mirror of
https://gitlab.com/then-try-this/samplebrain.git
synced 2025-05-14 11:27:21 +00:00
100 lines
2.3 KiB
C++
100 lines
2.3 KiB
C++
// Copyright (C) 2022 Then Try This
|
|
//
|
|
// 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;
|
|
}
|
|
|
|
|
|
}
|