From 394f30251a023ef5c74e4e3b56c1e4728950b66f Mon Sep 17 00:00:00 2001
From: Steve Streeting <steve@stevestreeting.com>
Date: Fri, 6 Dec 2024 11:44:47 +0000
Subject: [PATCH] Spring arm can now smoothly change socket / target offsets

---
 .../Private/StevesSpringArmComponent.cpp      | 55 +++++++++++++++++--
 .../Public/StevesSpringArmComponent.h         | 29 +++++++++-
 2 files changed, 77 insertions(+), 7 deletions(-)

diff --git a/Source/StevesUEHelpers/Private/StevesSpringArmComponent.cpp b/Source/StevesUEHelpers/Private/StevesSpringArmComponent.cpp
index b3ce1fa..3fb01d6 100644
--- a/Source/StevesUEHelpers/Private/StevesSpringArmComponent.cpp
+++ b/Source/StevesUEHelpers/Private/StevesSpringArmComponent.cpp
@@ -9,11 +9,36 @@ UStevesSpringArmComponent::UStevesSpringArmComponent(): bEnableSmoothCollisionAv
 {
 }
 
-FVector UStevesSpringArmComponent::BlendLocations(const FVector& DesiredArmLocation,
-	const FVector& TraceHitLocation,
-	bool bHitSomething,
+void UStevesSpringArmComponent::UpdateDesiredArmLocation(bool bDoTrace,
+	bool bDoLocationLag,
+	bool bDoRotationLag,
 	float DeltaTime)
 {
+	// Smooth target & socket offsets
+	if (SmoothTargetOffsetTarget.IsSet())
+	{
+		TargetOffset = FMath::VInterpTo(TargetOffset, SmoothTargetOffsetTarget.GetValue(), DeltaTime, SmoothTargetOffsetSpeed);
+		if (TargetOffset.Equals(SmoothTargetOffsetTarget.GetValue()))
+		{
+			CancelTargetOffsetSmooth();
+		}
+	}
+	if (SmoothSocketOffsetTarget.IsSet())
+	{
+		SocketOffset = FMath::VInterpTo(SocketOffset, SmoothSocketOffsetTarget.GetValue(), DeltaTime, SmoothSocketOffsetSpeed);
+		if (SocketOffset.Equals(SmoothSocketOffsetTarget.GetValue()))
+		{
+			CancelSocketOffsetSmooth();
+		}
+	}
+	Super::UpdateDesiredArmLocation(bDoTrace, bDoLocationLag, bDoRotationLag, DeltaTime);
+}
+
+FVector UStevesSpringArmComponent::BlendLocations(const FVector& DesiredArmLocation,
+                                                  const FVector& TraceHitLocation,
+                                                  bool bHitSomething,
+                                                  float DeltaTime)
+{
 
 #if WITH_EDITORONLY_DATA && ENABLE_VISUAL_LOG
 	if (bHitSomething && bVisualLogCameraCollision)
@@ -49,7 +74,7 @@ FVector UStevesSpringArmComponent::BlendLocations(const FVector& DesiredArmLocat
 		Ret += FRotationMatrix(PreviousDesiredRot).TransformVector(SocketOffset);
 
 		PrevArmLength = NewArmLen;
-
+			
 		return Ret;
 	}
 	else
@@ -58,3 +83,25 @@ FVector UStevesSpringArmComponent::BlendLocations(const FVector& DesiredArmLocat
 	}
 	
 }
+
+void UStevesSpringArmComponent::SetTargetOffsetSmooth(const FVector& NewTargetOffset, float Speed)
+{
+	SmoothTargetOffsetTarget = NewTargetOffset;
+	SmoothTargetOffsetSpeed = Speed;
+}
+
+void UStevesSpringArmComponent::CancelTargetOffsetSmooth()
+{
+	SmoothTargetOffsetTarget.Reset();
+}
+
+void UStevesSpringArmComponent::SetSocketOffsetSmooth(const FVector& NewSocketOffset, float Speed)
+{
+	SmoothSocketOffsetTarget = NewSocketOffset;
+	SmoothSocketOffsetSpeed = Speed;
+}
+
+void UStevesSpringArmComponent::CancelSocketOffsetSmooth()
+{
+	SmoothSocketOffsetTarget.Reset();
+}
diff --git a/Source/StevesUEHelpers/Public/StevesSpringArmComponent.h b/Source/StevesUEHelpers/Public/StevesSpringArmComponent.h
index 2179215..4e8ba6b 100644
--- a/Source/StevesUEHelpers/Public/StevesSpringArmComponent.h
+++ b/Source/StevesUEHelpers/Public/StevesSpringArmComponent.h
@@ -21,6 +21,11 @@ public:
 protected:
 	TOptional<float> PrevArmLength;
 
+	TOptional<FVector> SmoothTargetOffsetTarget;
+	float SmoothTargetOffsetSpeed;
+	TOptional<FVector> SmoothSocketOffsetTarget;
+	float SmoothSocketOffsetSpeed;
+
 #if WITH_EDITORONLY_DATA
 	UPROPERTY(Transient, EditAnywhere, Category=CameraCollision)
 	bool bVisualLogCameraCollision = false;
@@ -29,10 +34,28 @@ protected:
 public:
 	UStevesSpringArmComponent();
 
+	/// Smoothly change the target offset, instead of jumping
+	UFUNCTION(BlueprintCallable, Category="SpringArm")
+	void SetTargetOffsetSmooth(const FVector& NewTargetOffset, float Speed = 5);
+	/// Interrupt a smooth target offset change, freeze where we are
+	UFUNCTION(BlueprintCallable, Category="SpringArm")
+	void CancelTargetOffsetSmooth();
+
+	/// Smoothly change the socket offset, instead of jumping
+	UFUNCTION(BlueprintCallable, Category="SpringArm")
+	void SetSocketOffsetSmooth(const FVector& NewSocketOffset, float Speed = 5);
+	/// Interrupt a smooth socket offset change, freeze where we are
+	UFUNCTION(BlueprintCallable, Category="SpringArm")
+	void CancelSocketOffsetSmooth();
+
 protected:
-	virtual FVector BlendLocations(const FVector& DesiredArmLocation,
-		const FVector& TraceHitLocation,
-		bool bHitSomething,
+	virtual void UpdateDesiredArmLocation(bool bDoTrace,
+		bool bDoLocationLag,
+		bool bDoRotationLag,
 		float DeltaTime) override;
+	virtual FVector BlendLocations(const FVector& DesiredArmLocation,
+	                               const FVector& TraceHitLocation,
+	                               bool bHitSomething,
+	                               float DeltaTime) override;
 };