JUCE/modules/juce_audio_basics/sources/juce_ToneGeneratorAudioSource.cpp

/*
  ==============================================================================

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE 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.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

  ==============================================================================
*/

ToneGeneratorAudioSource::ToneGeneratorAudioSource()
    : frequency (1000.0),
      sampleRate (44100.0),
      currentPhase (0.0),
      phasePerSample (0.0),
      amplitude (0.5f)
{
}

ToneGeneratorAudioSource::~ToneGeneratorAudioSource()
{
}

//==============================================================================
void ToneGeneratorAudioSource::setAmplitude (const float newAmplitude)
{
    amplitude = newAmplitude;
}

void ToneGeneratorAudioSource::setFrequency (const double newFrequencyHz)
{
    frequency = newFrequencyHz;
    phasePerSample = 0.0;
}

//==============================================================================
void ToneGeneratorAudioSource::prepareToPlay (int /*samplesPerBlockExpected*/,
                                              double sampleRate_)
{
    currentPhase = 0.0;
    phasePerSample = 0.0;
    sampleRate = sampleRate_;
}

void ToneGeneratorAudioSource::releaseResources()
{
}

void ToneGeneratorAudioSource::getNextAudioBlock (const AudioSourceChannelInfo& info)
{
    if (phasePerSample == 0.0)
        phasePerSample = double_Pi * 2.0 / (sampleRate / frequency);

    for (int i = 0; i < info.numSamples; ++i)
    {
        const float sample = amplitude * (float) std::sin (currentPhase);
        currentPhase += phasePerSample;

        for (int j = info.buffer->getNumChannels(); --j >= 0;)
            *info.buffer->getSampleData (j, info.startSample + i) = sample;
    }
}