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Merge pull request #42804 from RandomShaper/fix_fft_window

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Fix application of window in FFT
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Rémi Verschelde 2020-10-15 13:21:33 +02:00 committed by GitHub
commit e927f54170
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 9 additions and 10 deletions
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19
servers/audio/effects/audio_effect_spectrum_analyzer.cpp
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@ -113,15 +113,15 @@ void AudioEffectSpectrumAnalyzerInstance::process(const AudioFrame *p_src_frames
float *fftw = temporal_fft.ptrw();
for (int i = 0; i < to_fill; i++) { //left and right buffers
float window = -0.5 * Math::cos(2.0 * Math_PI * (double)i / (double)to_fill) + 0.5;
fftw[(i + temporal_fft_pos) * 2] = window * p_src_frames[i].l;
fftw[(i + temporal_fft_pos) * 2 + 1] = 0;
fftw[(i + temporal_fft_pos + fft_size * 2) * 2] = window * p_src_frames[i].r;
fftw[(i + temporal_fft_pos + fft_size * 2) * 2 + 1] = 0;
float window = -0.5 * Math::cos(2.0 * Math_PI * (double)temporal_fft_pos / (double)fft_size) + 0.5;
fftw[temporal_fft_pos * 2] = window * p_src_frames->l;
fftw[temporal_fft_pos * 2 + 1] = 0;
fftw[(temporal_fft_pos + fft_size * 2) * 2] = window * p_src_frames->r;
fftw[(temporal_fft_pos + fft_size * 2) * 2 + 1] = 0;
++p_src_frames;
++temporal_fft_pos;
}
p_src_frames += to_fill;
temporal_fft_pos += to_fill;
p_frame_count -= to_fill;
if (temporal_fft_pos == fft_size * 2) {
@ -134,9 +134,8 @@ void AudioEffectSpectrumAnalyzerInstance::process(const AudioFrame *p_src_frames
for (int i = 0; i < fft_size; i++) {
//abs(vec)/fft_size normalizes each frequency
float window = 1.0; //-.5 * Math::cos(2. * Math_PI * (double)i / (double)fft_size) + .5;
hw[i].l = window * Vector2(fftw[i * 2], fftw[i * 2 + 1]).length() / float(fft_size);
hw[i].r = window * Vector2(fftw[fft_size * 4 + i * 2], fftw[fft_size * 4 + i * 2 + 1]).length() / float(fft_size);
hw[i].l = Vector2(fftw[i * 2], fftw[i * 2 + 1]).length() / float(fft_size);
hw[i].r = Vector2(fftw[fft_size * 4 + i * 2], fftw[fft_size * 4 + i * 2 + 1]).length() / float(fft_size);
}
fft_pos = next; //swap