JUCE/modules/juce_audio_basics/mpe/juce_MPENote.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

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

namespace
{
    uint16 generateNoteID (int midiChannel, int midiNoteNumber) noexcept
    {
        jassert (midiChannel > 0 && midiChannel <= 16);
        jassert (midiNoteNumber >= 0 && midiNoteNumber < 128);

        return uint16 ((midiChannel << 7) + midiNoteNumber);
    }
}

//==============================================================================
MPENote::MPENote (int midiChannel_,
                  int initialNote_,
                  MPEValue noteOnVelocity_,
                  MPEValue pitchbend_,
                  MPEValue pressure_,
                  MPEValue timbre_,
                  KeyState keyState_) noexcept
    : noteID (generateNoteID (midiChannel_, initialNote_)),
      midiChannel (uint8 (midiChannel_)),
      initialNote (uint8 (initialNote_)),
      noteOnVelocity (noteOnVelocity_),
      pitchbend (pitchbend_),
      pressure (pressure_),
      timbre (timbre_),
      noteOffVelocity (MPEValue::minValue()),
      keyState (keyState_)
{
    jassert (keyState != MPENote::off);
    jassert (isValid());
}

MPENote::MPENote() noexcept
    : noteID (0),
      midiChannel (0),
      initialNote (0),
      noteOnVelocity (MPEValue::minValue()),
      pitchbend (MPEValue::centreValue()),
      pressure (MPEValue::centreValue()),
      timbre (MPEValue::centreValue()),
      noteOffVelocity (MPEValue::minValue()),
      keyState (MPENote::off)
{
}

//==============================================================================
bool MPENote::isValid() const noexcept
{
    return midiChannel > 0 && midiChannel <= 16 && initialNote < 128;
}

//==============================================================================
double MPENote::getFrequencyInHertz (double frequencyOfA) const noexcept
{
    double pitchInSemitones = double (initialNote) + totalPitchbendInSemitones;
    return frequencyOfA * std::pow (2.0, (pitchInSemitones - 69.0) / 12.0);
}

//==============================================================================
bool MPENote::operator== (const MPENote& other) const noexcept
{
    jassert (isValid() && other.isValid());
    return noteID == other.noteID;
}

bool MPENote::operator!= (const MPENote& other) const noexcept
{
    jassert (isValid() && other.isValid());
    return noteID != other.noteID;
}

//==============================================================================
//==============================================================================
#if JUCE_UNIT_TESTS

class MPENoteTests : public UnitTest
{
public:
    MPENoteTests() : UnitTest ("MPENote class") {}

    //==============================================================================
    void runTest() override
    {
        beginTest ("getFrequencyInHertz");
        {
            MPENote note;
            note.initialNote = 60;
            note.totalPitchbendInSemitones = -0.5;
            expectEqualsWithinOneCent (note.getFrequencyInHertz(), 254.178);
        }
    }

private:
    //==============================================================================
    void expectEqualsWithinOneCent (double frequencyInHertzActual,
                                    double frequencyInHertzExpected)
    {
        double ratio = frequencyInHertzActual / frequencyInHertzExpected;
        double oneCent = 1.0005946;
        expect (ratio < oneCent);
        expect (ratio > 1.0 / oneCent);
    }
};

static MPENoteTests MPENoteUnitTests;

#endif // JUCE_UNIT_TESTS