root/trunk/libs/hydrogen/src/sampler/sampler.cpp @ 371

/*
 * Hydrogen
 * Copyright(c) 2002-2008 by Alex >Comix< Cominu [comix@users.sourceforge.net]
 *
 * http://www.hydrogen-music.org
 *
 * 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 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 <cassert>
#include <cmath>

#include <hydrogen/sampler/Sampler.h>
#include <hydrogen/adsr.h>
#include <hydrogen/data_path.h>
#include <hydrogen/audio_engine.h>
#include <hydrogen/IO/JackOutput.h>

#include <hydrogen/globals.h>
#include <hydrogen/Song.h>
#include <hydrogen/note.h>
#include <hydrogen/instrument.h>
#include <hydrogen/sample.h>
#include <hydrogen/fx/Effects.h>
#include <hydrogen/hydrogen.h>
#include <hydrogen/Preferences.h>

namespace H2Core
{

inline static float linear_interpolation( float fVal_A, float fVal_B, float fVal )
{
        return fVal_A * ( 1 - fVal ) + fVal_B * fVal;
//      return fVal_A + fVal * ( fVal_B - fVal_A );
//      return fVal_A + ((fVal_B - fVal_A) * fVal);
}



Sampler::Sampler()
                : Object( "Sampler" )
                , __main_out_L( NULL )
                , __main_out_R( NULL )
                , __audio_output( NULL )
                , __preview_instrument( NULL )
{
        INFOLOG( "INIT" );

        __main_out_L = new float[ MAX_BUFFER_SIZE ];
        __main_out_R = new float[ MAX_BUFFER_SIZE ];

        // instrument used in file preview
        QString sEmptySampleFilename = DataPath::get_data_path() + "/emptySample.wav";
        __preview_instrument = new Instrument( sEmptySampleFilename, "preview", new ADSR() );
        __preview_instrument->set_volume( 0.8 );
        __preview_instrument->set_layer( new InstrumentLayer( Sample::load( sEmptySampleFilename ) ), 0 );
}



Sampler::~Sampler()
{
        INFOLOG( "DESTROY" );

        delete[] __main_out_L;
        delete[] __main_out_R;

        delete __preview_instrument;
        __preview_instrument = NULL;
}

// perche' viene passata anche la canzone? E' davvero necessaria?
void Sampler::process( uint32_t nFrames, Song* pSong )
{
        //infoLog( "[process]" );
        assert( __audio_output );

        memset( __main_out_L, 0, nFrames * sizeof( float ) );
        memset( __main_out_R, 0, nFrames * sizeof( float ) );


#ifdef JACK_SUPPORT
        int numtracks = ( ( JackOutput* )__audio_output )->getNumTracks( );

        if ( __audio_output->has_track_outs() ) {
                for(int nTrack = 0; nTrack < numtracks; nTrack++) {
                        memset( __track_out_L[nTrack], 0, ( ( JackOutput* )__audio_output )->getBufferSize( ) * sizeof( float ) );
                        memset( __track_out_R[nTrack], 0, ( ( JackOutput* )__audio_output )->getBufferSize( ) * sizeof( float ) );
                }
        }
#endif // JACK_SUPPORT

        // Max notes limit
        int m_nMaxNotes = Preferences::getInstance()->m_nMaxNotes;
        while ( ( int )__playing_notes_queue.size() > m_nMaxNotes ) {
                Note *oldNote = __playing_notes_queue[ 0 ];
                __playing_notes_queue.erase( __playing_notes_queue.begin() );
                oldNote->get_instrument()->dequeue();
                delete oldNote; // FIXME: send note-off instead of removing the note from the list?
        }


        // eseguo tutte le note nella lista di note in esecuzione
        unsigned i = 0;
        Note* pNote;
        while ( i < __playing_notes_queue.size() ) {
                pNote = __playing_notes_queue[ i ];             // recupero una nuova nota
                unsigned res = __render_note( pNote, nFrames, pSong );
                if ( res == 1 ) {       // la nota e' finita
                        __playing_notes_queue.erase( __playing_notes_queue.begin() + i );
                        pNote->get_instrument()->dequeue();
                        delete pNote;
                        pNote = NULL;
                } else {
                        ++i; // carico la prox nota
                }
        }
}



void Sampler::note_on( Note *note )
{
        //infoLog( "[noteOn]" );
        assert( note );

