Added facilities into PluginInsert for the GUI to gather parts of the real signal...

[ardour.git] / gtk2_ardour / fft.cc

diff --git a/gtk2_ardour/fft.cc b/gtk2_ardour/fft.cc
index eda1a96e3f6c601b6cad76fdd5d80cc15d2db969..f78a1e94ad2f1935313765c16e1e67f8bb452388 100644 (file)
--- a/gtk2_ardour/fft.cc
+++ b/gtk2_ardour/fft.cc
@@ -26,7 +26,8 @@
 FFT::FFT(uint32_t windowSize)
        : _window_size(windowSize),
          _data_size(_window_size/2),
-       _iterations(0)
+       _iterations(0),
+       _hann_window(0)
 {
        _fftInput  = (float *) fftwf_malloc(sizeof(float) * _window_size);
 
@@ -50,12 +51,19 @@ FFT::reset()
 }
 
 void
-FFT::analyze(ARDOUR::Sample *input)
+FFT::analyze(ARDOUR::Sample *input, WindowingType windowing_type)
 {
        _iterations++;
 
        memcpy(_fftInput, input, sizeof(float) * _window_size);
 
+       if (windowing_type == HANN) {
+               float *window = get_hann_window();
+               for (uint32_t i = 0; i < _window_size; i++) {
+                       _fftInput[i] *= window[i];
+               }
+       }
+
        fftwf_execute(_plan);
 
        _power_at_bin[0] += _fftOutput[0] * _fftOutput[0];
@@ -96,9 +104,37 @@ FFT::calculate()
        }
 }
 
+float *
+FFT::get_hann_window()
+{
+       if (_hann_window)
+               return _hann_window;
+
+
+        _hann_window = (float *) malloc(sizeof(float) * _window_size);
+
+       double sum = 0.0;
+        
+        for (uint32_t i=0; i < _window_size; i++) {
+                _hann_window[i]=0.81f * ( 0.5f - (0.5f * (float) cos(2.0f * M_PI * (float)i / (float)(_window_size))));
+                sum += _hann_window[i];
+        }
+
+        double isum = 1.0 / sum;
+        
+        for (uint32_t i=0; i < _window_size; i++) {
+                _hann_window[i] *= isum;
+        }
+
+       return _hann_window;
+}
+
 
 FFT::~FFT()
 {
+       if (_hann_window) {
+               free(_hann_window);
+       }
        fftwf_destroy_plan(_plan);
        free(_power_at_bin);
        free(_phase_at_bin);