Add circuit connection drawing. (#54)

Source/FlowEditor/Private/Graph/FlowGraphConnectionDrawingPolicy.cpp

@@ -100,6 +100,18 @@ void FFlowGraphConnectionDrawingPolicy::BuildPaths()
 	}
 }
 
+void FFlowGraphConnectionDrawingPolicy::DrawConnection(int32 LayerId, const FVector2D& Start, const FVector2D& End,
+	const FConnectionParams& Params)
+{
+	if (UFlowGraphSettings::Get()->ConnectionDrawType == EFlowConnectionDrawType::Default)
+	{
+		FConnectionDrawingPolicy::DrawConnection(LayerId, Start, End, Params);
+		return;
+	}
+
+	Internal_DrawCircuitSpline(LayerId, Start, End, Params);
+}
+
 void FFlowGraphConnectionDrawingPolicy::Draw(TMap<TSharedRef<SWidget>, FArrangedWidget>& InPinGeometries, FArrangedChildren& ArrangedNodes)
 {
 	BuildPaths();
@@ -162,3 +174,49 @@ void FFlowGraphConnectionDrawingPolicy::DetermineWiringStyle(UEdGraphPin* Output
 		}
 	}
 }
+
+void FFlowGraphConnectionDrawingPolicy::Internal_DrawCircuitSpline(const int32& LayerId, const FVector2D& Start, const FVector2D& End, const FConnectionParams& Params) const
+{
+	const FVector2D StartingPoint =  FVector2D(Start.X + UFlowGraphSettings::Get()->ConnectionSpacing.X, Start.Y);
+	const FVector2D EndPoint = FVector2D(End.X - UFlowGraphSettings::Get()->ConnectionSpacing.Y, End.Y);
+	const FVector2D ControlPoint = Internal_GetControlPoint(StartingPoint, EndPoint);
+
+	const FVector2D StartDirection = (Params.StartDirection == EGPD_Output) ? FVector2D(1.0f, 0.0f) : FVector2D(-1.0f, 0.0f);
+	const FVector2D EndDirection = (Params.EndDirection == EGPD_Input) ? FVector2D(1.0f, 0.0f) : FVector2D(-1.0f, 0.0f);
+
+	FSlateDrawElement::MakeDrawSpaceSpline(DrawElementsList, LayerId, Start, StartDirection, StartingPoint, EndDirection, Params.WireThickness, ESlateDrawEffect::None, Params.WireColor);
+	FSlateDrawElement::MakeDrawSpaceSpline(DrawElementsList, LayerId, StartingPoint, StartDirection, ControlPoint, EndDirection, Params.WireThickness, ESlateDrawEffect::None, Params.WireColor);
+	FSlateDrawElement::MakeDrawSpaceSpline(DrawElementsList, LayerId, ControlPoint, StartDirection, EndPoint, EndDirection, Params.WireThickness, ESlateDrawEffect::None, Params.WireColor);
+	FSlateDrawElement::MakeDrawSpaceSpline(DrawElementsList, LayerId, EndPoint, StartDirection, End, EndDirection, Params.WireThickness, ESlateDrawEffect::None, Params.WireColor);
+}
+
+FVector2D FFlowGraphConnectionDrawingPolicy::Internal_GetControlPoint(const FVector2D& Source, const FVector2D& Target) const
+{
+	const FVector2D Delta = Target - Source;
+	const float Tangent = FMath::Tan(UFlowGraphSettings::Get()->ConnectionAngle * (PI / 180.f));
+
+	const float DX = FMath::Abs(Delta.X);
+	const float DY = FMath::Abs(Delta.Y);
+
+	const float SlopeWidth = DY / Tangent;
+	if (DX > SlopeWidth)
+	{
+		return Delta.X > 0.f ? FVector2D(Target.X - SlopeWidth, Source.Y) : FVector2D(Source.X - SlopeWidth, Target.Y);
+	}
+
+	const float SlopeHeight = DX * Tangent;
+	if (DY > SlopeHeight)
+	{
+		if (Delta.Y > 0.f)
+		{
+			return Delta.X < 0.f ? FVector2D(Source.X, Target.Y - SlopeHeight) : FVector2D(Target.X, Source.Y + SlopeHeight);
+		}
+
+		if (Delta.X < 0.f)
+		{
+			return FVector2D(Source.X, Target.Y + SlopeHeight);
+		}
+	}
+
+	return FVector2D(Target.X, Source.Y - SlopeHeight);
+}

