biquadfilter.h

Go to the documentation of this file.

// SPDX-FileCopyrightText: Copyright (C) 2019 swift Project Community / Contributors
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-swift-pilot-client-1
 
 
#ifndef SWIFT_SOUND_DSP_BIQUADFILTER_H
#define SWIFT_SOUND_DSP_BIQUADFILTER_H
 
#include "sound/swiftsoundexport.h"
 
namespace swift::sound::dsp
{
    class BiQuadFilter
    {
    public:
        BiQuadFilter() = default;
 
        float transform(float inSample);
 
        void setCoefficients(double aa0, double aa1, double aa2, double b0, double b1, double b2);
        void setLowPassFilter(float sampleRate, float cutoffFrequency, float q);
        void setPeakingEq(float sampleRate, float centreFrequency, float q, float dbGain);
        void setHighPassFilter(float sampleRate, float cutoffFrequency, float q);
 
        static BiQuadFilter lowPassFilter(float sampleRate, float cutoffFrequency, float q);
        static BiQuadFilter highPassFilter(float sampleRate, float cutoffFrequency, float q);
        static BiQuadFilter peakingEQ(float sampleRate, float centreFrequency, float q, float dbGain);
 
    private:
        double m_a0 = 0.0;
        double m_a1 = 0.0;
        double m_a2 = 0.0;
        double m_a3 = 0.0;
        double m_a4 = 0.0;
 
        // state
        float m_x1 = 0.0;
        float m_x2 = 0.0;
        float m_y1 = 0.0;
        float m_y2 = 0.0;
    };
} // ns
 
#endif // SWIFT_SOUND_DSP_BIQUADFILTER_H