annotate src/window_makers.hpp @ 0:add35537fdbb tip

Initial import

//  Copyright 2011, Ian Hobson.
//
//  This file is part of gpsynth.
//
//  gpsynth 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.
//
//  gpsynth 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 gpsynth in the file COPYING. 
//  If not, see http://www.gnu.org/licenses/.

#pragma once

#include <cmath>
#include <iterator>

namespace dsp {
  
template<typename OutputIterator>
void BlackmanWindow(int size, OutputIterator output) {
  typedef typename std::iterator_traits<OutputIterator>::value_type T;
  T m1 = (M_PI * 2.0) / (size - 1.0);
  T m2 = (M_PI * 4.0) / (size - 1.0);
  for (T i = 0; i < size; i++) {
    *output++ = 0.42 - 0.5 * std::cos(i * m1) + 0.08 * std::cos(i * m2);
  }
}

template<typename OutputIterator>
void HannWindow(int size, OutputIterator output) {
  typedef typename std::iterator_traits<OutputIterator>::value_type T;
  T m = (M_PI * 2.0) / (size - 1.0);
  for (T i = 0; i < size; i++) {
    *output++ = 0.5 - 0.5 * std::cos(i * m);
  }
}

template<typename OutputIterator>
void HammingWindow(int size, OutputIterator output) {
  typedef typename std::iterator_traits<OutputIterator>::value_type T;
  T m = (M_PI * 2.0) / (size - 1.0);
  for (T i = 0; i < size; i++) {
    *output++ = 0.54 - 0.46 * std::cos(i * m);
  }
}

};