More work on graph editing

Plugins/BlueprintMCP/Source/BlueprintMCP/Handlers/GraphNode_Delete.h

@@ -6,6 +6,9 @@
 #include "MCPUtils.h"
 #include "EdGraph/EdGraph.h"
 #include "EdGraph/EdGraphNode.h"
+#include "MaterialGraph/MaterialGraphNode.h"
+#include "Materials/Material.h"
+#include "IMaterialEditor.h"
 #include "GraphNode_Delete.generated.h"
 
 
@@ -47,8 +50,21 @@ public:
 		}
 
 		F.PreEdit();
-		FoundNode->BreakAllNodeLinks();
+
-		Graph->RemoveNode(FoundNode);
+		if (Cast<UMaterialGraphNode>(FoundNode))
+		{
+			// Use the material editor's DeleteNodes to properly remove
+			// both the graph node and the underlying material expression.
+			IMaterialEditor* MatEditor = F.CastEditor<UMaterial, IMaterialEditor>();
+			if (!MatEditor) return;
+			MatEditor->DeleteNodes({FoundNode});
+		}
+		else
+		{
+			FoundNode->BreakAllNodeLinks();
+			Graph->RemoveNode(FoundNode);
+		}
+
 		F.PostEdit();
 
 		Result.Appendf(TEXT("Deleted node '%s' from graph '%s'.\n"), *NodeTitle, *GraphName);

