C++ Partial::begin方法代码示例

// ---------------------------------------------------------------------------
//	channelize (one Partial)
// ---------------------------------------------------------------------------
//!	Label a Partial with the number of the frequency channel corresponding to
//!	the average frequency over all the Partial's Breakpoints.
//!	
//!	\param partial is the Partial to label.
//
void
Channelizer::channelize( Partial & partial ) const
{
	debugger << "channelizing Partial with " << partial.numBreakpoints() << " Breakpoints" << endl;
			
	//	compute an amplitude-weighted average channel
	//	label for each Partial:
	double ampsum = 0.;
	double weightedlabel = 0.;
	Partial::const_iterator bp;
	for ( bp = partial.begin(); bp != partial.end(); ++bp )
	{
		//	use sinusoidal amplitude:
		double a = bp.breakpoint().amplitude() * std::sqrt( 1. - bp.breakpoint().bandwidth() );
		
		//  This used to be an amplitude-weighted avg, but for many sounds, 
		//  particularly those for which the weighted avg would be very
		//  different from the simple avg, the amplitude-weighted avg
		//  emphasized the part of the sound in which the frequency estimates
		//  are least reliable (e.g. a piano tone). The unweighted 
		//  average should give more intuitive results in most cases.
				
		double f = bp.breakpoint().frequency();
		double t = bp.time();
		
		double refFreq = _refChannelFreq->valueAt( t ) / _refChannelLabel;
		// weightedlabel += a * (f / refFreq);
		weightedlabel += a * giveMeN( f, refFreq, _stretchFactor );
		ampsum += a;
	}
	
	int label;
	if ( ampsum > 0. )	
	// if ( 0 < partial.numBreakpoints() )
	{
		label = (int)((weightedlabel / ampsum) + 0.5);
	}
	else	//	this should never happen, but just in case:
	{
		label = 0;
	}
	Assert( label >= 0 );
			
	//	assign label, and remember it, but
	//	only if it is a valid (positive) 
	//	distillation label:
	partial.setLabel( label );

}

// ---------------------------------------------------------------------------
//	channelize (one Partial)
// ---------------------------------------------------------------------------
//!	Label a Partial with the number of the frequency channel corresponding to
//!	the average frequency over all the Partial's Breakpoints.
//!	
//!	\param partial is the Partial to label.
//
void
Channelizer::channelize( Partial & partial ) const
{
    using std::pow;

	debugger << "channelizing Partial with " << partial.numBreakpoints() << " Breakpoints" << endl;
			
	//	compute an amplitude-weighted average channel
	//	label for each Partial:
	//double ampsum = 0.;
	double weightedlabel = 0.;
	Partial::const_iterator bp;
	for ( bp = partial.begin(); bp != partial.end(); ++bp )
	{
				
		double f = bp.breakpoint().frequency();
		double t = bp.time();
		
        double weight = 1;
        if ( 0 != _ampWeighting )
        {
            //  This used to be an amplitude-weighted avg, but for many sounds, 
            //  particularly those for which the weighted avg would be very
            //  different from the simple avg, the amplitude-weighted avg
            //  emphasized the part of the sound in which the frequency estimates
            //  are least reliable (e.g. a piano tone). The unweighted 
            //  average should give more intuitive results in most cases.

            //	use sinusoidal amplitude:
            double a = bp.breakpoint().amplitude() * std::sqrt( 1. - bp.breakpoint().bandwidth() );                
            weight = pow( a, _ampWeighting );
        }
        
        weightedlabel += weight * computeFractionalChannelNumber( t, f );
	}
	
	int label = 0;
	if ( 0 < partial.numBreakpoints() ) //  should always be the case
	{        
		label = (int)((weightedlabel / partial.numBreakpoints()) + 0.5);
	}
	Assert( label >= 0 );
			
	//	assign label, and remember it, but
	//	only if it is a valid (positive) 
	//	distillation label:
	partial.setLabel( label );

