1 files changed, 90 insertions, 0 deletions
diff --git a/src/fft_riff.cpp b/src/fft_riff.cpp
new file mode 100644
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+++ b/src/fft_riff.cpp
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+/*
+    cw_binaural~: a binaural synthesis external for pure data
+    by David Doukhan - david.doukhan@gmail.com - http://www.limsi.fr/Individu/doukhan
+    and Anne Sedes - sedes.anne@gmail.com
+    Copyright (C) 2009-2011  David Doukhan and Anne Sedes
+
+    For more details, see CW_binaural~, a binaural synthesis external for Pure Data
+    David Doukhan and Anne Sedes, PDCON09
+
+
+    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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+
+#include <math.h>
+#include <m_pd.h>
+
+#include "fft_riff.hpp"
+#include "logstring.hpp"
+
+
+FftRiff::FftRiff(int size): GenericRiff(size)
+{
+	delete [] _coeffs;
+	_coeffs = new float[2* size];
+
+	for (int i = 0; i < 2*size; ++i)
+		_coeffs[i] = 0;
+
+	_tmp_input = new float[2 * size];
+	_tmp_output = new float[2 * size];
+	_tmp_rest = new float[2*size];
+	// we divide by size for not having to normalize after a fft + ifft
+	for (int i = 0; i < 2*size; ++i)
+		_tmp_rest[i] = 0;
+}
+
+FftRiff::~FftRiff()
+{
+	delete [] _tmp_input;
+	delete [] _tmp_output;
+	delete [] _tmp_rest;
+}
+
+
+void FftRiff::process(float* input, float* output, int n)
+{
+	int		i;
+
+	for (i = 0; i < n; ++i)
+		_tmp_input[i] = input[i] / (_size * 2);
+	for (i = n; i < _size * 2; ++i)
+		_tmp_input[i] = 0;
+
+	mayer_realfft(2* _size, _tmp_input);
+
+	_tmp_output[0] = _tmp_input[0] * _coeffs[0];
+	_tmp_output[_size] = _tmp_input[_size] * _coeffs[_size];
+
+	/// multiply the spectrum of the input and the hrtf
+	for (int i = 1; i < _size; ++i)
+	{
+		// real part
+		_tmp_output[i] = _tmp_input[i] * _coeffs[i] - _tmp_input[2*_size-i] * _coeffs[2*_size-i];
+		// imag part
+		_tmp_output[2*_size-i] = _tmp_input[i] * _coeffs[2*_size-i] + _tmp_input[2*_size-i] * _coeffs[i];
+	} 
+
+
+	mayer_realifft(2*_size, _tmp_output);
+
+	// output the current block beginning + the corresponding rests
+	for (i = 0; i < n; ++i)
+		output[i] = _tmp_output[i] + _tmp_rest[i];
+	for (i = n; i < 2*_size-n; ++i)
+		_tmp_rest[i-n] = _tmp_rest[i] + _tmp_output[i];
+	for (i = 2*_size - n; i < 2 * _size; ++i)
+		_tmp_rest[i-n] = _tmp_output[i];
+}