Add support for editing JsonAsset data at runtime (eg. modify game settings on the fly)

Source/Engine/Content/JsonAsset.cpp

@@ -1,7 +1,6 @@
 // Copyright (c) 2012-2022 Wojciech Figat. All rights reserved.
 
 #include "JsonAsset.h"
-#include "Engine/Threading/Threading.h"
 #if USE_EDITOR
 #include "Engine/Platform/File.h"
 #include "Engine/Core/Types/DataContainer.h"
@@ -14,6 +13,7 @@
 #include "Cache/AssetsCache.h"
 #include "Engine/Core/Log.h"
 #include "Engine/Serialization/JsonTools.h"
+#include "Engine/Serialization/JsonWriters.h"
 #include "Engine/Content/Factories/JsonAssetFactory.h"
 #include "Engine/Core/Cache.h"
 #include "Engine/Debug/Exceptions/JsonParseException.h"
@@ -22,6 +22,7 @@
 #include "Engine/Scripting/ManagedCLR/MClass.h"
 #include "Engine/Scripting/ManagedCLR/MField.h"
 #include "Engine/Utilities/StringConverter.h"
+#include "Engine/Threading/Threading.h"
 
 JsonAssetBase::JsonAssetBase(const SpawnParams& params, const AssetInfo* info)
     : Asset(params, info)
@@ -45,9 +46,22 @@ String JsonAssetBase::GetData() const
     return String((const char*)buffer.GetString(), (int32)buffer.GetSize());
 }
 
+void JsonAssetBase::SetData(const StringView& value)
+{
+    if (!IsLoaded())
+        return;
+    PROFILE_CPU_NAMED("JsonAsset.SetData");
+    const StringAnsi dataJson(value);
+    ScopeLock lock(Locker);
+    const StringView dataTypeName = DataTypeName;
+    if (Init(dataTypeName, dataJson))
+    {
+        LOG(Error, "Failed to set Json asset data.");
+    }
+}
+
 bool JsonAssetBase::Init(const StringView& dataTypeName, const StringAnsiView& dataJson)
 {
-    CHECK_RETURN(IsVirtual(), true);
     unload(true);
     DataTypeName = dataTypeName;
     DataEngineBuild = FLAXENGINE_VERSION_BUILD;
@@ -63,6 +77,7 @@ bool JsonAssetBase::Init(const StringView& dataTypeName, const StringAnsiView& d
         return true;
     }
     Data = &Document;
+    _isVirtualDocument = true;
 
     // Load asset-specific data
     return loadAsset() != LoadResult::Ok;
@@ -137,7 +152,7 @@ void JsonAssetBase::GetReferences(Array<Guid>& output) const
 
 Asset::LoadResult JsonAssetBase::loadAsset()
 {
-    if (IsVirtual())
+    if (IsVirtual() || _isVirtualDocument)
         return LoadResult::Ok;
 
     // Load data (raw json file in editor, cooked asset in build game)
@@ -210,6 +225,7 @@ void JsonAssetBase::unload(bool isReloading)
     Data = nullptr;
     DataTypeName.Clear();
     DataEngineBuild = 0;
+    _isVirtualDocument = false;
 }
 
 #if USE_EDITOR

Source/Engine/Content/JsonAsset.cs

@@ -66,5 +66,16 @@ namespace FlaxEngine
             Debug.LogError(string.Format("Missing type '{0}' to create Json Asset instance.", dataTypeName), this);
             return null;
         }
+
+        /// <summary>
+        /// Sets the instance of the asset (for both C# and C++). Doesn't save asset to the file (runtime only).
+        /// </summary>
+        /// <param name="instance">The new instance.</param>
+        public void SetInstance(object instance)
+        {
+            _instance = instance;
+            string str = instance != null ? JsonSerializer.Serialize(instance) : null;
+            Data = str;
+        }
     }
 }

Source/Engine/Content/JsonAsset.h

@@ -15,6 +15,7 @@ API_CLASS(Abstract, NoSpawn) class FLAXENGINE_API JsonAssetBase : public Asset
     DECLARE_SCRIPTING_TYPE_NO_SPAWN(JsonAssetBase);
 protected:
     String _path;
+    bool _isVirtualDocument = false;
 
 protected:
     /// <summary>
@@ -50,6 +51,11 @@ public:
     /// </summary>
     API_PROPERTY() String GetData() const;
 
+    /// <summary>
+    /// The Json data (as string).
+    /// </summary>
+    API_PROPERTY() void SetData(const StringView& value);
+
     /// <summary>
     /// Initializes the virtual Json asset with custom data.
     /// </summary>