diff options
Diffstat (limited to 'libs/qm-dsp/base/SincWindow.cpp')
| -rw-r--r-- | libs/qm-dsp/base/SincWindow.cpp | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/libs/qm-dsp/base/SincWindow.cpp b/libs/qm-dsp/base/SincWindow.cpp new file mode 100644 index 0000000000..5d31a631e3 --- /dev/null +++ b/libs/qm-dsp/base/SincWindow.cpp @@ -0,0 +1,45 @@ +/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ + +/* + QM DSP library + Centre for Digital Music, Queen Mary, University of London. + + 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. See the file + COPYING included with this distribution for more information. +*/ + +#include "SincWindow.h" + +#include <cmath> + +void +SincWindow::init() +{ + if (m_length < 1) { + return; + } else if (m_length < 2) { + m_window.push_back(1); + return; + } else { + + int n0 = (m_length % 2 == 0 ? m_length/2 : (m_length - 1)/2); + int n1 = (m_length % 2 == 0 ? m_length/2 : (m_length + 1)/2); + double m = 2 * M_PI / m_p; + + for (int i = 0; i < n0; ++i) { + double x = ((m_length / 2) - i) * m; + m_window.push_back(sin(x) / x); + } + + m_window.push_back(1.0); + + for (int i = 1; i < n1; ++i) { + double x = i * m; + m_window.push_back(sin(x) / x); + } + } +} + |