        // mute groups
        Instrument *pInstr = note->get_instrument();
        if ( pInstr->get_mute_group() != -1 ) {
                // remove all notes using the same mute group
                for ( unsigned j = 0; j < __playing_notes_queue.size(); j++ ) { // delete older note
                        Note *pNote = __playing_notes_queue[ j ];

                        if ( ( pNote->get_instrument() != pInstr )  && ( pNote->get_instrument()->get_mute_group() == pInstr->get_mute_group() ) ) {
                                //warningLog("release");
                                pNote->m_adsr.release();
                        }
                }
        }

        __playing_notes_queue.push_back( note );
}



void Sampler::note_off( Note* note )
{
        UNUSED( note );
        ERRORLOG( "not implemented yet" );
}



/// Render a note
/// Return 0: the note is not ended
/// Return 1: the note is ended
unsigned Sampler::__render_note( Note* pNote, unsigned nBufferSize, Song* pSong )
{
        //infoLog( "[renderNote] instr: " + pNote->getInstrument()->m_sName );
        assert( pSong );

        unsigned int nFramepos;
        Hydrogen* pEngine = Hydrogen::get_instance();
        if (  pEngine->getState() == STATE_PLAYING ) {
                nFramepos = __audio_output->m_transport.m_nFrames;
        } else {
                // use this to support realtime events when not playing
                nFramepos = pEngine->getRealtimeFrames();
        }


        Instrument *pInstr = pNote->get_instrument();
        if ( !pInstr ) {
                ERRORLOG( "NULL instrument" );
                return 1;
        }

        float fLayerGain = 1.0;
        float fLayerPitch = 0.0;

        // scelgo il sample da usare in base alla velocity
        Sample *pSample = NULL;
        for ( unsigned nLayer = 0; nLayer < MAX_LAYERS; ++nLayer ) {
                InstrumentLayer *pLayer = pInstr->get_layer( nLayer );
                if ( pLayer == NULL ) continue;

                if ( ( pNote->get_velocity() >= pLayer->get_start_velocity() ) && ( pNote->get_velocity() <= pLayer->get_end_velocity() ) ) {
                        pSample = pLayer->get_sample();
                        fLayerGain = pLayer->get_gain();
                        fLayerPitch = pLayer->get_pitch();
                        break;
                }
        }
        if ( !pSample ) {
                QString dummy = QString( "NULL sample for instrument %1. Note velocity: %2" ).arg( pInstr->get_name() ).arg( pNote->get_velocity() );
                WARNINGLOG( dummy );
                return 1;
        }

        if ( pNote->m_fSamplePosition >= pSample->get_n_frames() ) {
                WARNINGLOG( "sample position out of bounds. The layer has been resized during note play?" );
                return 1;
        }

        int noteStartInFrames = ( int ) ( pNote->get_position() * __audio_output->m_transport.m_nTickSize ) + pNote->m_nHumanizeDelay;

        int nInitialSilence = 0;
        if ( noteStartInFrames > ( int ) nFramepos ) {  // scrivo silenzio prima dell'inizio della nota
                nInitialSilence = noteStartInFrames - nFramepos;
                int nFrames = nBufferSize - nInitialSilence;
                if ( nFrames < 0 ) {
                        int noteStartInFramesNoHumanize = ( int )pNote->get_position() * __audio_output->m_transport.m_nTickSize;
                        if ( noteStartInFramesNoHumanize > ( int )( nFramepos + nBufferSize ) ) {
                                // this note is not valid. it's in the future...let's skip it....
                                ERRORLOG( QString( "Note pos in the future?? Current frames: %1, note frame pos: %2" ).arg( nFramepos ).arg(noteStartInFramesNoHumanize ) );
                                //pNote->dumpInfo();
                                return 1;
                        }
                        // delay note execution
                        //INFOLOG( "Delaying note execution. noteStartInFrames: " + to_string( noteStartInFrames ) + ", nFramePos: " + to_string( nFramepos ) );
                        return 0;
                }
        }

        float cost_L = 1.0f;
        float cost_R = 1.0f;
        float cost_track_L = 1.0f;
        float cost_track_R = 1.0f;
        float fSendFXLevel_L = 1.0f;
        float fSendFXLevel_R = 1.0f;

