From 0ca8fe2f45ad7eae65af42427b2e2c68358c9300 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Sat, 31 Dec 2022 00:22:04 +0100
Subject: [PATCH] Fix passing reference types back to the native code from
 scripting event

---
 .../Bindings/BindingsGenerator.Cpp.cs         | 21 ++++++++++++-------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/Source/Tools/Flax.Build/Bindings/BindingsGenerator.Cpp.cs b/Source/Tools/Flax.Build/Bindings/BindingsGenerator.Cpp.cs
index 0fd5ead49..fb641eb83 100644
--- a/Source/Tools/Flax.Build/Bindings/BindingsGenerator.Cpp.cs
+++ b/Source/Tools/Flax.Build/Bindings/BindingsGenerator.Cpp.cs
@@ -99,14 +99,15 @@ namespace Flax.Build.Bindings
             return sb.ToString();
         }
 
-        private static string GenerateCppWrapperNativeToManagedParam(BuildData buildData, StringBuilder contents, TypeInfo paramType, string paramName, ApiTypeInfo caller, bool isOut)
+        private static string GenerateCppWrapperNativeToManagedParam(BuildData buildData, StringBuilder contents, TypeInfo paramType, string paramName, ApiTypeInfo caller, bool isOut, out bool useLocalVar)
         {
+            useLocalVar = false;
             var nativeToManaged = GenerateCppWrapperNativeToManaged(buildData, paramType, caller, out var managedTypeAsNative, null);
             string result;
             if (!string.IsNullOrEmpty(nativeToManaged))
             {
                 result = string.Format(nativeToManaged, paramName);
-                if (managedTypeAsNative[managedTypeAsNative.Length - 1] == '*')
+                if (managedTypeAsNative[managedTypeAsNative.Length - 1] == '*' && !isOut)
                 {
                     // Pass pointer value
                 }
@@ -117,6 +118,7 @@ namespace Flax.Build.Bindings
                         result = string.Format(nativeToManaged, '*' + paramName);
                     contents.Append($"        auto __param_{paramName} = {result};").AppendLine();
                     result = $"&__param_{paramName}";
+                    useLocalVar = true;
                 }
             }
             else
@@ -1253,7 +1255,7 @@ namespace Flax.Build.Bindings
             for (var i = 0; i < functionInfo.Parameters.Count; i++)
             {
                 var parameterInfo = functionInfo.Parameters[i];
-                var paramValue = GenerateCppWrapperNativeToManagedParam(buildData, contents, parameterInfo.Type, parameterInfo.Name, classInfo, parameterInfo.IsOut);
+                var paramValue = GenerateCppWrapperNativeToManagedParam(buildData, contents, parameterInfo.Type, parameterInfo.Name, classInfo, parameterInfo.IsOut, out _);
                 contents.Append($"        params[{i}] = {paramValue};").AppendLine();
             }
 
@@ -1645,7 +1647,8 @@ namespace Flax.Build.Bindings
                     {
                         var paramType = eventInfo.Type.GenericArgs[i];
                         var paramName = "arg" + i;
-                        var paramValue = GenerateCppWrapperNativeToManagedParam(buildData, contents, paramType, paramName, classInfo, false);
+                        var paramIsOut = paramType.IsRef && !paramType.IsConst;
+                        var paramValue = GenerateCppWrapperNativeToManagedParam(buildData, contents, paramType, paramName, classInfo, paramIsOut, out CppParamsThatNeedConversion[i]);
                         contents.Append($"        params[{i}] = {paramValue};").AppendLine();
                     }
                     if (eventInfo.IsStatic)
@@ -1658,13 +1661,15 @@ namespace Flax.Build.Bindings
                     for (var i = 0; i < paramsCount; i++)
                     {
                         var paramType = eventInfo.Type.GenericArgs[i];
-                        if (paramType.IsRef && !paramType.IsConst)
+                        var paramIsOut = paramType.IsRef && !paramType.IsConst;
+                        if (paramIsOut)
                         {
                             // Convert value back from managed to native (could be modified there)
                             paramType.IsRef = false;
                             var managedToNative = GenerateCppWrapperManagedToNative(buildData, paramType, classInfo, out var managedType, null, out _);
                             var passAsParamPtr = managedType.EndsWith("*");
-                            var paramValue = $"({managedType}{(passAsParamPtr ? "" : "*")})params[{i}]";
+                            var useLocalVar = CppParamsThatNeedConversion[i];
+                            var paramValue = useLocalVar ? $"*({managedType}{(passAsParamPtr ? "" : "*")}*)params[{i}]" : $"({managedType}{(passAsParamPtr ? "" : "*")})params[{i}]";
                             if (!string.IsNullOrEmpty(managedToNative))
                             {
                                 if (!passAsParamPtr)
@@ -2379,7 +2384,7 @@ namespace Flax.Build.Bindings
                     if (typeInfo.IsArray)
                     {
                         typeInfo.IsArray = false;
-                        header.Append($"{GenerateCppWrapperNativeToVariantMethodName(typeInfo)}Array(const {typeInfo}* v, const int32 length)").AppendLine();
+                        header.Append($"{GenerateCppWrapperNativeToVariantMethodName(typeInfo)}Array({(typeInfo.IsConst ? "const " : "")}{typeInfo}* v, const int32 length)").AppendLine();
                         header.Append('{').AppendLine();
                         header.Append("    Variant result;").AppendLine();
                         header.Append("    result.SetType(VariantType(VariantType::Array));").AppendLine();
@@ -2392,7 +2397,7 @@ namespace Flax.Build.Bindings
                     else if (typeInfo.Type == "Array" && typeInfo.GenericArgs != null)
                     {
                         var valueType = typeInfo.GenericArgs[0];
-                        header.Append($"{GenerateCppWrapperNativeToVariantMethodName(valueType)}Array(const {valueType}* v, const int32 length)").AppendLine();
+                        header.Append($"{GenerateCppWrapperNativeToVariantMethodName(valueType)}Array({(typeInfo.IsConst ? "const " : "")}{valueType}* v, const int32 length)").AppendLine();
                         header.Append('{').AppendLine();
                         header.Append("    Variant result;").AppendLine();
                         header.Append("    result.SetType(VariantType(VariantType::Array));").AppendLine();