}

// ---------------------------------------------------------------------------
//	TimeShifter function call operator
// ---------------------------------------------------------------------------
//	Shift the time of all the Breakpoints in a Partial by a constant amount.
//
void 
TimeShifter::operator()( Partial & p ) const
{
	//	Since the Breakpoint times are immutable, the only way to 
	//	shift the Partial in time is to construct a new Partial and
	//	assign it to the argument p.
	Partial result;
	result.setLabel( p.label() );
	
	for ( Partial::iterator pos = p.begin(); pos != p.end(); ++pos ) 
	{		
		result.insert( pos.time() + offset, pos.breakpoint() );
	}	
	p = result;
}

// ---------------------------------------------------------------------------
//	avgFrequency
// ---------------------------------------------------------------------------
//! Return the average frequency over all Breakpoints in this Partial.
//! Return zero if the Partial has no Breakpoints.
//!  
//! \param  p is the Partial to evaluate
//! \return the average frequency (Hz) of Breakpoints in the Partial p
//
double avgFrequency( const Partial & p )
{
    double avg = 0;
    for ( Partial::const_iterator it = p.begin();
          it != p.end();
          ++it )
    {
        avg += it->frequency();
    }
    
    if ( avg != 0 )
    {
        avg /= p.numBreakpoints();
    }
    
    return avg;
}

// ---------------------------------------------------------------------------
//	timeOfPeakEnergy (static helper function)
// ---------------------------------------------------------------------------
//	Return the time at which the given Partial attains its
//	maximum sinusoidal energy.
//
static double timeOfPeakEnergy( const Partial & p )
{
	Partial::const_iterator partialIter = p.begin();
	double maxAmp = 
		partialIter->amplitude() * std::sqrt( 1. - partialIter->bandwidth() );
	double time = partialIter.time();
	
	for ( ++partialIter; partialIter != p.end(); ++partialIter ) 
	{
		double a = partialIter->amplitude() * 
					std::sqrt( 1. - partialIter->bandwidth() );
		if ( a > maxAmp ) 
		{
			maxAmp = a;
			time = partialIter.time();
		}
	}			
	
	return time;
}

Iter
find_overlapping( Partial & p, double minGapTime, Iter start, Iter end)
{
	for ( Iter it = start; it != end; ++it ) 
	{
		//	skip if other partial is already sifted out.
		if ( (*it)->label() == 0 )
			continue;
		
		//	skip the source Partial:
		//	(identity test: compare addresses)
		//	(this is a sanity check, should not happen since
		//	src should be at position end)
		Assert( (*it) != &p );

		//  test for overlap:
		if ( p.startTime() < (*it)->endTime() + minGapTime &&
			 p.endTime() + minGapTime > (*it)->startTime() )
		{
			//  Does the overlapping Partial have longer duration?
			//	(this should never be true, since the Partials
			//	are sorted by duration)
			Assert( p.duration() <= (*it)->duration() );
			
#if Debug_Loris
			debugger << "Partial starting " << p.startTime() << ", " 
					 << p.begin().breakpoint().frequency() << " ending " 
					 << p.endTime()  << ", " << (--p.end()).breakpoint().frequency() 
					 << " zapped by overlapping Partial starting " 
					 << (*it)->startTime() << ", " << (*it)->begin().breakpoint().frequency()
					 << " ending " << (*it)->endTime() << ", " 
					 << (--(*it)->end()).breakpoint().frequency()  << endl;
#endif
			return it;
		}
	}
	