Plugins/BlueprintMCP/Source/BlueprintMCP/Handlers/GraphNode_SetDefaults.h

@@ -0,0 +1,156 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "MCPHandler.h"
+#include "MCPFetcher.h"
+#include "MCPUtils.h"
+#include "EdGraph/EdGraphPin.h"
+#include "EdGraphSchema_K2.h"
+#include "MaterialGraph/MaterialGraphSchema.h"
+#include "MaterialGraph/MaterialGraphNode.h"
+#include "GraphNode_SetDefaults.generated.h"
+
+
+// ---------------------------------------------------------------------------
+// ---------------------------------------------------------------------------
+// ---------------------------------------------------------------------------
+
+USTRUCT()
+struct FSetNodeDefaultEntry
+{
+	GENERATED_BODY()
+
+	UPROPERTY()
+	FString Node;
+
+	UPROPERTY()
+	FString Name;
+
+	UPROPERTY()
+	FString Value;
+};
+
+
+UCLASS()
+class UMCP_GraphNode_SetDefaults : public UObject, public IMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Description="Graph path, e.g. /Game/Foo,graph:EventGraph"))
+	FString Graph;
+
+	UPROPERTY(meta=(Description="Array of {node, name, value} objects"))
+	FMCPJsonArray Pins;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Set the default value of input pins or material expression properties on nodes.");
+	}
+
+	// -----------------------------------------------------------------------
+	// K2 graphs: set pin default values.
+	// -----------------------------------------------------------------------
+
+	void HandleK2Entry(const FSetNodeDefaultEntry& Entry, UEdGraph* GraphObj, const UEdGraphSchema_K2* K2Schema,
+		TSet<UEdGraphNode*>& ModifiedNodes, FStringBuilderBase& Result)
+	{
+		MCPFetcher F(Result, GraphObj);
+		UEdGraphPin* Pin = F.Node(Entry.Node).Pin(Entry.Name).Cast<UEdGraphPin>();
+		if (!Pin) return;
+
+		UEdGraphNode* Node = Pin->GetOwningNode();
+
+		if (Pin->Direction != EGPD_Input)
+		{
+			Result.Appendf(TEXT("error: %s is an output pin\n"), *MCPUtils::FormatName(Pin));
+			return;
+		}
+
+		Pin->Modify();
+
+		FString UseDefaultValue;
+		TObjectPtr<UObject> UseDefaultObject = nullptr;
+		FText UseDefaultText;
+		K2Schema->GetPinDefaultValuesFromString(Pin->PinType, Node, Entry.Value, UseDefaultValue, UseDefaultObject, UseDefaultText, false);
+		FString Error = K2Schema->IsPinDefaultValid(Pin, UseDefaultValue, UseDefaultObject, UseDefaultText);
+		if (!Error.IsEmpty())
+		{
+			Result.Appendf(TEXT("error: %s: %s\n"), *MCPUtils::FormatName(Pin), *Error);
+			return;
+		}
+		K2Schema->TrySetDefaultValue(*Pin, Entry.Value);
+
+		ModifiedNodes.Add(Node);
+	}
+
+	// -----------------------------------------------------------------------
+	// Material graphs: set material expression properties.
+	// -----------------------------------------------------------------------
+
+	void HandleMaterialEntry(const FSetNodeDefaultEntry& Entry, UEdGraph* GraphObj,
+		TSet<UEdGraphNode*>& ModifiedNodes, FStringBuilderBase& Result)
+	{
+		MCPFetcher F(Result, GraphObj);
+		UMaterialGraphNode* MatNode = F.Node(Entry.Node).Cast<UMaterialGraphNode>();
+		if (!MatNode) return;
+		if (!MatNode->MaterialExpression)
+		{
+			Result.Appendf(TEXT("error: %s has no material expression\n"), *MCPUtils::FormatName(MatNode));
+			return;
+		}
+
+		UMaterialExpression* Expression = MatNode->MaterialExpression;
+		FProperty* Prop = MCPUtils::FindPropertyByName(Expression, Entry.Name, Result);
+		if (!Prop) return;
+
+		if (!MCPUtils::SetPropertyValueText(Expression, Prop, Entry.Value, Result))
+			return;
+
+		Expression->ForcePropertyValueChanged(Prop);
+		ModifiedNodes.Add(MatNode);
+	}
+
+	// -----------------------------------------------------------------------
+
+	virtual void Handle(FStringBuilderBase& Result) override
+	{
+		// Fetch the graph once.
+		MCPFetcher GraphFetcher(Result);
+		UEdGraph* GraphObj = GraphFetcher.Walk(Graph).Cast<UEdGraph>();
+		if (!GraphObj) return;
+
+		const UEdGraphSchema* Schema = GraphObj->GetSchema();
+		const UEdGraphSchema_K2* K2Schema = Cast<UEdGraphSchema_K2>(Schema);
+		const UMaterialGraphSchema* MGSchema = Cast<UMaterialGraphSchema>(Schema);
+
+		if (!K2Schema && !MGSchema)
+		{
+			Result.Appendf(TEXT("error: unsupported graph schema %s\n"), *Schema->GetClass()->GetName());
+			return;
+		}
+
+		TSet<UEdGraphNode*> ModifiedNodes;
+
+		GraphFetcher.PreEdit();
+		for (const TSharedPtr<FJsonValue>& PinVal : Pins.Array)
+		{
+			FSetNodeDefaultEntry Entry;
+			if (!MCPUtils::PopulateFromJson(FSetNodeDefaultEntry::StaticStruct(), &Entry, PinVal, Result))
+				continue;
+
+			if (K2Schema)
+				HandleK2Entry(Entry, GraphObj, K2Schema, ModifiedNodes, Result);
+			else if (MGSchema)
+				HandleMaterialEntry(Entry, GraphObj, ModifiedNodes, Result);
+		}
+
+		for (UEdGraphNode* Node : ModifiedNodes)
+		{
+			Node->ReconstructNode();
+		}
+		GraphFetcher.PostEdit();
+
+		Result.Appendf(TEXT("Done.\n"));
+	}
+};

