Create UFunction through Code

Development Programming & Scripting
1

Does anybody knows how to create UFunction objects and make them show up in a Blueprint’s “Functions” list, using C++ code?!

Note that I don’t mean using UFUNCTION(…) macro in C++, not what I am looking for…
I mean, where are the functions used by the UEditor to add a function to the Blueprint graph when you hit the “+” in Editor, like this:

I want to make an extension capable of adding UFunction to a Blueprint without any C++ parent function, like the Editor does.

2

Hi. It’s easy if you want to do this in editor plugin. There is a code taken from UEditor which makes a new function here:

			const UEdGraphSchema_K2* K2Schema = GetDefault<UEdGraphSchema_K2>();
			UEdGraph* UCSGraph = FBlueprintEditorUtils::CreateNewGraph(BlueprintObj, K2Schema->FN_UserConstructionScript, UEdGraph::StaticClass(), UEdGraphSchema_K2::StaticClass());
			FBlueprintEditorUtils::AddFunctionGraph(BlueprintObj, UCSGraph, /*bIsUserCreated=*/ false, AActor::StaticClass());
			UCSGraph->bAllowDeletion = false;

BlueprintObj variable declared as UBlueprint*. bAllowDeletion don’t allow user to delete this function.
To view great example of programmatically creation and filling function with nodes you have to find “FBlueprintEditor::CollapseSelectionToFunction” function in source code.

3

In theory this should work; but I am unable to get the UBlueprint* from the object being edited on the customization panel.

All methods I’ve tried casting to UBlueprint* are just failing without ConstructionHelpers.

4

Maybe it will be helpful:

UBlueprint* GetBlueprintForObject(UObject* ParentObject)
{
	UBlueprint* ParentBlueprint = NULL;

	if (ParentObject != NULL)
	{
		ParentBlueprint = Cast<UBlueprint>(ParentObject);
		if (ParentBlueprint == NULL)
		{
			ParentBlueprint = Cast<UBlueprint>(ParentObject->GetClass()->ClassGeneratedBy);
		}
	}

	return ParentBlueprint;
}
5

This is working beautifully!

http://i1234.photobucket.com/albums/ff408/BrUnOXaVIeR/FSMAutoGenerateFunctions_zpsiua76utt.gif

Just one more thing I’m struggling with though…
Would be perfect if I could as well set the Category for the generated blueprint function; I tried UField or UFunction → SetMetadata(), but it didn’t work… Any ideas?

6

This is working beautifully!

Just one more thing I’m struggling with though…
Would be perfect if I could as well set the Category for the generated blueprint function; I tried UField or UFunction → SetMetadata(), but it didn’t work… Any ideas?

7

It seems BP compiler takes whole metadata for functions from the entry point nodes. You can try to get entry point node from a function graph and set metadata there:

	TArray<const UK2Node_FunctionEntry*> EntryPoints;
	Graph->GetNodesOfClass(EntryPoints);

There could be a lot of entry points in the graph, but separate function graphs have only one entry normally. FunctionEntry node have its own MetaData entry which is visible in the blueprint editor.

8

It… just works! :smiley:
Thank you so much, I would upvote a hundred times if I could, thanks again!