	//	no overlapping Partial found:
	return end;
}

// ---------------------------------------------------------------------------
//	weightedAvgFrequency
// ---------------------------------------------------------------------------
//! Return the average frequency over all Breakpoints in this Partial, 
//! weighted by the Breakpoint amplitudes.
//! Return zero if the Partial has no Breakpoints.
//!  
//! \param  p is the Partial to evaluate
//! \return the average frequency (Hz) of Breakpoints in the Partial p
//
double weightedAvgFrequency( const Partial & p )
{
    double avg = 0;
    double ampsum = 0;
    for ( Partial::const_iterator it = p.begin();
          it != p.end();
          ++it )
    {
        avg += it->amplitude() * it->frequency();
        ampsum += it->amplitude();
    }
    
    if ( avg != 0 && ampsum != 0 )
    {
        avg /= ampsum;
    }
    else
    {
        avg = 0;
    }
    
    return avg;
}

// ----------- test_distill_overlapping3 -----------
//
static void test_distill_overlapping3( void )
{
    std::cout << "\t--- testing distill on three "
                 "temporally-overlapping Partials... ---\n\n";

    //  Fabricate three Partials, overlapping temporally, give
    //  them the same label, and distill them.
    Partial p1;
    p1.insert( 0, Breakpoint( 100, 0.4, 0, 0 ) );
    p1.insert( 0.28, Breakpoint( 100, 0.4, 0, .1 ) );
    p1.setLabel( 123 );
    
    Partial p2;
    p2.insert( 0.2, Breakpoint( 200, 0.3, 0.2, 0 ) );
    p2.insert( 0.29, Breakpoint( 200, 0.3, 0.2, .1 ) );
    p2.insert( 0.35, Breakpoint( 200, 0.3, 0.2, .1 ) );
    p2.setLabel( 123 );

    Partial p3;
    p3.insert( 0.32, Breakpoint( 300, 0.3, 0, 0 ) );
    p3.insert( 0.4, Breakpoint( 310, 0.3, 0.2, .1 ) );
    p3.insert( 0.7, Breakpoint( 310, 0.3, 0.2, .1 ) );
    p3.setLabel( 123 );

    PartialList l;
    l.push_back( p3 );
    l.push_back( p1 );
    l.push_back( p2 );

    const double fade = .008; // 8 ms
    Distiller d( fade );
    d.distill( l );
    
    //  Fabricate the Partial that the distillation should 
    //  produce.
    Partial compare;
    
    //  first Breakpoint from p1
    compare.insert( 0, Breakpoint( 100, 0.4, 0, 0 ) );

    //  null Breakpoint at 0+fade
    double t = 0 + fade;
    compare.insert( t, Breakpoint( p1.frequencyAt(t), 0, 
                                   p1.bandwidthAt(t), p1.phaseAt(t) ) );
    //  interpolated Breakpoint at .18 (.2 - 2*fade)
    //double t = 0.2 - (2*fade);
    //compare.insert( t, p1.parametersAt( t ) );

    //  null Breakpoint at .19 (.2-fade)
    //  bandwidth introduced in the overlap region:
    //  (0.4^2 + 0.2*0.3^2) / (0.3^2 + 0.4^2)) = 0.712
    //  amp = sqrt(0.3^2 + 0.4^2) = .5
    //  no, actually zero-amplitude Breakpoints are
    //  introduced with zero bandwidth.
    t = 0.2 - fade;
    compare.insert( t, Breakpoint( p2.frequencyAt(t), 0, 
                                   0, // 0.712, 
                                   p2.phaseAt(t) ) );
                                   
    //  first Breakpoint from p2:
    compare.insert( 0.2, Breakpoint( 200, 0.5, 0.712, 0 ) );
                                   
    //  second Breakpoint from p2:
    compare.insert( 0.29, Breakpoint( 200, 0.3, 0.2, 0.1 ) );

    //  null Breakpoint at .29 + fade
    t = 0.29 + fade;
    compare.insert( t, Breakpoint( p2.frequencyAt(t), 0, 
                                   0, // p2.bandwidthAt(t), 
                                   p2.phaseAt(t) ) );

    //  null Breakpoint at .31 (.32-fade)
    t = 0.32 - fade;
    compare.insert( t, Breakpoint( p3.frequencyAt(t), 0, 
                                   0, p3.phaseAt(t) ) );

