GENERIC GRAPH / Custom Editor, how do I make new Nodes?

Development Pipeline & Plugins Editor Scripting
1

Hi I am using GitHub - jinyuliao/GenericGraph: Generic graph data structure plugin for ue4 but having trouble to create new Nodes.
I made classes which inherent from those following classes

Editor Module
-UEdNode_GenericGraphNode
-SEdNode_GenericGraphNode
Runtime Module
-UGenericGraphNode

I made a new FGraphPanelNodeFactory

class FGraphPanelNodeFactory_GenericGraphAnswer : public FGraphPanelNodeFactory
{
	virtual TSharedPtr<class SGraphNode> CreateNode(UEdGraphNode* Node) const override
	{
		if (UEdNode_Answer* EdNode_GraphNodeAnwser = Cast<UEdNode_Answer>(Node))
		{
			return SNew(SedNode_Answer, EdNode_GraphNodeAnwser);
		}
		else if (UEdNode_GenericGraphEdge* EdNode_Edge = Cast<UEdNode_GenericGraphEdge>(Node))
		{
			return SNew(SEdNode_GenericGraphEdge, EdNode_Edge);
		}
		return nullptr;
	}
};

And also a FEdGraphSchemaAction.h

USTRUCT()
struct FAssetSchemaAction_GenericGraphAnwser_NewNode : public FEdGraphSchemaAction
{
	GENERATED_USTRUCT_BODY();

public:
	FAssetSchemaAction_GenericGraphAnswer_NewNode(): NodeTemplate(nullptr) {}

	FAssetSchemaAction_GenericGraphAnswer_NewNode(const FText& InNodeCategory, const FText& InMenuDesc, const FText& InToolTip, const int32 InGrouping)
		: FEdGraphSchemaAction(InNodeCategory, InMenuDesc, InToolTip, InGrouping), NodeTemplate(nullptr) {}

	virtual UEdGraphNode* PerformAction(class UEdGraph* ParentGraph, UEdGraphPin* FromPin, const FVector2D Location, bool bSelectNewNode = true) override;
	virtual void AddReferencedObjects(FReferenceCollector& Collector) override;

	UEdNode_Answer* NodeTemplate;
};

And I use the FEdGraphSchemaAction in the UAssetGraphSchema_GenericGraph::GetGraphContextActions

if (!Graph->NodeType->HasAnyClassFlags(CLASS_Abstract))
	{
		//Og Node
		TSharedPtr<FAssetSchemaAction_GenericGraph_NewNode> NewNodeAction(new FAssetSchemaAction_GenericGraph_NewNode(LOCTEXT("GenericGraphNodeAction", "Generic Graph Node Tooltip"), Desc, AddToolTip, 0));
		NewNodeAction->NodeTemplate = NewObject<UEdNode_GenericGraphNode>(ContextMenuBuilder.OwnerOfTemporaries);
		NewNodeAction->NodeTemplate->GenericGraphNode = NewObject<UGenericGraphNode>(NewNodeAction->NodeTemplate, Graph->NodeType);
		NewNodeAction->NodeTemplate->GenericGraphNode->Graph = Graph;
		ContextMenuBuilder.AddAction(NewNodeAction);

		//My new Node <-----------
		TSharedPtr<FAssetSchemaAction_GenericGraphAnswer_NewNode> NewNodeAction2(new FAssetSchemaAction_GenericGraphAnswer_NewNode(LOCTEXT("GenericGraphNodeAction2", "Generic Graph Node Tooltip2"), Desc, AddToolTip, 0));
		NewNodeAction2->NodeTemplate = NewObject<UEdNode_Answer>(ContextMenuBuilder.OwnerOfTemporaries);
		NewNodeAction2->NodeTemplate->GenericGraphNode = NewObject<UGenericGraphNodeAnswer>(NewNodeAction2->NodeTemplate, Graph->NodeType);
		NewNodeAction2->NodeTemplate->GenericGraphNode->Graph = Graph;
		ContextMenuBuilder.AddAction(NewNodeAction2);

		Visited.Add(Graph->NodeType);
	}

If I implement it like this, UE crashes and says that the line is wrong, where I use my runtime class inherented from UGenericGraphNode.

