Square.cc

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//-----------------------------------------------------------------------------
//
//  $Id: Square.cc 874 2014-09-08 02:21:29Z weegreenblobbie $
//
//  Copyright (c) 2006 Nick Hilton
//
//  weegreenblobbie_yahoo_com (replace '_' with '@' and '.')
//
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
//
//  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.
//
//  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 Library General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
//-----------------------------------------------------------------------------

#include <Nsound/Buffer.h>
#include <Nsound/Generator.h>
#include <Nsound/Square.h>

#include <cmath>
#include <cstring>
#include <cstdlib>

using namespace Nsound;

//-----------------------------------------------------------------------------
Buffer
drawSquare(
    const float64 & sample_rate,
    const float64 & percent_lambda_1,
    const float64 & amplitude_1,
    const float64 & percent_lambda_2,
    const float64 & percent_lambda_3,
    const float64 & amplitude_3,
    const float64 & percent_lambda_4)
{
    Buffer waveform;

    //    1----2
    //    |    |
    //    |    |
    //    |    |
    //  --1    2--3    4--5
    //            |    |
    //            |    |
    //            |    |
    //            3----4
    //
    //  |-----lambda------|

    // Draw the 5 lines
    Generator line(sample_rate);

    // Line 1
    waveform << line.drawLine(percent_lambda_1, // pt1_time,
                                0.0,
                                0.0);
    // Line 2
    waveform << line.drawLine(percent_lambda_2 - percent_lambda_1, //pt2_time - pt1_time,
                                amplitude_1,
                                amplitude_1);
    // Line 3
    waveform << line.drawLine(percent_lambda_3 - percent_lambda_2, //pt3_time - pt2_time,
                                0.0,
                                0.0);
    // Line 4
    waveform << line.drawLine(percent_lambda_4 - percent_lambda_3, //pt4_time - pt3_time,
                                amplitude_3,
                                amplitude_3);
    // Line 5
    waveform << line.drawLine(1.0 - percent_lambda_4, //pt5_time - pt4_time,
                                0.0,
                                0.0);

    return waveform;
}

//-----------------------------------------------------------------------------
Square::
Square(const float64 & sample_rate) : Generator(sample_rate)
{
    Buffer waveform;

    waveform << drawLine(0.5, 1.0, 1.0) << drawLine(0.5, -1.0, -1.0);

    ctor(sample_rate, waveform);
}

//-----------------------------------------------------------------------------
Square::
Square(
    const float64 & sample_rate,
    const int32 n_harmonics)
    :
    Generator(sample_rate)
{
    // From wikipedia's definition of a square wave.

    float64 Nf = static_cast<float64>(std::abs(n_harmonics));

    if(Nf < 1.0) Nf = 1.0;

    Buffer waveform = Buffer::zeros(static_cast<uint32>(sample_rate_));

    for(float64 k = 1.0; k <= Nf; k += 1.0)
    {
        float64 kk = 2.0 * k - 1.0;

        waveform += drawSine(1.0, kk) / kk;
    }

    waveform *= 4.0 / M_PI;

    ctor(sample_rate, waveform);
}


//-----------------------------------------------------------------------------
Square::
Square(
    const float64 & sample_rate,
    const float64 & percent_lambda_1,
    const float64 & amplitude_1,
    const float64 & percent_lambda_2,
    const float64 & percent_lambda_3,
    const float64 & amplitude_3,
    const float64 & percent_lambda_4) : Generator(sample_rate)
{
    ctor(sample_rate,
        drawSquare(
            sample_rate,
            percent_lambda_1,
            amplitude_1,
            percent_lambda_2,
            percent_lambda_3,
            amplitude_3,
            percent_lambda_4));
}