Editor Reference Viewer

Types

• SReferenceViewer
• UEdGraph_ReferenceViewer

Process

The ViewReferences is registered in FAssetManagerEditorCommands::RegisterCommands. Various places (FAssetManagerEditorModule::OnExtendContentBrowserCommands, FAssetManagerEditorModule::OnExtendLevelEditorCommands and FAssetManagerEditorModule::OnExtendAssetEditor) calls in the action lambda FAssetManagerEditorModule::OpenReferenceViewerUI (there are to overloads for this function).

When you invoke the reference viewer from an asset in the Content Browser (here I’m testing with a Blueprint Actor) the SelectedPackages array will contain the full path of the asset (/Game/The/Path/To/MyBpName) and a FReferenceViewerParams struct.

It will convert these paths to FAssetIdentifiers then call the other function overload. If any asset was given and OnCanOpenReferenceViewerUI doesn’t return an error FAssetManagerEditorModule::OpenReferenceViewerTab is called (this is where SReferenceViewer is created).

Then SReferenceViewer::SetGraphRootIdentifiers is called with the Asset Identifiers and the Reference Viewer Params. This will pass them to UEdGraph_ReferenceViewer::SetGraphRoot (A graph created for the reference viewer) and the graph will save the asset ids in CurrentGraphRootIdentifiers.

Still inside SReferenceViewer::SetGraphRootIdentifiers, SReferenceViewer::RebuildGraph will be called which calls UEdGraph_ReferenceViewer::RebuildGraph which calls UEdGraph_ReferenceViewer::RemoveAllNodes. Then the reference viewer will start to populate the Nodes array by calling UEdGraph_ReferenceViewer::ConstructNodes with the CurrentGraphRootIdentifiers. It will then call UEdGraph_ReferenceViewer::RefilterGraph.

Back on UEdGraph_ReferenceViewer::ConstructNodes, for each root asset identifier (for now, our Blueprint) we build a TMap where the key is our asset id and the value is a FReferenceNodeInfo. We then fill the reference node info struct by calling UEdGraph_ReferenceViewer::RebuildGraph.