Method processAudioBuffer

src/tracks/InstrumentTrack.cpp:161–219

void InstrumentTrack::processAudioBuffer( sampleFrame* buf, const fpp_t frames, NotePlayHandle* n )
{
	// we must not play the sound if this InstrumentTrack is muted...
	if( isMuted() || ( Engine::getSong()->playMode() != Song::Mode_PlayPattern &&
				n && n->isBbTrackMuted() ) || ! m_instrument )
	{
		return;
	}

	// Test for silent input data if instrument provides a single stream only (i.e. driven by InstrumentPlayHandle)
	// We could do that in all other cases as well but the overhead for silence test is bigger than
	// what we potentially save. While playing a note, a NotePlayHandle-driven instrument will produce sound in
	// 99 of 100 cases so that test would be a waste of time.
	if( m_instrument->flags().testFlag( Instrument::IsSingleStreamed ) &&
		MixHelpers::isSilent( buf, frames ) )
	{
		// at least pass one silent buffer to allow
		if( m_silentBuffersProcessed )
		{
			// skip further processing
			return;
		}
		m_silentBuffersProcessed = true;
	}
	else
	{
		m_silentBuffersProcessed = false;
	}

	// if effects "went to sleep" because there was no input, wake them up
	// now
	m_audioPort.effects()->startRunning();

	// get volume knob data
	static const float DefaultVolumeRatio = 1.0f / DefaultVolume;
	/*ValueBuffer * volBuf = m_volumeModel.valueBuffer();
	float v_scale = volBuf
		? 1.0f
		: getVolume() * DefaultVolumeRatio;*/

	// instruments using instrument-play-handles will call this method
	// without any knowledge about notes, so they pass NULL for n, which
	// is no problem for us since we just bypass the envelopes+LFOs
	if( m_instrument->flags().testFlag( Instrument::IsSingleStreamed ) == false && n != NULL )
	{
		const f_cnt_t offset = n->noteOffset();
		m_soundShaping.processAudioBuffer( buf + offset, frames - offset, n );
		const float vol = ( (float) n->getVolume() * DefaultVolumeRatio );
		const panning_t pan = qBound( PanningLeft, n->getPanning(), PanningRight );
		stereoVolumeVector vv = panningToVolumeVector( pan, vol );
		for( f_cnt_t f = offset; f < frames; ++f )
		{
			for( int c = 0; c < 2; ++c )
			{
				buf[f][c] *= vv.vol[c];
			}
		}
	}