ParamInterpolator.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
 
namespace Audio
{
    class FParam
    {
    public:
        FParam()
            : CurrentValue(0.0f)
            , StartingValue(0.0f)
            , TargetValue(0.0f)
            , DeltaValue(0.0f)
            , bIsInit(true)
        {}
 
        // Set the parameter value to the given target value over the given interpolation frames.
        inline void SetValue(const float InValue, const int32 InNumInterpFrames = 0)
        {
            TargetValue = InValue;
            if (bIsInit || InNumInterpFrames == 0)
            {
                bIsInit = false;
                StartingValue = TargetValue;
                CurrentValue = TargetValue;
                DeltaValue = 0.0f;
            }
            else
            {
                DeltaValue = (InValue - CurrentValue) / (float)InNumInterpFrames;
                StartingValue = CurrentValue;
            }
        }
 
        inline void Init()
        {
            bIsInit = true;
        }
 
        // Resets the delta value back to 0.0. To be called at beginning of callback render.
        inline void Reset()
        {
            DeltaValue = 0.0f;
            CurrentValue = TargetValue;
        }
 
        // Updates the parameter, assumes called in one of the frames.
        inline float Update()
        {
            CurrentValue += DeltaValue;
            return CurrentValue;
        }
 
        // Returns the current value, but does not update the value
        inline float GetValue() const
        {
            return CurrentValue;
        }
 
        // Returns the target value
        inline float GetTarget() const
        {
            return TargetValue;
        }
 
    private:
        float CurrentValue;
        float StartingValue;
        float TargetValue;
        float DeltaValue;
        bool bIsInit;
    };
 
}