Source/FlowEditor/Private/Graph/FlowGraphSettings.cpp

@@ -2,6 +2,9 @@
 
 UFlowGraphSettings::UFlowGraphSettings(const FObjectInitializer& ObjectInitializer)
 	: Super(ObjectInitializer)
+	, ConnectionDrawType(EFlowConnectionDrawType::Circuit)
+	, ConnectionAngle(45.f)
+	, ConnectionSpacing(FVector2D(30.f))
 	, bExposeFlowAssetCreation(true)
 	, bExposeFlowNodeCreation(true)
 	, bShowAssetToolbarAboveLevelEditor(true)

Source/FlowEditor/Public/Graph/FlowGraphConnectionDrawingPolicy.h

@@ -3,6 +3,13 @@
 #include "ConnectionDrawingPolicy.h"
 #include "EdGraphUtilities.h"
 
+UENUM()
+enum class EFlowConnectionDrawType : uint8
+{
+	Default,
+	Circuit
+};
+
 struct FFlowGraphConnectionDrawingPolicyFactory : public FGraphPanelPinConnectionFactory
 {
 	virtual ~FFlowGraphConnectionDrawingPolicyFactory()
@@ -42,7 +49,13 @@ class FFlowGraphConnectionDrawingPolicy : public FConnectionDrawingPolicy
 	void BuildPaths();
 
 	// FConnectionDrawingPolicy interface
+	virtual void DrawConnection(int32 LayerId, const FVector2D& Start, const FVector2D& End, const FConnectionParams& Params) override;
 	virtual void Draw(TMap<TSharedRef<SWidget>, FArrangedWidget>& PinGeometries, FArrangedChildren& ArrangedNodes) override;
 	virtual void DetermineWiringStyle(UEdGraphPin* OutputPin, UEdGraphPin* InputPin, FConnectionParams& Params) override;
 	// End of FConnectionDrawingPolicy interface
+
+private:
+
+	void Internal_DrawCircuitSpline(const int32& LayerId, const FVector2D& Start, const FVector2D& End, const FConnectionParams& Params) const;
+	FVector2D Internal_GetControlPoint(const FVector2D& Source, const FVector2D& Target) const;
 };

Source/FlowEditor/Public/Graph/FlowGraphSettings.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include "FlowGraphConnectionDrawingPolicy.h"
 #include "Engine/DeveloperSettings.h"
 
 #include "FlowTypes.h"
@@ -14,6 +15,15 @@ class UFlowGraphSettings final : public UDeveloperSettings
 	GENERATED_UCLASS_BODY()
 	static UFlowGraphSettings* Get() { return CastChecked<UFlowGraphSettings>(UFlowGraphSettings::StaticClass()->GetDefaultObject()); }
 
+	UPROPERTY(config, EditAnywhere, Category = "Flow Graph")
+	EFlowConnectionDrawType ConnectionDrawType;
+
+	UPROPERTY(config, EditAnywhere, Category = "Flow Graph", meta = (EditCondition = "ConnectionDrawType == EFlowConnectionDrawType::Circuit"))
+	float ConnectionAngle;
+
+	UPROPERTY(config, EditAnywhere, Category = "Flow Graph", meta = (EditCondition = "ConnectionDrawType == EFlowConnectionDrawType::Circuit"))
+	FVector2D ConnectionSpacing;
+
 	/** Show Flow Asset in Flow category of "Create Asset" menu?
 	* Requires restart after making a change. */
 	UPROPERTY(EditAnywhere, config, Category = "Default UI")