Mirrors/inspectrum
2
0
Fork 0
mirror of https://github.com/miek/inspectrum.git synced 2026-03-03 06:54:17 +01:00
Code Issues Packages Projects Releases Wiki Activity

Wrap fftw calls in a class

Browse Source
This commit is contained in:
Mike Walters
2015-08-02 15:16:23 +01:00
parent 35bd613d0d
commit 407c60db85
5 changed files with 57 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
inputsource.cpp
View File

@@ -27,17 +27,11 @@ InputSource::InputSource(const char *filename, int fft_size) {
}
InputSource::~InputSource() {
cleanupFFTW();
delete fft;
munmap(m_data, m_file_size);
fclose(m_file);
}
void InputSource::cleanupFFTW() {
if (m_fftw_plan != nullptr) fftwf_destroy_plan(m_fftw_plan);
if (m_fftw_in != nullptr) fftwf_free(m_fftw_in);
if (m_fftw_out != nullptr) fftwf_free(m_fftw_out);
}
bool InputSource::getSamples(fftwf_complex *dest, int start, int length)
{
if (start + length >= sampleCount)
@@ -48,7 +42,7 @@ bool InputSource::getSamples(fftwf_complex *dest, int start, int length)
}
void InputSource::getViewport(float *dest, int x, int y, int width, int height, int zoom) {
fftwf_complex buffer[m_fft_size];
fftwf_complex *sample_ptr = &m_data[y * getFFTStride()];
for (int i = 0; i < height; i++) {
@@ -56,20 +50,20 @@ void InputSource::getViewport(float *dest, int x, int y, int width, int height,
if (sample_ptr > m_data + (m_file_size/sizeof(fftwf_complex)))
break;
memcpy(m_fftw_in, sample_ptr, m_fft_size * sizeof(fftwf_complex));
memcpy(buffer, sample_ptr, m_fft_size * sizeof(fftwf_complex));
// Apply window
for (int j = 0; j < m_fft_size; j++) {
m_fftw_in[j][0] *= m_window[j];
m_fftw_in[j][1] *= m_window[j];
buffer[j][0] *= m_window[j];
buffer[j][1] *= m_window[j];
}
fftwf_execute(m_fftw_plan);
fft->process(buffer, buffer);
for (int j = x; j < width; j++) {
int k = (j + m_fft_size / 2) % m_fft_size;
float re = m_fftw_out[k][0];
float im = m_fftw_out[k][1];
float re = buffer[k][0];
float im = buffer[k][1];
float mag = sqrt(re * re + im * im) / m_fft_size;
float magdb = 10 * log2(mag) / log2(10);
*dest = magdb;
@@ -88,13 +82,10 @@ int InputSource::getWidth() {
}
void InputSource::setFFTSize(int size) {
cleanupFFTW();
delete fft;
fft = new FFT(size);
m_fft_size = size;
m_fftw_in = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * m_fft_size);
m_fftw_out = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * m_fft_size);
m_fftw_plan = fftwf_plan_dft_1d(m_fft_size, m_fftw_in, m_fftw_out, FFTW_FORWARD, FFTW_MEASURE);
m_window.reset(new float[m_fft_size]);
for (int i = 0; i < m_fft_size; i++) {
m_window[i] = 0.5f * (1.0f - cos(Tau * i / (m_fft_size - 1)));