Smart Default Event Nodes

DefaultEvents.cpp

// Normally it is possible to register each member function to be spawned as default like this
// But it does not work with ForceAsFunction or BlueprintNativeEvents that return value that spawn function graphs 
// FKismetEditorUtilities::RegisterAutoGeneratedDefaultEvent(this, UDynamicAssetFilter::StaticClass(), GET_FUNCTION_NAME_CHECKED(UDynamicAssetFilter, K2_FilterAsset));
//
// By utilizig RegisterOnBlueprintCreatedCallback can track new blueprint creation and do any stuff to blueprints
// for example - finding BlueprintDefaultEvent meta and creating default node or graph for Blueprint(Native|Implementable)Event
// With this hook any BNE/BIE with BlueprintDefaultEvent will be generated into default node or overridden by default function
// No more need to manually register each function
void MODULENAME::RegisterBlueprintDefaultEvents()
{

	IModuleInterface* ModuleThis = this;
	FKismetEditorUtilities::RegisterOnBlueprintCreatedCallback(ModuleThis, UObject::StaticClass(), FKismetEditorUtilities::FOnBlueprintCreated::CreateLambda([ModuleThis](UBlueprint* InBlueprint)
	{
		UEdGraph* EventGraph = FBlueprintEditorUtils::FindEventGraph(InBlueprint);
		// not all blueprints have graphs, also user may have it disabled
		if (!EventGraph || !GetDefault<UBlueprintEditorSettings>()->bSpawnDefaultBlueprintNodes) return;
			
		int32 NodePositionY = 0;
		TArray<FName> AutoSpawnedEventNames;
				
		for (TFieldIterator<UFunction> It(InBlueprint->GeneratedClass, EFieldIterationFlags::IncludeSuper|EFieldIterationFlags::IncludeInterfaces); It; ++It)
		{
			FName EventName = It->GetFName();
			if (It->HasAllFunctionFlags(FUNC_Event|FUNC_BlueprintEvent) && It->FindMetaData(TEXT("BlueprintDefaultEvent"))
				&& !InBlueprint->GeneratedClass->IsFunctionImplementedInScript(EventName) && !AutoSpawnedEventNames.Contains(EventName))
			{
				AutoSpawnedEventNames.Add(EventName);
					
				UFunction* OverrideFunc = nullptr;
				UClass* const OverrideFuncClass = FBlueprintEditorUtils::GetOverrideFunctionClass(InBlueprint, EventName, &OverrideFunc);
				check(OverrideFunc);
				if (UEdGraphSchema_K2::FunctionCanBePlacedAsEvent(OverrideFunc))
				{ // Create new red event node
					FKismetEditorUtilities::AddDefaultEventNode(InBlueprint, EventGraph, OverrideFunc->GetFName(), OverrideFuncClass, NodePositionY);
				}
				else
				{ // Create new function graph
					UEdGraph* const NewGraph = FBlueprintEditorUtils::CreateNewGraph(InBlueprint, OverrideFunc->GetFName(), UEdGraph::StaticClass(), UEdGraphSchema_K2::StaticClass());
					FBlueprintEditorUtils::AddFunctionGraph(InBlueprint, NewGraph, /*bIsUserCreated=*/ false, OverrideFuncClass);
					NewGraph->Modify();
				}
			}
		}
	}));
}

void MODULENAME::UnRegisterBlueprintDefaultEvents()
{
	FKismetEditorUtilities::UnregisterAutoBlueprintNodeCreation(this);
}