Working on MI SetParameter

Plugins/BlueprintMCP/Deprecated/Material_ReparentInstance.h

@@ -0,0 +1,95 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "MCPHandler.h"
+#include "MCPAssetFinder.h"
+#include "MCPUtils.h"
+#include "Materials/Material.h"
+#include "Materials/MaterialInterface.h"
+#include "Materials/MaterialInstanceConstant.h"
+#include "Material_ReparentInstance.generated.h"
+
+
+// ---------------------------------------------------------------------------
+// ---------------------------------------------------------------------------
+// ---------------------------------------------------------------------------
+
+UCLASS()
+class UMCP_Material_ReparentInstance : public UObject, public IMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Description="Material Instance name or path to reparent"))
+	FString MaterialInstance;
+
+	UPROPERTY(meta=(Description="New parent material name or path (Material or Material Instance)"))
+	FString NewParent;
+
+	UPROPERTY(meta=(Optional, Description="If true, validate without applying changes"))
+	bool DryRun = false;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Change the parent material of a Material Instance. "
+			"Validates against circular parent chains.");
+	}
+
+	virtual void Handle(const FJsonObject* Json, FStringBuilderBase& Result) override
+	{
+		// Load the Material Instance
+		MCPAssets<UMaterialInstanceConstant> Assets;
+		if (!Assets.Exact(MaterialInstance).Errors(Result).ENone().ETwo().Load()) return;
+		UMaterialInstanceConstant* MI = Assets.Object();
+
+		// Load new parent (Material or MaterialInstance)
+		MCPAssets<UMaterialInterface> ParentAssets;
+		ParentAssets.NoScans();
+		ParentAssets.Scan<UMaterial>();
+		ParentAssets.Scan<UMaterialInstanceConstant>();
+		if (!ParentAssets.Exact(NewParent).Errors(Result).ENone().ETwo().Load()) return;
+		UMaterialInterface* NewParentObj = ParentAssets.Object();
+
+		// Prevent circular parenting
+		UMaterialInterface* Check = NewParentObj;
+		while (Check)
+		{
+			if (Check == MI)
+			{
+				Result.Appendf(TEXT("ERROR: Reparenting to '%s' would create a circular parent chain.\n"),
+					*NameOf(NewParentObj));
+				return;
+			}
+			UMaterialInstanceConstant* CheckMI = Cast<UMaterialInstanceConstant>(Check);
+			if (!CheckMI) break;
+			Check = CheckMI->Parent;
+		}
+
+		FString OldParentName = MI->Parent ? NameOf(MI->Parent) : TEXT("None");
+
+		if (DryRun)
+		{
+			Result.Appendf(TEXT("[DRY RUN] Would reparent %s: %s -> %s\n"),
+				*MCPUtils::FormatName(MI), *OldParentName, *NameOf(NewParentObj));
+			return;
+		}
+
+		MCPUtils::PreEdit({MI});
+		MI->Parent = NewParentObj;
+		MCPUtils::PostEdit({MI});
+		MCPUtils::SaveGenericPackage(MI);
+
+		Result.Appendf(TEXT("Reparented %s: %s -> %s\n"),
+			*MCPUtils::FormatName(MI), *OldParentName, *NameOf(NewParentObj));
+	}
+
+private:
+	FString NameOf(UMaterialInterface* Obj)
+	{
+		if (UMaterial* M = Cast<UMaterial>(Obj))
+			return MCPUtils::FormatName(M);
+		if (UMaterialInstance* MI = Cast<UMaterialInstance>(Obj))
+			return MCPUtils::FormatName(MI);
+		return Obj->GetPathName();
+	}
+};