Plugins/BlueprintMCP/Source/BlueprintMCP/Handlers/GraphPin_SetDefault.h

@@ -1,114 +0,0 @@
-#pragma once
-
-#include "CoreMinimal.h"
-#include "MCPHandler.h"
-#include "MCPFetcher.h"
-#include "MCPUtils.h"
-#include "EdGraph/EdGraphPin.h"
-#include "EdGraphSchema_K2.h"
-#include "GraphPin_SetDefault.generated.h"
-
-
-// ---------------------------------------------------------------------------
-// ---------------------------------------------------------------------------
-// ---------------------------------------------------------------------------
-
-USTRUCT()
-struct FSetPinDefaultEntry
-{
-	GENERATED_BODY()
-
-	UPROPERTY()
-	FString Node;
-
-	UPROPERTY()
-	FString Pin;
-
-	UPROPERTY()
-	FString Value;
-};
-
-
-UCLASS()
-class UMCP_GraphPin_SetDefault : public UObject, public IMCPHandler
-{
-	GENERATED_BODY()
-
-public:
-	UPROPERTY(meta=(Description="Graph path, e.g. /Game/Foo,graph:EventGraph"))
-	FString Graph;
-
-	UPROPERTY(meta=(Description="Array of {node, pin, value} objects"))
-	FMCPJsonArray Pins;
-
-	virtual FString GetDescription() const override
-	{
-		return TEXT("Set the default value of input pins on nodes.");
-	}
-
-	virtual void Handle(FStringBuilderBase& Result) override
-	{
-		// Fetch the graph once.
-		MCPFetcher GraphFetcher(Result);
-		UEdGraph* GraphObj = GraphFetcher.Walk(Graph).Cast<UEdGraph>();
-		if (!GraphObj) return;
-
-		int32 SuccessCount = 0;
-		int32 TotalCount = Pins.Array.Num();
-		TSet<UEdGraphNode*> ModifiedNodes;
-
-		GraphFetcher.PreEdit();
-		for (const TSharedPtr<FJsonValue>& PinVal : Pins.Array)
-		{
-			FSetPinDefaultEntry Entry;
-			if (!MCPUtils::PopulateFromJson(FSetPinDefaultEntry::StaticStruct(), &Entry, PinVal, Result))
-				continue;
-
-			MCPFetcher F(Result, GraphObj);
-			UEdGraphPin* Pin = F.Node(Entry.Node).Pin(Entry.Pin).Cast<UEdGraphPin>();
-			if (!Pin) continue;
-
-			UEdGraphNode* Node = Pin->GetOwningNode();
-
-			if (Pin->Direction != EGPD_Input)
-			{
-				Result.Appendf(TEXT("error: %s is an output pin\n"), *MCPUtils::FormatName(Pin));
-				continue;
-			}
-
-			Pin->Modify();
-
-			// K2 schemas support validation before setting; other schemas (e.g. material) don't.
-			const UEdGraphSchema_K2* K2Schema = Cast<UEdGraphSchema_K2>(Node->GetGraph()->GetSchema());
-			if (K2Schema)
-			{
-				FString UseDefaultValue;
-				TObjectPtr<UObject> UseDefaultObject = nullptr;
-				FText UseDefaultText;
-				K2Schema->GetPinDefaultValuesFromString(Pin->PinType, Node, Entry.Value, UseDefaultValue, UseDefaultObject, UseDefaultText, false);
-				FString Error = K2Schema->IsPinDefaultValid(Pin, UseDefaultValue, UseDefaultObject, UseDefaultText);
-				if (!Error.IsEmpty())
-				{
-					Result.Appendf(TEXT("error: %s: %s\n"), *MCPUtils::FormatName(Pin), *Error);
-					continue;
-				}
-				K2Schema->TrySetDefaultValue(*Pin, Entry.Value);
-			}
-			else
-			{
-				Node->GetGraph()->GetSchema()->TrySetDefaultValue(*Pin, Entry.Value);
-			}
-
-			SuccessCount++;
-			ModifiedNodes.Add(Node);
-		}
-
-		for (UEdGraphNode* Node : ModifiedNodes)
-		{
-			Node->ReconstructNode();
-		}
-		GraphFetcher.PostEdit();
-
-		Result.Appendf(TEXT("Set %d/%d pin defaults.\n"), SuccessCount, TotalCount);
-	}
-};

Plugins/BlueprintMCP/Source/BlueprintMCP/Private/BlueprintExporter.cpp

@@ -288,7 +288,7 @@ void FlxBlueprintExporter::EmitMaterialProperty(UMaterialExpression* Expression,
 
 	bool bEditable = !Prop->HasAnyPropertyFlags(CPF_EditConst);
 	Out.Appendf(TEXT("    %s %s %s = %s\n"),
-		bEditable ? TEXT("editable") : TEXT("readonly"),
+		bEditable ? TEXT("mxeditable") : TEXT("mxreadonly"),
 		*MCPUtils::FormatPropertyType(Prop),
 		*MCPUtils::FormatName(Prop),
 		*ValueStr);

Plugins/BlueprintMCP/Source/BlueprintMCP/Private/MCPFetcher.cpp

@@ -11,6 +11,7 @@
 #include "MaterialGraph/MaterialGraph.h"
 #include "MaterialGraph/MaterialGraphNode.h"
 #include "Engine/LevelScriptBlueprint.h"
+#include "Subsystems/AssetEditorSubsystem.h"
 