NewNodeAction2->NodeTemplate->GenericGraphNode = NewObject<UGenericGraphNodeAnswer>(NewNodeAction2->NodeTemplate, Graph->NodeType);

The weird thing is that It works, if I use my original runtime class (clearly not the result I want)

NewNodeAction2->NodeTemplate->GenericGraphNode = NewObject<UGenericGraphNode>(NewNodeAction2->NodeTemplate, Graph->NodeType);

What do I do wrong?

2

I could be wrong but maybe The first parameter should be EdGraphNode that instead of Template?
NewNodeAction2->NodeTemplate->GenericGraphNode is the runtime node data?

I made my own GraphEditor and I find Generic Graph very complex for no reason. Here is how I create my Node. I have in C++ all registered Classes Of Runtime Node. Here is my code and How I do it.

H

USTRUCT()
struct FLUIDARCHITECTCOREEDITOR_API FFluidArchitectEditorEdGraphSchemaAction : public FEdGraphSchemaAction
{
	GENERATED_USTRUCT_BODY();

public:
	FFluidArchitectEditorEdGraphSchemaAction() {}

	FFluidArchitectEditorEdGraphSchemaAction(const FText& InNodeCategory, const FText& InMenuDesc, const FText& InToolTip, const int32 InGrouping)
		: FEdGraphSchemaAction(InNodeCategory, InMenuDesc, InToolTip, InGrouping) {}
	virtual UEdGraphNode* PerformAction(class UEdGraph* ParentGraph, UEdGraphPin* FromPin, const FVector2D Location, bool bSelectNewNode = true) override;
	TSubclassOf<UFluidArchitectCoreGraphNodeEvent> GraphNodeEventClass;
};

CPP

UEdGraphNode* FFluidArchitectEditorEdGraphSchemaAction::PerformAction(UEdGraph* ParentGraph, UEdGraphPin* FromPin, const FVector2D Location, bool bSelectNewNode)
{
	UFluidArchitectEditorEdGraphNode* Node = UFluidArchitectEditorEdGraph::CreateTemplateEdGraphNode(ParentGraph);
	Node->GraphNodeEvent = NewObject<UFluidArchitectCoreGraphNodeEvent>(Node,GraphNodeEventClass);
	ParentGraph->AddNode(Node);
	return Node;
}


void UFluidArchitectEditorEdGraphSchema::GetGraphContextActions(FGraphContextMenuBuilder& ContextMenuBuilder) const
{
	auto CurrentAsset = FluidArchitectCoreEditorProfile::CurrentAsset;
	if (!CurrentAsset)
		return;
	
        ContextMenuBuilder.Empty();	
	for (int i = 0; i < CurrentAsset->RegistredGraphNodeEventClasses.Num();i++)
	{
		auto Action = new FFluidArchitectEditorEdGraphSchemaAction(FText::FromString(""), FText::FromString(CurrentAsset->RegistredGraphNodeEventClasses[i].GetDefaultObject()->GetSearchName().ToString()), FText::FromString(""), 0);
		Action->GraphNodeEventClass = CurrentAsset->RegistredGraphNodeEventClasses[i];
		TSharedPtr<FFluidArchitectEditorEdGraphSchemaAction> NewEventNodeAction(Action);
		ContextMenuBuilder.AddAction(NewEventNodeAction);
	}
}
3

As you can see I have one Action for all my nodes and the Class I want to use is inside it. Than in GetGraphContextActions I add multiple actions of it with “GraphNodeEventClass” variable being set and setting action name based on class.

4

Thanks for the help, your code brought me on to the right track. The issue was the “Graph->NodeType” in NewNodeAction2->NodeTemplate->GenericGraphNode = NewObject<UGenericGraphNode>(NewNodeAction2->NodeTemplate, Graph->NodeType); It’s kinda silly to get the NodeType from the Graph, so I removed the “Graph->NodeType” and it works.

1 Like
5

Happy to hear that. Good luck. Unreal has a lot of silly things in there API I feel like.