    //  first Breakpoint from p3 (with bandwidth):
    compare.insert( 0.32, Breakpoint( 300, std::sqrt(0.18), 0.5, 0 ) );
                                   
    //  second Breakpoint from p3:
    compare.insert( 0.4, Breakpoint( 310, 0.3, 0.2, .1 ) );
                                   
    //  third Breakpoint from p3:
    compare.insert( 0.7, Breakpoint( 310, 0.3, 0.2, .1 ) );
    compare.setLabel( 123 );

    //  compare Partials (distilled Partials
    //  should be in label order):
    TEST_VALUE( l.size(), 1 );
    TEST_VALUE( l.begin()->numBreakpoints(), compare.numBreakpoints() );
    
    Partial::iterator distit = l.begin()->begin();
    Partial::iterator compareit = compare.begin();
    while ( compareit != compare.end() )
    {
        SAME_PARAM_VALUES( distit.time(), compareit.time() );
        SAME_PARAM_VALUES( distit->frequency(), compareit->frequency() );
        SAME_PARAM_VALUES( distit->amplitude(), compareit->amplitude() );
//.........这里部分代码省略.........

// ----------- test_distill_nonoverlapping -----------
//
static void test_distill_nonoverlapping( void )
{
    std::cout << "\t--- testing distill on "
                 "non-overlapping Partials... ---\n\n";
                 
    //  Fabricate three non-overlapping Partials, give
    //  them all the same label, and distill them. Also
    //  add a fourth Partial with a different label, verify
    //  that it remains unaffacted.
    Partial p1;
    p1.insert( 0, Breakpoint( 100, 0.1, 0, 0 ) );
    p1.insert( .1, Breakpoint( 110, 0.2, 0.2, .1 ) );
    p1.setLabel( 123 );
    
    Partial p2;
    p2.insert( 0.2, Breakpoint( 200, 0.1, 0, 0 ) );
    p2.insert( 0.3, Breakpoint( 210, 0.2, 0.2, .1 ) );
    p2.setLabel( 123 );
    
    Partial p3;
    p3.insert( 0.4, Breakpoint( 300, 0.1, 0, 0 ) );
    p3.insert( 0.5, Breakpoint( 310, 0.2, 0.2, .1 ) );
    p3.setLabel( 123 );
    
    Partial p4;
    p4.insert( 0, Breakpoint( 400, 0.1, 0, 0 ) );
    p4.insert( 0.5, Breakpoint( 410, 0.2, 0.2, .1 ) );
    p4.setLabel( 4 );
    
    PartialList l;
    l.push_back( p1 );
    l.push_back( p3 );
    l.push_back( p4 );
    l.push_back( p2 );
    
    const double fade = .01; // 10 ms
    Distiller d( fade );
    d.distill( l );
    
    //  Fabricate the Partial that the distillation should 
    //  produce.
    Partial compare;
    compare.insert( 0, Breakpoint( 100, 0.1, 0, 0 ) );
    compare.insert( 0.1, Breakpoint( 110, 0.2, 0.2, .1 ) );
    double t = 0.1 + fade;
    compare.insert( t, Breakpoint( p1.frequencyAt(t), 0, 
                                   0, // p1.bandwidthAt(t), 
                                   p1.phaseAt(t) ) );
    t = 0.2 - fade;
    compare.insert( t, Breakpoint( p2.frequencyAt(t), 0, 
                                   0, // p2.bandwidthAt(t), 
                                   p2.phaseAt(t) ) );
    compare.insert( 0.2, Breakpoint( 200, 0.1, 0, 0 ) );
    compare.insert( 0.3, Breakpoint( 210, 0.2, 0.2, .1 ) );
    t = 0.3 + fade;
    compare.insert( t, Breakpoint( p2.frequencyAt(t), 0, 
                                   0, // p2.bandwidthAt(t), 
                                   p2.phaseAt(t) ) );
    t = 0.4 - fade;
    compare.insert( t, Breakpoint( p3.frequencyAt(t), 0, 
                                   0, // p3.bandwidthAt(t), 
                                   p3.phaseAt(t) ) );    
    compare.insert( 0.4, Breakpoint( 300, 0.1, 0, 0 ) );
    compare.insert( 0.5, Breakpoint( 310, 0.2, 0.2, .1 ) );
    compare.setLabel( 123 );
    