 MCPFetcher& MCPFetcher::SetError(const FString& Msg)
 {
@@ -86,7 +87,18 @@ MCPFetcher& MCPFetcher::Asset(const FString& PackagePath)
 {
 	SetObj(LoadObject<UObject>(nullptr, *PackagePath));
 	if (!Obj)
-		SetError(FString::Printf(TEXT("Could not load asset '%s'"), *PackagePath));
+		return SetError(FString::Printf(TEXT("Could not load asset '%s'"), *PackagePath));
+
+	OriginalAsset = Obj;
+
+	// Open the editor for this asset (or bring it to front if already open).
+	UAssetEditorSubsystem* Sub = GEditor->GetEditorSubsystem<UAssetEditorSubsystem>();
+	if (!Sub || !Sub->OpenEditorForAsset(Obj))
+		return SetError(FString::Printf(TEXT("Could not open editor for '%s'"), *PackagePath));
+
+	Editor = Sub->FindEditorForAsset(OriginalAsset, false);
+	if (!Editor)
+		return SetError(FString::Printf(TEXT("Could not find editor instance for '%s'"), *PackagePath));
 
 	// If this is a material open in the editor, use the editor's transient copy.
 	if (UMaterial* Mat = ::Cast<UMaterial>(Obj))

Plugins/BlueprintMCP/Source/BlueprintMCP/Private/MCPUtils.cpp

@@ -1126,6 +1126,7 @@ void MCPUtils::PreEdit(const TArray<UObject*>& Objects)
 
 void MCPUtils::PostEdit(const TArray<UObject*>& Objects)
 {
+	TSet<UEdGraph*> Graphs;
 	TSet<UMaterial*> Materials;
 	TSet<UBlueprint*> Blueprints;
 	for (int32 i = Objects.Num() - 1; i >= 0; --i)
@@ -1134,6 +1135,9 @@ void MCPUtils::PostEdit(const TArray<UObject*>& Objects)
 		Obj->PostEditChange();
 		Obj->MarkPackageDirty();
 
+		if (UEdGraph* Graph = Cast<UEdGraph>(Obj))
+			Graphs.Add(Graph);
+
 		if (UBlueprint* BP = Cast<UBlueprint>(Obj))
 			Blueprints.Add(BP);
 
@@ -1141,6 +1145,8 @@ void MCPUtils::PostEdit(const TArray<UObject*>& Objects)
 			if (UMaterial* BaseMat = MatIface->GetMaterial())
 				Materials.Add(BaseMat);
 	}
+	for (UEdGraph* Graph : Graphs)
+		Graph->NotifyGraphChanged();
 	for (UMaterial *Material : Materials)
 		UMaterialEditingLibrary::RebuildMaterialInstanceEditors(Material);
 	for (UBlueprint *Blueprint : Blueprints)

Plugins/BlueprintMCP/Source/BlueprintMCP/Public/MCPFetcher.h

@@ -4,6 +4,7 @@
 #include "MCPUtils.h"
 
 class UEdGraphPin;
+class IAssetEditorInstance;
 
 // Resolves a path string into a UObject or UEdGraphPin.
 //
@@ -29,6 +30,8 @@ class MCPFetcher
 public:
 	bool bError = false;
 	UObject* Obj = nullptr;
+	UObject* OriginalAsset = nullptr;
+	IAssetEditorInstance* Editor = nullptr;
 	UEdGraphPin* ResultPin = nullptr;
 	MCPErrorCallback ErrorCB = nullptr;
 
@@ -69,6 +72,30 @@ public:
 	static const TArray<FWalker>& GetWalkerTable();
 
 	bool Ok() const { return !bError; }
+	UObject* GetAsset() const { return OriginalAsset; }
+	template<class T> T* CastAsset()
+	{
+		if (bError) return nullptr;
+		T* Result = ::Cast<T>(OriginalAsset);
+		if (!Result)
+			SetError(FString::Printf(TEXT("Asset is %s, expected %s"),
+				OriginalAsset ? *OriginalAsset->GetClass()->GetName() : TEXT("null"),
+				*T::StaticClass()->GetName()));
+		return Result;
+	}
+	template<class AssetType, class EditorType>
+	EditorType* CastEditor()
+	{
+		if (bError) return nullptr;
+		if (!OriginalAsset || !OriginalAsset->IsA<AssetType>())
+		{
+			SetError(FString::Printf(TEXT("Asset is %s, expected %s"),
+				OriginalAsset ? *OriginalAsset->GetClass()->GetName() : TEXT("null"),
+				*AssetType::StaticClass()->GetName()));
+			return nullptr;
+		}
+		return static_cast<EditorType*>(Editor);
+	}
 	const TArray<UObject*>& Visited() const { return Chain; }
 	void PreEdit() { MCPUtils::PreEdit(Chain); }
 	void PostEdit() { MCPUtils::PostEdit(Chain); }