pair.Value.Free();

Source/Engine/Engine/NativeInterop.cs

@@ -46,6 +46,7 @@ namespace FlaxEngine.Interop
 #endif
         private static Dictionary<object, ManagedHandle> classAttributesCacheCollectible = new();
         private static Dictionary<Assembly, ManagedHandle> assemblyHandles = new();
+        private static Dictionary<Type, int> _typeSizeCache = new();
 
         private static Dictionary<string, IntPtr> loadedNativeLibraries = new();
         internal static Dictionary<string, string> nativeLibraryPaths = new();
@@ -584,7 +585,7 @@ namespace FlaxEngine.Interop
                     else if (fieldType.IsClass || fieldType.IsPointer)
                         fieldAlignment = IntPtr.Size;
                     else
-                        fieldAlignment = Marshal.SizeOf(fieldType);
+                        fieldAlignment = GetTypeSize(fieldType);
                 }
 
                 internal static void ToManagedField(FieldInfo field, ref T fieldOwner, IntPtr fieldPtr, out int fieldOffset)
@@ -1088,6 +1089,26 @@ namespace FlaxEngine.Interop
             return handle;
         }
 
+        internal static int GetTypeSize(Type type)
+        {
+            if (!_typeSizeCache.TryGetValue(type, out var size))
+            {
+                try
+                {
+                    size = Marshal.SizeOf(type);
+                }
+                catch
+                {
+                    // Workaround the issue where structure defined within generic type instance (eg. MyType<int>.MyStruct) fails to get size
+                    // https://github.com/dotnet/runtime/issues/46426
+                    var obj = Activator.CreateInstance(type);
+                    size = Marshal.SizeOf(obj);
+                }
+                _typeSizeCache.Add(type, size);
+            }
+            return size;
+        }
+
         private static class DelegateHelpers
         {
 #if USE_AOT

Source/Engine/Level/Spline.cs

@@ -23,8 +23,8 @@ namespace FlaxEngine
                 if (_keyframes == null || _keyframes.Length != count)
                     _keyframes = new BezierCurve<Transform>.Keyframe[count];
 #if !BUILD_RELEASE
-                if (Marshal.SizeOf(typeof(BezierCurve<Transform>.Keyframe)) != Transform.SizeInBytes * 3 + sizeof(float))
-                    throw new Exception("Invalid size of BezierCurve keyframe " + Marshal.SizeOf(typeof(BezierCurve<Transform>.Keyframe)) + " bytes.");
+                if (System.Runtime.CompilerServices.Unsafe.SizeOf<BezierCurve<Transform>.Keyframe>() != Transform.SizeInBytes * 3 + sizeof(float))
+                    throw new Exception("Invalid size of BezierCurve keyframe " + System.Runtime.CompilerServices.Unsafe.SizeOf<BezierCurve<Transform>.Keyframe>() + " bytes.");
 #endif
                 Internal_GetKeyframes(__unmanagedPtr, _keyframes);
                 return _keyframes;