    //  compare Partials (distilled Partials
    //  should be in label order):
    TEST( l.size() == 2 );
    PartialList::iterator it = l.begin();
    TEST( it->label() == p4.label() );
    TEST( it->numBreakpoints() == p4.numBreakpoints() );
    ++it;
    
    for ( Partial::iterator distit = it->begin(); distit != it->end(); ++distit )
    {
        cout << distit.time() << " " << distit.breakpoint().frequency() << endl;
    }
    
    TEST( it->numBreakpoints() == compare.numBreakpoints() );
    
    Partial::iterator distit = it->begin();
    Partial::iterator compareit = compare.begin();
    while ( compareit != compare.end() )
    {
        SAME_PARAM_VALUES( distit.time(), compareit.time() );
        SAME_PARAM_VALUES( distit->frequency(), compareit->frequency() );
        SAME_PARAM_VALUES( distit->amplitude(), compareit->amplitude() );
        SAME_PARAM_VALUES( distit->bandwidth(), compareit->bandwidth() );
        SAME_PARAM_VALUES( distit->phase(), compareit->phase() );
        
        ++compareit;
        ++distit;
    }
}

// ---------------------------------------------------------------------------
//	distillOne
// ---------------------------------------------------------------------------
//	Distill a list of Partials having a common label
// 	into a single Partial with that label, and append it
//  to the distilled collection. If an empty list of Partials
//  is passed, then an empty Partial having the specified
//  label is appended.
//
void Distiller::distillOne( PartialList & partials, Partial::label_type label,
                            PartialList & distilled )
{
	debugger << "Distiller found " << partials.size() 
			 << " Partials labeled " << label << endl;

	Partial newp;
    newp.setLabel( label );

    if ( partials.size() == 1 )
    {
        //  trivial if there is only one partial to distill
        newp = partials.front();
    }
	else if ( partials.size() > 0 )  //  it will be an empty Partial otherwise
    {	
    	//	sort Partials by duration, longer
    	//	Partials will be prefered:
    	partials.sort( distillSorter );
    	
    	// keep the longest Partial:
    	PartialList::iterator it = partials.begin();
    	newp = *it;
    	fadeInAndOut( newp, _fadeTime );
        	
    	//	Iterate over remaining Partials:
    	for ( ++it; it != partials.end(); ++it )
    	{            
            fadeInAndOut( *it, _fadeTime );
            
    		std::pair< Partial::iterator, Partial::iterator > range = 
    			findContribution( *it, newp, _fadeTime, _gapTime );
    		Partial::iterator cb = range.first, ce = range.second;

            //  There can only be one contributing regions because
            //  (and only because) the partials are sorted by length
            //  first!
    		
    		//	merge Breakpoints into the new Partial, if
    		//	there are any that contribute, otherwise
    		//	just absorb the current Partial as noise:
    		if ( cb != ce )
    		{
    			//	absorb the non-contributing part:
    			if ( ce != it->end() )
    			{
    				Partial absorbMe( --Partial::iterator(ce), it->end() );
    				    //  shouldn't this just be ce?
    				newp.absorb( absorbMe );
    			
                    //	There cannot be a non-contributing part
                    //	at the beginning of the Partial too, because
                    //  we always retain the beginning of the Partial.
                    //  If findContribution were changed, then 
                    //  we might also want to absorb the beginning.
                    //
    				// Partial absorbMeToo( it->begin(), cb );
    				// newp.absorb( absorbMeToo );
    			}

