KwidgetProcessor_Pan.cpp

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namespace krotos
{
    KwidgetProcessor_Pan::KwidgetProcessor_Pan(Kwidget& owner)
        : KwidgetProcessor(owner), m_range(owner.getParameter(Parameters::Pan)->getNormalisableRange())
    {
        addParameterAttachments({{Parameters::Pan, [this](float x) { setPan(x); }, 16}});
    }
 
    void KwidgetProcessor_Pan::prepare(double /*sampleRate*/, int /*samplesPerBlock*/) {}
 
    void KwidgetProcessor_Pan::process(AudioBuffer<float>& buffer)
    {
        auto numSamples = buffer.getNumSamples();
        auto numChannels = buffer.getNumChannels();
        auto bufferPtr = buffer.getArrayOfWritePointers();
 
        if (numChannels < 2)
            return; // you can't pan mono audio
 
        nextBlock(numSamples);
 
        for (int i = 0; i < numSamples; i++)
        {
            nextSample();
 
            bufferPtr[0][i] *= m_linearGainLeft;
            bufferPtr[1][i] *= m_linearGainRight;
        }
    }
 
    void KwidgetProcessor_Pan::setPan(float pan)
    {
        // convert the [-100, 100] pan range to [0, pi/2]
        auto angle = m_range.convertTo0to1(pan) * MathConstants<float>::halfPi;
 
        // set the linear gains using constant power panning
        m_linearGainLeft = std::cos(angle);
        m_linearGainRight = std::sin(angle);
    }
} // namespace krotos