JUCE/modules/juce_audio_formats/sampler/juce_Sampler.cpp

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

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
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   framework to you, and you must discontinue the installation or download
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   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

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

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

namespace juce
{

SamplerSound::SamplerSound (const String& soundName,
                            AudioFormatReader& source,
                            const BigInteger& notes,
                            int midiNoteForNormalPitch,
                            double attackTimeSecs,
                            double releaseTimeSecs,
                            double maxSampleLengthSeconds)
    : name (soundName),
      sourceSampleRate (source.sampleRate),
      midiNotes (notes),
      midiRootNote (midiNoteForNormalPitch)
{
    if (sourceSampleRate > 0 && source.lengthInSamples > 0)
    {
        length = jmin ((int) source.lengthInSamples,
                       (int) (maxSampleLengthSeconds * sourceSampleRate));

        data.reset (new AudioBuffer<float> (jmin (2, (int) source.numChannels), length + 4));

        source.read (data.get(), 0, length + 4, 0, true, true);

        params.attack  = static_cast<float> (attackTimeSecs);
        params.release = static_cast<float> (releaseTimeSecs);
    }
}

SamplerSound::~SamplerSound()
{
}

bool SamplerSound::appliesToNote (int midiNoteNumber)
{
    return midiNotes[midiNoteNumber];
}

bool SamplerSound::appliesToChannel (int /*midiChannel*/)
{
    return true;
}

//==============================================================================
SamplerVoice::SamplerVoice() {}
SamplerVoice::~SamplerVoice() {}

bool SamplerVoice::canPlaySound (SynthesiserSound* sound)
{
    return dynamic_cast<const SamplerSound*> (sound) != nullptr;
}

void SamplerVoice::startNote (int midiNoteNumber, float velocity, SynthesiserSound* s, int /*currentPitchWheelPosition*/)
{
    if (auto* sound = dynamic_cast<const SamplerSound*> (s))
    {
        pitchRatio = std::pow (2.0, (midiNoteNumber - sound->midiRootNote) / 12.0)
                        * sound->sourceSampleRate / getSampleRate();

        sourceSamplePosition = 0.0;
        lgain = velocity;
        rgain = velocity;

        adsr.setSampleRate (sound->sourceSampleRate);
        adsr.setParameters (sound->params);

        adsr.noteOn();
    }
    else
    {
        jassertfalse; // this object can only play SamplerSounds!
    }
}

void SamplerVoice::stopNote (float /*velocity*/, bool allowTailOff)
{
    if (allowTailOff)
    {
        adsr.noteOff();
    }
    else
    {
        clearCurrentNote();
        adsr.reset();
    }
}

void SamplerVoice::pitchWheelMoved (int /*newValue*/) {}
void SamplerVoice::controllerMoved (int /*controllerNumber*/, int /*newValue*/) {}

//==============================================================================
void SamplerVoice::renderNextBlock (AudioBuffer<float>& outputBuffer, int startSample, int numSamples)
{
    if (auto* playingSound = static_cast<SamplerSound*> (getCurrentlyPlayingSound().get()))
    {
        auto& data = *playingSound->data;
        const float* const inL = data.getReadPointer (0);
        const float* const inR = data.getNumChannels() > 1 ? data.getReadPointer (1) : nullptr;

        float* outL = outputBuffer.getWritePointer (0, startSample);
        float* outR = outputBuffer.getNumChannels() > 1 ? outputBuffer.getWritePointer (1, startSample) : nullptr;

        while (--numSamples >= 0)
        {
            auto pos = (int) sourceSamplePosition;
            auto alpha = (float) (sourceSamplePosition - pos);
            auto invAlpha = 1.0f - alpha;

            // just using a very simple linear interpolation here
            float l = (inL[pos] * invAlpha + inL[pos + 1] * alpha);
            float r = (inR != nullptr) ? (inR[pos] * invAlpha + inR[pos + 1] * alpha)
                                       : l;

            auto envelopeValue = adsr.getNextSample();

            l *= lgain * envelopeValue;
            r *= rgain * envelopeValue;

            if (outR != nullptr)
            {
                *outL++ += l;
                *outR++ += r;
            }
            else
            {
                *outL++ += (l + r) * 0.5f;
            }

            sourceSamplePosition += pitchRatio;

            if (sourceSamplePosition > playingSound->length)
            {
                stopNote (0.0f, false);
                break;
            }
        }
    }
}

} // namespace juce