    			// merge the contributing part:
    			merge( cb, ce, newp, _fadeTime, _gapTime );
    		}
    		else
    		{
    			//	no contribution, absorb the whole thing:
    			newp.absorb( *it );
    		}		
    	}
    }	

    //  take the null Breakpoints off the ends
    //  should check whether this is appropriate?
    if ( 0 == newp.begin().breakpoint().amplitude() )
    {
        newp.erase( newp.begin() );
    }
    
    Partial::iterator lastBpPos = --(Partial::iterator(newp.end()));
    if ( 0 == lastBpPos.breakpoint().amplitude() )
    {
        newp.erase( lastBpPos );
    }
    
    //  insert the new Partial in the distilled collection 
    //  in label order:
    distilled.insert( std::lower_bound( distilled.begin(), distilled.end(), 
                                        newp, 
                                        PartialUtils::compareLabelLess() ),
                      newp );
}

// ---------------------------------------------------------------------------
//	merge	(STATIC)
// ---------------------------------------------------------------------------
//	Merge the Breakpoints in the specified iterator range into the
//	distilled Partial. The beginning of the range may overlap, and 
//	will replace, some non-zero-amplitude portion of the distilled
//	Partial. Assume that there is no such overlap at the end of the 
//	range (could check), because findContribution only leaves overlap
//  at the beginning of the range.
//
static void merge( Partial::const_iterator beg, 
				   Partial::const_iterator end, 
				   Partial & destPartial, double fadeTime, 
				   double gapTime = 0. )
{	
	//	absorb energy in distilled Partial that overlaps the
	//	range to merge:
	Partial toMerge( beg, end );
	toMerge.absorb( destPartial );  
    fadeInAndOut( toMerge, fadeTime );

		
    //  find the first Breakpoint in destPartial that is after the
    //  range of merged Breakpoints, plus the required gap:
	Partial::iterator removeEnd = destPartial.findAfter( toMerge.endTime() + gapTime );
    
    //  if this Breakpoint has non-zero amplitude, need to leave time
    //  for a fade in:
	while ( removeEnd != destPartial.end() &&
            removeEnd.breakpoint().amplitude() != 0 &&
            removeEnd.time() < toMerge.endTime() + gapTime + fadeTime )
    {
        ++removeEnd;
    }   
    
	//	find the first Breakpoint in the destination Partial that needs
    //  to be removed because it is in the overlap region:
	Partial::iterator removeBegin = destPartial.findAfter( toMerge.startTime() - gapTime );
        
    //  if beforeMerge has non-zero amplitude, need to leave time
    //  for a fade out:
    if ( removeBegin != destPartial.begin() )
	{
        Partial::iterator beforeMerge = --Partial::iterator(removeBegin);
        
        while ( removeBegin != destPartial.begin() &&
                beforeMerge.breakpoint().amplitude() != 0 &&
                beforeMerge.time() > toMerge.startTime() - gapTime - fadeTime )
        {
            --removeBegin;
            if ( beforeMerge != destPartial.begin() )
            {
                --beforeMerge;
            }
        }   
        
	}
	
	//	remove the Breakpoints in the merge range from destPartial:
    double rbt = (removeBegin != destPartial.end())?(removeBegin.time()):(destPartial.endTime());
    double ret = (removeEnd != destPartial.end())?(removeEnd.time()):(destPartial.endTime());
    Assert( rbt <= ret );
	destPartial.erase( removeBegin, removeEnd );

    //  how about doing the fades here instead?
    //  fade in if necessary:
	if ( removeEnd != destPartial.end() &&
         removeEnd.breakpoint().amplitude() != 0 )
	{
        Assert( removeEnd.time() - fadeTime > toMerge.endTime() );

