WindowFunctions.cpp

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#pragma once
#include <cmath>
 
namespace krotos
{
    namespace WindowFunctions
    {
        std::vector<float> generateWindow(int sizeInSamples, WindowType windowType)
        {
            std::vector<float> window(sizeInSamples, 0.0f);
 
            switch (windowType)
            {
            case WindowType::Hann:
                for (int n = 0; n < sizeInSamples; n++)
                    window[n] = 0.5f * (1.0f - std::cosf((float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                         float(sizeInSamples - 1)));
                break;
            case WindowType::Hamming:
                for (int n = 0; n < sizeInSamples; n++)
                    window[n] = 0.54f - 0.46f * std::cosf((float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                          float(sizeInSamples - 1));
                break;
            case WindowType::Rectangular:
                for (int n = 0; n < sizeInSamples; n++)
                    window[n] = 1.0f;
                break;
            case WindowType::BlackmanHarris:
                for (int n = 0; n < sizeInSamples; n++)
                    window[n] = (0.42323f -
                                 (0.49755f * std::cosf((float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                       float(sizeInSamples - 1))) +
                                 0.07922f * std::cosf((2.0f * float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                      float(sizeInSamples - 1)));
                break;
            case WindowType::None:
                for (int n = 0; n < sizeInSamples; n++)
                    window[n] = 1.0f;
                break;
            }
 
            return window;
        }
 
        Eigen::VectorXf generateWindowEigen(int sizeInSamples, WindowType windowType)
        {
            Eigen::VectorXf window = Eigen::VectorXf::Zero(sizeInSamples);
 
            switch (windowType)
            {
            case WindowType::Hann:
                for (int n = 0; n < sizeInSamples; ++n)
                    window[n] = 0.5f * (1.0f - std::cosf((float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                         float(sizeInSamples - 1)));
                break;
            case WindowType::Hamming:
                for (int n = 0; n < sizeInSamples; ++n)
                    window[n] = 0.54f - 0.46f * std::cosf((float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                          float(sizeInSamples - 1));
                break;
            case WindowType::Rectangular:
                window.setOnes();
                break;
            case WindowType::BlackmanHarris:
                for (int n = 0; n < sizeInSamples; ++n)
                    window[n] = (0.42323f -
                                 (0.49755f * std::cosf((float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                       float(sizeInSamples - 1))) +
                                 0.07922f * std::cosf((2.0f * float(n) * 2.0f * juce::MathConstants<float>::pi) /
                                                      float(sizeInSamples - 1)));
                break;
            case WindowType::None:
                window.setOnes();
                break;
            }
 
            return window;
        }
 
        float getWindowGainCorrection(int sizeInSamples, WindowType windowType)
        {
            float windowGainCorrection = 0.0f;
 
            auto window = generateWindow(sizeInSamples, windowType);
 
            for (float value : window)
            {
                windowGainCorrection += value;
            }
 
            return windowGainCorrection;
        }
    } // namespace WindowFunctions
} // namespace krotos