        if ( pInstr->is_muted() || pSong->__is_muted ) {        // is instrument muted?
                cost_L = 0.0;
                cost_R = 0.0;
                if ( Preferences::getInstance()->m_nJackTrackOutputMode == 0 ) {
                // Post-Fader
                        cost_track_L = 0.0;
                        cost_track_R = 0.0;
                }

                fSendFXLevel_L = 0.0f;
                fSendFXLevel_R = 0.0f;
        } else {        // Precompute some values...
                cost_L = cost_L * pNote->get_velocity();                // note velocity
                cost_L = cost_L * pNote->get_pan_l();           // note pan
                cost_L = cost_L * fLayerGain;                           // layer gain
                cost_L = cost_L * pInstr->get_pan_l();          // instrument pan
                cost_L = cost_L * pInstr->get_gain();           // instrument gain
                fSendFXLevel_L = cost_L;

                cost_L = cost_L * pInstr->get_volume();         // instrument volume
                if ( Preferences::getInstance()->m_nJackTrackOutputMode == 0 ) {
                // Post-Fader
                        cost_track_L = cost_L * 2;
                }
                cost_L = cost_L * pSong->get_volume();  // song volume
                cost_L = cost_L * 2; // max pan is 0.5


                cost_R = cost_R * pNote->get_velocity();                // note velocity
                cost_R = cost_R * pNote->get_pan_r();           // note pan
                cost_R = cost_R * fLayerGain;                           // layer gain
                cost_R = cost_R * pInstr->get_pan_r();          // instrument pan
                cost_R = cost_R * pInstr->get_gain();           // instrument gain
                fSendFXLevel_R = cost_R;

                cost_R = cost_R * pInstr->get_volume();         // instrument volume
                if ( Preferences::getInstance()->m_nJackTrackOutputMode == 0 ) {
                // Post-Fader
                        cost_track_R = cost_R * 2;
                }
                cost_R = cost_R * pSong->get_volume();  // song pan
                cost_R = cost_R * 2; // max pan is 0.5
        }

        // direct track outputs only use velocity
        if ( Preferences::getInstance()->m_nJackTrackOutputMode == 1 ) {
                cost_track_L = cost_track_L * pNote->get_velocity();
                cost_track_L = cost_track_L * fLayerGain;
                cost_track_R = cost_track_L;
        }

        // Se non devo fare resample (drumkit) posso evitare di utilizzare i float e gestire il tutto in
        // maniera ottimizzata
        //      constant^12 = 2, so constant = 2^(1/12) = 1.059463.
        //      float nStep = 1.0;1.0594630943593

        float fTotalPitch = pNote->m_noteKey.m_nOctave * 12 + pNote->m_noteKey.m_key;
        fTotalPitch += pNote->get_pitch();
        fTotalPitch += fLayerPitch;

        //_INFOLOG( "total pitch: " + to_string( fTotalPitch ) );

        if ( fTotalPitch == 0.0 && pSample->get_sample_rate() == __audio_output->getSampleRate() ) {    // NO RESAMPLE
                return __render_note_no_resample( pSample, pNote, nBufferSize, nInitialSilence, cost_L, cost_R, cost_track_L, cost_track_R, fSendFXLevel_L, fSendFXLevel_R, pSong );
        } else {        // RESAMPLE
                return __render_note_resample( pSample, pNote, nBufferSize, nInitialSilence, cost_L, cost_R, cost_track_L, cost_track_R, fLayerPitch, fSendFXLevel_L, fSendFXLevel_R, pSong );
        }
}




int Sampler::__render_note_no_resample(
    Sample *pSample,
    Note *pNote,
    int nBufferSize,
    int nInitialSilence,
    float cost_L,
    float cost_R,
    float cost_track_L,
    float cost_track_R,
    float fSendFXLevel_L,
    float fSendFXLevel_R,
    Song* pSong
)
{
        int retValue = 1; // the note is ended

        int nNoteLength = -1;
        if ( pNote->get_lenght() != -1 ) {
                nNoteLength = ( int )( pNote->get_lenght() * __audio_output->m_transport.m_nTickSize );
        }

        int nAvail_bytes = pSample->get_n_frames() - ( int )pNote->m_fSamplePosition;   // verifico il numero di frame disponibili ancora da eseguire

        if ( nAvail_bytes > nBufferSize - nInitialSilence ) {   // il sample e' piu' grande del buffersize
                // imposto il numero dei bytes disponibili uguale al buffersize
                nAvail_bytes = nBufferSize - nInitialSilence;
                retValue = 0; // the note is not ended yet
        }

