UnrealEngineUWP/Engine/Source/Editor/GraphEditor/Private/MaterialGraphConnectionDrawingPolicy.h

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "ConnectionDrawingPolicy.h"

class FSlateWindowElementList;
class UEdGraph;
class UMaterialGraph;
class UMaterialGraphSchema;

/////////////////////////////////////////////////////
// FMaterialGraphConnectionDrawingPolicy

// This class draws the connections for an UEdGraph using a MaterialGraph schema
class FMaterialGraphConnectionDrawingPolicy : public FConnectionDrawingPolicy
{
protected:
	UMaterialGraph* MaterialGraph;
	const UMaterialGraphSchema* MaterialGraphSchema;

	// Each time a knot is encountered, input geometry is compared to output geometry to see if the pins on the knot need to be reversed
	TMap<class UMaterialGraphNode_Knot*, bool> KnotToReversedDirectionMap;

	bool ShouldChangeTangentForKnot(class UMaterialGraphNode_Knot* Knot);
	bool GetAverageConnectedPosition(class UMaterialGraphNode_Knot* Knot, EEdGraphPinDirection Direction, FVector2D& OutPos) const;
	bool FindPinCenter(UEdGraphPin* Pin, FVector2D& OutCenter) const;

public:
	FMaterialGraphConnectionDrawingPolicy(int32 InBackLayerID, int32 InFrontLayerID, float ZoomFactor, const FSlateRect& InClippingRect, FSlateWindowElementList& InDrawElements, UEdGraph* InGraphObj);

	// FConnectionDrawingPolicy interface
	virtual void DetermineWiringStyle(UEdGraphPin* OutputPin, UEdGraphPin* InputPin, /*inout*/ FConnectionParams& Params) override;
	// End of FConnectionDrawingPolicy interface
};