SineWaveTableOsc.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
 
namespace Audio
{
    class FWaveTableOsc;
 
 
    // A sinusoidal wave table oscillator class
    class FSineWaveTableOsc
    {
    public:
        // Constructor
        SIGNALPROCESSING_API FSineWaveTableOsc();
 
        // Virtual Destructor
        SIGNALPROCESSING_API virtual ~FSineWaveTableOsc();
 
        // Initialize the wave table oscillator
        SIGNALPROCESSING_API void Init(const float InSampleRate, const float InFrequencyHz, const float InPhase);
 
        // Sets the sample rate of the oscillator.
        SIGNALPROCESSING_API void SetSampleRate(const float InSampleRate);
 
        // Resets the wave table read indices.
        SIGNALPROCESSING_API void Reset();
 
        // Sets the frequency of the wave table oscillator.
        SIGNALPROCESSING_API void SetFrequencyHz(const float InFrequencyHz);
 
        // Returns the frequency of the wave table oscillator.
        float GetFrequencyHz() const { return FrequencyHz; }
        
        // Sets the phase of the wave table oscillator.
        SIGNALPROCESSING_API void SetPhase(const float InPhase);
 
        // Processes the wave table and fills a buffer
        SIGNALPROCESSING_API void Generate(float* OutBuffer, const int32 NumSamples);
 
        // The static sinusoidal wave table 
        static SIGNALPROCESSING_API const TArray<float>& GetWaveTable();
 
    protected:
        SIGNALPROCESSING_API void UpdatePhaseIncrement();
 
        // The wave table buffer
        const TArray<float>& WaveTableBuffer = GetWaveTable();
        
        // The frequency of the output (given the sample rate)
        float FrequencyHz = 440.0f;
 
        // The sample rate of the oscillator
        float SampleRate = 48000.0f;
 
        // Read index
        float ReadIndex = 0.0f;
 
        // The phase increment (based on frequency)
        float PhaseIncrement = 0.0f;
 
        // The initial/cached phase, will be clamped to range 0.0 - 1.0f
        float InitialPhase = 0.0f;
 
        // The instantaneous phase, clamped to range 0.0 - 1.0f
        float InstantaneousPhase = 0.0f;
    };
}