        //ADSR *pADSR = pNote->m_pADSR;

        int nInitialBufferPos = nInitialSilence;
        int nInitialSamplePos = ( int )pNote->m_fSamplePosition;
        int nSamplePos = nInitialSamplePos;
        int nTimes = nInitialBufferPos + nAvail_bytes;
        int nInstrument = pSong->get_instrument_list()->get_pos( pNote->get_instrument() );

        // filter
        bool bUseLPF = pNote->get_instrument()->is_filter_active();
        float fResonance = pNote->get_instrument()->get_filter_resonance();
        float fCutoff = pNote->get_instrument()->get_filter_cutoff();

        float *pSample_data_L = pSample->get_data_l();
        float *pSample_data_R = pSample->get_data_r();

        float fInstrPeak_L = pNote->get_instrument()->get_peak_l(); // this value will be reset to 0 by the mixer..
        float fInstrPeak_R = pNote->get_instrument()->get_peak_r(); // this value will be reset to 0 by the mixer..

        float fADSRValue;
        float fVal_L;
        float fVal_R;

        /*
         * nInstrument could be -1 if the instrument is not found in the current drumset.
         * This happens when someone is using the prelistening function of the soundlibrary.
         */

        if( nInstrument < 0 ) {
                nInstrument = 0;
        }


        for ( int nBufferPos = nInitialBufferPos; nBufferPos < nTimes; ++nBufferPos ) {
                if ( ( nNoteLength != -1 ) && ( nNoteLength <= pNote->m_fSamplePosition )  ) {
                        if ( pNote->m_adsr.release() == 0 ) {
                                retValue = 1;   // the note is ended
                        }
                }

                fADSRValue = pNote->m_adsr.get_value( 1 );
                fVal_L = pSample_data_L[ nSamplePos ] * fADSRValue;
                fVal_R = pSample_data_R[ nSamplePos ] * fADSRValue;

                // Low pass resonant filter
                if ( bUseLPF ) {
                        pNote->m_fBandPassFilterBuffer_L = fResonance * pNote->m_fBandPassFilterBuffer_L + fCutoff * ( fVal_L - pNote->m_fLowPassFilterBuffer_L );
                        pNote->m_fLowPassFilterBuffer_L += fCutoff * pNote->m_fBandPassFilterBuffer_L;
                        fVal_L = pNote->m_fLowPassFilterBuffer_L;

                        pNote->m_fBandPassFilterBuffer_R = fResonance * pNote->m_fBandPassFilterBuffer_R + fCutoff * ( fVal_R - pNote->m_fLowPassFilterBuffer_R );
                        pNote->m_fLowPassFilterBuffer_R += fCutoff * pNote->m_fBandPassFilterBuffer_R;
                        fVal_R = pNote->m_fLowPassFilterBuffer_R;
                }

                if ( __audio_output->has_track_outs() ) {
#ifdef JACK_SUPPORT
                        assert( __track_out_L[ nInstrument ] );
                        assert( __track_out_R[ nInstrument ] );
                        __track_out_L[ nInstrument ][nBufferPos] += fVal_L * cost_track_L;
                        __track_out_R[ nInstrument ][nBufferPos] += fVal_R * cost_track_R;
#endif
                }

                fVal_L = fVal_L * cost_L;
                fVal_R = fVal_R * cost_R;

                // update instr peak
                if ( fVal_L > fInstrPeak_L ) {
                        fInstrPeak_L = fVal_L;
                }
                if ( fVal_R > fInstrPeak_R ) {
                        fInstrPeak_R = fVal_R;
                }

                // to main mix
                __main_out_L[nBufferPos] += fVal_L;
                __main_out_R[nBufferPos] += fVal_R;

                ++nSamplePos;
        }
        pNote->m_fSamplePosition += nAvail_bytes;
        pNote->get_instrument()->set_peak_l( fInstrPeak_L );
        pNote->get_instrument()->set_peak_r( fInstrPeak_R );


