Add a custom sprint arm component that can smoothly avoic collisions

Source/StevesUEHelpers/Private/StevesSpringArmComponent.cpp

@@ -0,0 +1,41 @@
+
+#include "StevesSpringArmComponent.h"
+
+
+UStevesSpringArmComponent::UStevesSpringArmComponent()
+{
+	
+}
+
+FVector UStevesSpringArmComponent::BlendLocations(const FVector& DesiredArmLocation,
+	const FVector& TraceHitLocation,
+	bool bHitSomething,
+	float DeltaTime)
+{
+	// These locations are in world space, we only want to blend the arm length, not the rest
+	const FVector Base = Super::BlendLocations(DesiredArmLocation, TraceHitLocation, bHitSomething, DeltaTime);
+
+	if (bEnableSmoothCollisionAvoidance)
+	{
+		// Convert these back to arm lengths
+		// PreviousArmOrigin has been already set and is the world space origin
+		const float TargetArmLen = (Base - PreviousArmOrigin).Length();
+	
+		const float NewArmLen = FMath::FInterpTo(PrevArmLength.Get(TargetArmLen), TargetArmLen, DeltaTime, SmoothCollisionAvoidanceSpeed);
+
+		// Perform the same transformation again using the new arm length
+		// Now offset camera position back along our rotation
+		FVector Ret = PreviousDesiredLoc - PreviousDesiredRot.Vector() * NewArmLen;
+		// Add socket offset in local space
+		Ret += FRotationMatrix(PreviousDesiredRot).TransformVector(SocketOffset);
+
+		PrevArmLength = NewArmLen;
+
+		return Ret;
+	}
+	else
+	{
+		return Base;
+	}
+	
+}

Source/StevesUEHelpers/Public/StevesSpringArmComponent.h

@@ -0,0 +1,34 @@
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "GameFramework/SpringArmComponent.h"
+#include "StevesSpringArmComponent.generated.h"
+
+
+UCLASS(ClassGroup=(Custom), meta=(BlueprintSpawnableComponent))
+class STEVESUEHELPERS_API UStevesSpringArmComponent : public USpringArmComponent
+{
+	GENERATED_BODY()
+public:
+	/// Whether to move the camera smoothly to avoid collisions rather than jumping instantly
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=CameraCollision)
+	uint32 bEnableSmoothCollisionAvoidance : 1 = true;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=CameraCollision)
+	float SmoothCollisionAvoidanceSpeed = 5;
+	
+protected:
+	TOptional<float> PrevArmLength;
+
+
+public:
+	UStevesSpringArmComponent();
+
+protected:
+	virtual FVector BlendLocations(const FVector& DesiredArmLocation,
+		const FVector& TraceHitLocation,
+		bool bHitSomething,
+		float DeltaTime) override;
+};
+