Add JsonAssetReference type for scripting

Source/Editor/CustomEditors/Editors/AssetRefEditor.cs

@@ -51,10 +51,13 @@ namespace FlaxEditor.CustomEditors.Editors
                 return;
             Picker = layout.Custom<AssetPicker>().CustomControl;
 
-            _valueType = Values.Type.Type != typeof(object) || Values[0] == null ? Values.Type : TypeUtils.GetObjectType(Values[0]);
+            var value = Values[0];
+            _valueType = Values.Type.Type != typeof(object) || value == null ? Values.Type : TypeUtils.GetObjectType(value);
             var assetType = _valueType;
             if (assetType == typeof(string))
                 assetType = new ScriptType(typeof(Asset));
+            else if (_valueType.Type != null && _valueType.Type.Name == typeof(JsonAssetReference<>).Name)
+                assetType = new ScriptType(_valueType.Type.GenericTypeArguments[0]);
 
             float height = 48;
             var attributes = Values.GetAttributes();
@@ -102,6 +105,12 @@ namespace FlaxEditor.CustomEditors.Editors
                 SetValue(new SceneReference(Picker.Validator.SelectedID));
             else if (_valueType.Type == typeof(string))
                 SetValue(Picker.Validator.SelectedPath);
+            else if (_valueType.Type.Name == typeof(JsonAssetReference<>).Name)
+            {
+                var value = Values[0];
+                value.GetType().GetField("Asset").SetValue(value, Picker.Validator.SelectedAsset as JsonAsset);
+                SetValue(value);
+            }
             else
                 SetValue(Picker.Validator.SelectedAsset);
         }
@@ -114,16 +123,19 @@ namespace FlaxEditor.CustomEditors.Editors
             if (!HasDifferentValues)
             {
                 _isRefreshing = true;
-                if (Values[0] is AssetItem assetItem)
+                var value = Values[0];
+                if (value is AssetItem assetItem)
                     Picker.Validator.SelectedItem = assetItem;
-                else if (Values[0] is Guid guid)
+                else if (value is Guid guid)
                     Picker.Validator.SelectedID = guid;
-                else if (Values[0] is SceneReference sceneAsset)
+                else if (value is SceneReference sceneAsset)
                     Picker.Validator.SelectedItem = Editor.Instance.ContentDatabase.FindAsset(sceneAsset.ID);
-                else if (Values[0] is string path)
+                else if (value is string path)
                     Picker.Validator.SelectedPath = path;
+                else if (value != null && value.GetType().Name == typeof(JsonAssetReference<>).Name)
+                    Picker.Validator.SelectedAsset = value.GetType().GetField("Asset").GetValue(value) as JsonAsset;
                 else
-                    Picker.Validator.SelectedAsset = Values[0] as Asset;
+                    Picker.Validator.SelectedAsset = value as Asset;
                 _isRefreshing = false;
             }
         }

Source/Engine/Content/JsonAssetReference.cs

@@ -0,0 +1,83 @@
+// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.
+
+using System;
+
+namespace FlaxEngine
+{
+    /// <summary>
+    /// Json asset reference utility. References resource with a typed data type.
+    /// </summary>
+    /// <typeparam name="T">Type of the asset instance type.</typeparam>
+#if FLAX_EDITOR
+    [CustomEditor(typeof(FlaxEditor.CustomEditors.Editors.AssetRefEditor))]
+#endif
+    public struct JsonAssetReference<T>
+    {
+        /// <summary>
+        /// Gets or sets the referenced asset.
+        /// </summary>
+        public JsonAsset Asset;
+
+        /// <summary>
+        /// Gets the instance of the Json Asset. Null if unset.
+        /// </summary>
+        /// <returns>instance of the Json Asset or null if unset.</returns>
+        public T Get()
+        {
+            return (T)Asset?.Instance;
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JsonAssetReference{T}"/> structure.
+        /// </summary>
+        /// <param name="asset">The Json Asset.</param>
+        public JsonAssetReference(JsonAsset asset)
+        {
+            Asset = asset;
+        }
+
+        /// <summary>
+        /// Implicit cast operator.
+        /// </summary>
+        public static implicit operator JsonAsset(JsonAssetReference<T> value)
+        {
+            return value.Asset;
+        }
+
+        /// <summary>
+        /// Implicit cast operator.
+        /// </summary>
+        public static implicit operator IntPtr(JsonAssetReference<T> value)
+        {
+            return Object.GetUnmanagedPtr(value.Asset);
+        }
+
+        /// <summary>
+        /// Implicit cast operator.
+        /// </summary>
+        public static implicit operator JsonAssetReference<T>(JsonAsset value)
+        {
+            return new JsonAssetReference<T>(value);
+        }
+
+        /// <summary>
+        /// Implicit cast operator.
+        /// </summary>
+        public static implicit operator JsonAssetReference<T>(IntPtr valuePtr)
+        {
+            return new JsonAssetReference<T>(Object.FromUnmanagedPtr(valuePtr) as JsonAsset);
+        }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return Asset?.ToString();
+        }
+
+        /// <inheritdoc />
+        public override int GetHashCode()
+        {
+            return Asset?.GetHashCode() ?? 0;
+        }
+    }
+}

Source/Engine/Content/JsonAssetReference.h

@@ -0,0 +1,25 @@
+// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#include "Engine/Content/JsonAsset.h"
+#include "Engine/Content/AssetReference.h"
+
+/// <summary>
+/// Json asset reference utility. References resource with a typed data type.
+/// </summary>
+/// <typeparam name="T">Type of the asset instance type.</typeparam>
+template<typename T>
+API_STRUCT(NoDefault, Template, MarshalAs=JsonAsset*) struct JsonAssetReference : AssetReference<JsonAsset>
+{
+    JsonAssetReference& operator=(JsonAsset* asset) noexcept
+    {
+        OnSet(asset);
+        return *this;
+    }
+
+    operator JsonAsset*() const
+    {
+        return Get();
+    }
+};