#ifdef LADSPA_SUPPORT
        // LADSPA
        for ( unsigned nFX = 0; nFX < MAX_FX; ++nFX ) {
                LadspaFX *pFX = Effects::getInstance()->getLadspaFX( nFX );

                float fLevel = pNote->get_instrument()->get_fx_level( nFX );

                if ( ( pFX ) && ( fLevel != 0.0 ) ) {
                        fLevel = fLevel * pFX->getVolume();
                        float *pBuf_L = pFX->m_pBuffer_L;
                        float *pBuf_R = pFX->m_pBuffer_R;

//                      float fFXCost_L = cost_L * fLevel;
//                      float fFXCost_R = cost_R * fLevel;
                        float fFXCost_L = fLevel * fSendFXLevel_L;
                        float fFXCost_R = fLevel * fSendFXLevel_R;

                        int nBufferPos = nInitialBufferPos;
                        int nSamplePos = nInitialSamplePos;
                        for ( int i = 0; i < nAvail_bytes; ++i ) {
                                pBuf_L[ nBufferPos ] += pSample_data_L[ nSamplePos ] * fFXCost_L;
                                pBuf_R[ nBufferPos ] += pSample_data_R[ nSamplePos ] * fFXCost_R;
                                ++nSamplePos;
                                ++nBufferPos;
                        }
                }
        }
        // ~LADSPA
#endif

        return retValue;
}



int Sampler::__render_note_resample(
    Sample *pSample,
    Note *pNote,
    int nBufferSize,
    int nInitialSilence,
    float cost_L,
    float cost_R,
    float cost_track_L,
    float cost_track_R,
    float fLayerPitch,
    float fSendFXLevel_L,
    float fSendFXLevel_R,
    Song* pSong
)
{
        int nNoteLength = -1;
        if ( pNote->get_lenght() != -1 ) {
                nNoteLength = ( int )( pNote->get_lenght() * __audio_output->m_transport.m_nTickSize );
        }
        float fNotePitch = pNote->get_pitch() + fLayerPitch;
        fNotePitch += pNote->m_noteKey.m_nOctave * 12 + pNote->m_noteKey.m_key;

        //_INFOLOG( "pitch: " + to_string( fNotePitch ) );

        float fStep = pow( 1.0594630943593, ( double )fNotePitch );
        fStep *= ( float )pSample->get_sample_rate() / __audio_output->getSampleRate(); // Adjust for audio driver sample rate

        int nAvail_bytes = ( int )( ( float )( pSample->get_n_frames() - pNote->m_fSamplePosition ) / fStep );  // verifico il numero di frame disponibili ancora da eseguire

        int retValue = 1; // the note is ended
        if ( nAvail_bytes > nBufferSize - nInitialSilence ) {   // il sample e' piu' grande del buffersize
                // imposto il numero dei bytes disponibili uguale al buffersize
                nAvail_bytes = nBufferSize - nInitialSilence;
                retValue = 0; // the note is not ended yet
        }

//      ADSR *pADSR = pNote->m_pADSR;

        int nInitialBufferPos = nInitialSilence;
        float fInitialSamplePos = pNote->m_fSamplePosition;
        float fSamplePos = pNote->m_fSamplePosition;
        int nTimes = nInitialBufferPos + nAvail_bytes;
        int nInstrument = pSong->get_instrument_list()->get_pos( pNote->get_instrument() );

        // filter
        bool bUseLPF = pNote->get_instrument()->is_filter_active();
        float fResonance = pNote->get_instrument()->get_filter_resonance();
        float fCutoff = pNote->get_instrument()->get_filter_cutoff();

        float *pSample_data_L = pSample->get_data_l();
        float *pSample_data_R = pSample->get_data_r();

        float fInstrPeak_L = pNote->get_instrument()->get_peak_l(); // this value will be reset to 0 by the mixer..
        float fInstrPeak_R = pNote->get_instrument()->get_peak_r(); // this value will be reset to 0 by the mixer..

        float fADSRValue = 1.0;
        float fVal_L;
        float fVal_R;
        int nSampleFrames = pSample->get_n_frames();

