Line data    Source code

       1              : #pragma once
       2              : 
       3              : #include "common.h"
       4              : #include <array>
       5              : #include <complex>
       6              : 
       7              : namespace Amplitron {
       8              : 
       9              : /**
      10              :  * @brief Performs Fast Fourier Transform (FFT) and frequency magnitude calculations.
      11              :  * Completely decoupled from GUI rendering libraries (ImGui/SDL).
      12              :  */
      13              : class SpectrumAnalyzer {
      14              : public:
      15              :     static constexpr int FFT_SIZE = 2048;
      16              :     static constexpr int FFT_BINS = FFT_SIZE / 2;
      17              :     static constexpr int DISPLAY_BARS = 96;
      18              : 
      19              :     SpectrumAnalyzer();
      20              : 
      21              :     /**
      22              :      * @brief Perform FFT analysis and update the smoothed frequency DB arrays.
      23              :      */
      24              :     void update(const float* input_samples,
      25              :                 const float* output_samples,
      26              :                 int sample_rate,
      27              :                 float dt_seconds);
      28              : 
      29              :     // Getters for display data (so the UI only reads raw arrays)
      30          966 :     const std::array<float, DISPLAY_BARS>& smoothed_input_db() const { return smoothed_input_db_; }
      31          388 :     const std::array<float, DISPLAY_BARS>& smoothed_output_db() const { return smoothed_output_db_; }
      32          196 :     const std::array<float, DISPLAY_BARS>& input_peak_db() const { return input_peak_db_; }
      33          196 :     const std::array<float, DISPLAY_BARS>& output_peak_db() const { return output_peak_db_; }
      34              : 
      35              : private:
      36              :     void compute_spectrum_bars(const float* samples,
      37              :                                int sample_rate,
      38              :                                std::array<float, DISPLAY_BARS>& bars_db);
      39              :     void run_fft(std::array<std::complex<float>, FFT_SIZE>& data) const;
      40              : 
      41              :     std::array<float, FFT_SIZE> window_{};
      42              :     std::array<std::complex<float>, FFT_SIZE> fft_work_{};
      43              : 
      44              :     std::array<float, DISPLAY_BARS> smoothed_input_db_{};
      45              :     std::array<float, DISPLAY_BARS> smoothed_output_db_{};
      46              :     std::array<float, DISPLAY_BARS> input_peak_db_{};
      47              :     std::array<float, DISPLAY_BARS> output_peak_db_{};
      48              : };
      49              : 
      50              : } // namespace Amplitron