big directory re-org

brain/src/fft.cpp

@@ -0,0 +1,99 @@
+// Copyright (C) 2015 Foam Kernow
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+#include <fft.h>
+#include <string.h>
+
+#include <iostream>
+
+using namespace spiralcore;
+using namespace std;
+
+static const int MAX_FFT_LENGTH = 4096;
+
+FFT::FFT(u32 length, u32 bins) :
+  m_length(length),
+  m_num_bins(bins),
+  m_in(new double[length]),
+  m_spectrum(new fftw_complex[length]),
+  m_bin(new float[bins])
+{
+  memset(m_spectrum,0,sizeof(fftw_complex)*length);
+  m_plan = fftw_plan_dft_r2c_1d(m_length, m_in, m_spectrum, FFTW_ESTIMATE);
+}
+
+FFT::~FFT()
+{
+  delete[] m_in;
+  fftw_destroy_plan(m_plan);
+}
+
+void FFT::impulse2freq(const float *imp)
+{
+  unsigned int i;
+
+  for (i=0; i<m_length; i++)
+    {
+      m_in[i] = imp[i];
+    }
+
+  fftw_execute(m_plan);
+}
+
+static const float SRATE = 44100;
+
+float FFT::calculate_dominant_freq() {
+  double highest = 0;
+  u32 index = 0;
+  for (u32 i=0; i<m_length/2; ++i) {
+    double t = m_spectrum[i][0]*m_spectrum[i][0];
+    if (t>highest) {
+      index=i;
+      highest=t;
+    }
+  }
+  float freq = index * (SRATE/(float)m_length);
+  if (freq<0.01) freq=0.01;
+  return freq;
+}
+
+void FFT::calculate_bins() {
+  float useful_area = m_length/2;
+
+  for (unsigned int n=0; n<m_num_bins; n++) {
+    float value = 0;
+
+    float f = n/(float)m_num_bins;
+    float t = (n+1)/(float)m_num_bins;
+    //f*=f;
+    //t*=t;
+    u32 from = f*useful_area;
+    u32 to = t*useful_area;
+
+    //cerr<<"fft bin:"<<from<<" "<<to<<" - "<<m_length<<endl;
+
+    for (u32 i=from; i<=to; i++) {
+      if (i<m_length) {
+        value += m_spectrum[i][0]*m_spectrum[i][0];
+      }
+    }
+
+    if (value<0) value=-value;
+    m_bin[n]=value;
+  }
+
+
+}