        /*
         * nInstrument could be -1 if the instrument is not found in the current drumset.
         * This happens when someone is using the prelistening function of the soundlibrary.
         */

        if( nInstrument < 0 ) {
                nInstrument = 0;
        }


        for ( int nBufferPos = nInitialBufferPos; nBufferPos < nTimes; ++nBufferPos ) {
                if ( ( nNoteLength != -1 ) && ( nNoteLength <= pNote->m_fSamplePosition )  ) {
                        if ( pNote->m_adsr.release() == 0 ) {
                                retValue = 1;   // the note is ended
                        }
                }

                int nSamplePos = ( int )fSamplePos;
                float fDiff = fSamplePos - nSamplePos;
                if ( ( nSamplePos + 1 ) >= nSampleFrames ) {
                        fVal_L = linear_interpolation( pSample_data_L[ nSampleFrames ], 0, fDiff );
                        fVal_R = linear_interpolation( pSample_data_R[ nSampleFrames ], 0, fDiff );
                } else {
                        fVal_L = linear_interpolation( pSample_data_L[nSamplePos], pSample_data_L[nSamplePos + 1], fDiff );
                        fVal_R = linear_interpolation( pSample_data_R[nSamplePos], pSample_data_R[nSamplePos + 1], fDiff );
                }

                // ADSR envelope
                fADSRValue = pNote->m_adsr.get_value( fStep );
                fVal_L = fVal_L * fADSRValue;
                fVal_R = fVal_R * fADSRValue;

                // Low pass resonant filter
                if ( bUseLPF ) {
                        pNote->m_fBandPassFilterBuffer_L = fResonance * pNote->m_fBandPassFilterBuffer_L + fCutoff * ( fVal_L - pNote->m_fLowPassFilterBuffer_L );
                        pNote->m_fLowPassFilterBuffer_L += fCutoff * pNote->m_fBandPassFilterBuffer_L;
                        fVal_L = pNote->m_fLowPassFilterBuffer_L;

                        pNote->m_fBandPassFilterBuffer_R = fResonance * pNote->m_fBandPassFilterBuffer_R + fCutoff * ( fVal_R - pNote->m_fLowPassFilterBuffer_R );
                        pNote->m_fLowPassFilterBuffer_R += fCutoff * pNote->m_fBandPassFilterBuffer_R;
                        fVal_R = pNote->m_fLowPassFilterBuffer_R;
                }


                if ( __audio_output->has_track_outs() ) {
#ifdef JACK_SUPPORT
                        assert( __track_out_L[ nInstrument ] );
                        assert( __track_out_R[ nInstrument ] );
                        __track_out_L[ nInstrument ][nBufferPos] += (fVal_L * cost_track_L);
                        __track_out_R[ nInstrument ][nBufferPos] += (fVal_R * cost_track_R);
#endif
                }

                fVal_L = fVal_L * cost_L;
                fVal_R = fVal_R * cost_R;

                // update instr peak
                if ( fVal_L > fInstrPeak_L ) {
                        fInstrPeak_L = fVal_L;
                }
                if ( fVal_R > fInstrPeak_R ) {
                        fInstrPeak_R = fVal_R;
                }

                // to main mix
                __main_out_L[nBufferPos] += fVal_L;
                __main_out_R[nBufferPos] += fVal_R;

                fSamplePos += fStep;
        }
        pNote->m_fSamplePosition += nAvail_bytes * fStep;
        pNote->get_instrument()->set_peak_l( fInstrPeak_L );
        pNote->get_instrument()->set_peak_r( fInstrPeak_R );



#ifdef LADSPA_SUPPORT
        // LADSPA
        for ( unsigned nFX = 0; nFX < MAX_FX; ++nFX ) {
                LadspaFX *pFX = Effects::getInstance()->getLadspaFX( nFX );
                float fLevel = pNote->get_instrument()->get_fx_level( nFX );
                if ( ( pFX ) && ( fLevel != 0.0 ) ) {
                        fLevel = fLevel * pFX->getVolume();

                        float *pBuf_L = pFX->m_pBuffer_L;
                        float *pBuf_R = pFX->m_pBuffer_R;

//                      float fFXCost_L = cost_L * fLevel;
//                      float fFXCost_R = cost_R * fLevel;
                        float fFXCost_L = fLevel * fSendFXLevel_L;
                        float fFXCost_R = fLevel * fSendFXLevel_R;

