VolumeFader.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "CoreMinimal.h"
 
 
namespace Audio
{
    enum class EFaderCurve : uint8
    {
        // Linear Fade
        Linear,
 
        // Logarithmic Fade
        Logarithmic,
 
        // S-Curve, Sinusoidal Fade
        SCurve,
 
        // Equal Power, Sinusoidal Fade
        Sin,
 
        Count
    };
 
 
    class FVolumeFader
    {
    public:
        SIGNALPROCESSING_API FVolumeFader();
 
        SIGNALPROCESSING_API void Activate();
 
        SIGNALPROCESSING_API void Deactivate();
 
        SIGNALPROCESSING_API float GetActiveDuration() const;
 
        SIGNALPROCESSING_API float GetVolume() const;
 
        SIGNALPROCESSING_API float GetVolumeAfterTime(float InDeltaTime) const;
 
        SIGNALPROCESSING_API float GetFadeDuration() const;
 
        SIGNALPROCESSING_API EFaderCurve GetCurve() const;
 
        SIGNALPROCESSING_API float GetTargetVolume() const;
 
        SIGNALPROCESSING_API bool IsActive() const;
 
        SIGNALPROCESSING_API bool IsFading() const;
 
        SIGNALPROCESSING_API bool IsFadingIn() const;
 
        SIGNALPROCESSING_API bool IsFadingOut() const;
 
        SIGNALPROCESSING_API void SetActiveDuration(float InDuration);
 
        SIGNALPROCESSING_API void SetVolume(float InVolume);
 
        SIGNALPROCESSING_API void StartFade(float InVolume, float InDuration, EFaderCurve InCurve);
 
        SIGNALPROCESSING_API void StopFade();
 
        SIGNALPROCESSING_API void Update(float InDeltaTime);
 
    private:
        static float AlphaToVolume(float InAlpha, EFaderCurve InCurve, float InStartingValue, float InTarget);
 
        float Alpha;
 
        float Target;
 
        float ActiveDuration;
 
        float FadeDuration;
 
        float Elapsed;
 
        EFaderCurve FadeCurve;
 
        float StartingValue;
    };
} // namespace Audio