                        int nBufferPos = nInitialBufferPos;
                        float fSamplePos = fInitialSamplePos;
                        for ( int i = 0; i < nAvail_bytes; ++i ) {
                                int nSamplePos = ( int )fSamplePos;
                                float fDiff = fSamplePos - nSamplePos;

                                if ( ( nSamplePos + 1 ) >= nSampleFrames ) {
                                        fVal_L = linear_interpolation( pSample_data_L[nSamplePos], 0, fDiff );
                                        fVal_R = linear_interpolation( pSample_data_R[nSamplePos], 0, fDiff );
                                } else {
                                        fVal_L = linear_interpolation( pSample_data_L[nSamplePos], pSample_data_L[nSamplePos + 1], fDiff );
                                        fVal_R = linear_interpolation( pSample_data_R[nSamplePos], pSample_data_R[nSamplePos + 1], fDiff );
                                }

                                pBuf_L[ nBufferPos ] += fVal_L * fFXCost_L;
                                pBuf_R[ nBufferPos ] += fVal_R * fFXCost_R;
                                fSamplePos += fStep;
                                ++nBufferPos;
                        }
                }
        }
#endif

        return retValue;
}


void Sampler::stop_playing_notes( Instrument* instrument )
{
        /*
        // send a note-off event to all notes present in the playing note queue
        for ( int i = 0; i < __playing_notes_queue.size(); ++i ) {
                Note *pNote = __playing_notes_queue[ i ];
                pNote->m_pADSR->release();
        }
        */

        if ( instrument ) { // stop all notes using this instrument
                for ( unsigned i = 0; i < __playing_notes_queue.size(); ) {
                        Note *pNote = __playing_notes_queue[ i ];
                        assert( pNote );
                        if ( pNote->get_instrument() == instrument ) {
                                delete pNote;
                                instrument->dequeue();
                                __playing_notes_queue.erase( __playing_notes_queue.begin() + i );
                        }
                        ++i;
                }
        } else { // stop all notes
                // delete all copied notes in the playing notes queue
                for ( unsigned i = 0; i < __playing_notes_queue.size(); ++i ) {
                        Note *pNote = __playing_notes_queue[i];
                        pNote->get_instrument()->dequeue();
                        delete pNote;
                }
                __playing_notes_queue.clear();
        }
}



/// Preview, uses only the first layer
void Sampler::preview_sample( Sample* sample )
{
        AudioEngine::get_instance()->lock( "Sampler::previewSample" );

        InstrumentLayer *pLayer = __preview_instrument->get_layer( 0 );

        Sample *pOldSample = pLayer->get_sample();
        pLayer->set_sample( sample );
        delete pOldSample;

        Note *previewNote = new Note( __preview_instrument, 0, 1.0, 0.5, 0.5, MAX_NOTES, 0 );

        stop_playing_notes( __preview_instrument );
        note_on( previewNote );
        __preview_instrument->enqueue();

        AudioEngine::get_instance()->unlock();
}



void Sampler::preview_instrument( Instrument* instr )
{
        Instrument * old_preview;
        AudioEngine::get_instance()->lock( "Sampler::previewInstrument" );

        stop_playing_notes( __preview_instrument );

        old_preview = __preview_instrument
        __preview_instrument = instr;

        Note *previewNote = new Note( __preview_instrument, 0, 1.0, 0.5, 0.5, MAX_NOTES, 0 );

        note_on( previewNote ); // exclusive note
        instr->enqueue();
        AudioEngine::get_instance()->unlock();
        delete old_preview;
}



void Sampler::set_audio_output( AudioOutput* audio_output )
{
        __audio_output = audio_output;
}

void Sampler::makeTrackOutputQueues( )
{
        INFOLOG( "Making Output Queues" );

#ifdef JACK_SUPPORT
        if ( __audio_output->has_track_outs() ) {
                for (int nTrack = 0; nTrack < ( ( JackOutput* )__audio_output )->getNumTracks( ); nTrack++) {
                        __track_out_L[nTrack] = ( ( JackOutput* )__audio_output )->getTrackOut_L( nTrack );
                        assert( __track_out_L[ nTrack ] );
                        __track_out_R[nTrack] = ( ( JackOutput* )__audio_output )->getTrackOut_R( nTrack );
                        assert( __track_out_R[ nTrack ] );
                }
        }
#endif // JACK_SUPPORT

}



};