        //	update removeEnd so that we don't remove this 
        //	null we are inserting:
        destPartial.insert( 
            removeEnd.time() - fadeTime, 
            BreakpointUtils::makeNullBefore( removeEnd.breakpoint(), fadeTime ) );
	}

    if ( removeEnd != destPartial.begin() )
    {
        Partial::iterator beforeMerge = --Partial::iterator(removeEnd);
        if ( beforeMerge.breakpoint().amplitude() > 0 )
        {
            Assert( beforeMerge.time() + fadeTime < toMerge.startTime() );
            
            destPartial.insert( 
                beforeMerge.time() + fadeTime, 
                BreakpointUtils::makeNullAfter( beforeMerge.breakpoint(), fadeTime ) );
        }
    }		
    
    //	insert the Breakpoints in the range:
	for ( Partial::const_iterator insert = toMerge.begin(); insert != toMerge.end(); ++insert )
	{
		destPartial.insert( insert.time(), insert.breakpoint() );
	}
}

// ---------------------------------------------------------------------------
//  synthesize
// ---------------------------------------------------------------------------
//! Synthesize a bandwidth-enhanced sinusoidal Partial. Zero-amplitude
//! Breakpoints are inserted at either end of the Partial to reduce
//! turn-on and turn-off artifacts, as described above. The synthesizer
//! will resize the buffer as necessary to accommodate all the samples,
//! including the fade out. Previous contents of the buffer are not
//! overwritten. Partials with start times earlier than the Partial fade
//! time will have shorter onset fades. Partials are not rendered at
//! frequencies above the half-sample rate. 
//!
//! \param  p The Partial to synthesize.
//! \return Nothing.
//! \pre    The partial must have non-negative start time.
//! \post   This Synthesizer's sample buffer (vector) has been 
//!         resized to accommodate the entire duration of the 
//!         Partial, p, including fade out at the end.
//! \throw  InvalidPartial if the Partial has negative start time.
//  
void
Synthesizer::synthesize( Partial p ) 
{
    if ( p.numBreakpoints() == 0 )
    {
        debugger << "Synthesizer ignoring a partial that contains no Breakpoints" << endl;
        return;
    }
    
    if ( p.startTime() < 0 )
    {
        Throw( InvalidPartial, "Tried to synthesize a Partial having start time less than 0." );
    }

    debugger << "synthesizing Partial from " << p.startTime() * m_srateHz 
             << " to " << p.endTime() * m_srateHz << " starting phase "
             << p.initialPhase() << " starting frequency " 
             << p.first().frequency() << endl;
             
    //  better to compute this only once:
    const double OneOverSrate = 1. / m_srateHz;
    
             
    //  use a Resampler to quantize the Breakpoint times and 
    //  correct the phases:
    Resampler quantizer( OneOverSrate );
    quantizer.setPhaseCorrect( true );
    quantizer.quantize( p );
    

    //  resize the sample buffer if necessary:
    typedef unsigned long index_type;
    index_type endSamp = index_type( ( p.endTime() + m_fadeTimeSec ) * m_srateHz );
    if ( endSamp+1 > m_sampleBuffer->size() )
    {
        //  pad by one sample:
        m_sampleBuffer->resize( endSamp+1 );
    }
    
    //  compute the starting time for synthesis of this Partial,
    //  m_fadeTimeSec before the Partial's startTime, but not before 0:
    double itime = ( m_fadeTimeSec < p.startTime() ) ? ( p.startTime() - m_fadeTimeSec ) : 0.;
    index_type currentSamp = index_type( (itime * m_srateHz) + 0.5 );   //  cheap rounding
    
    //  reset the oscillator:
    //  all that really needs to happen here is setting the frequency
    //  correctly, the phase will be reset again in the loop over 
    //  Breakpoints below, and the amp and bw can start at 0.
    m_osc.resetEnvelopes( BreakpointUtils::makeNullBefore( p.first(), p.startTime() - itime ), m_srateHz );

    //  cache the previous frequency (in Hz) so that it
    //  can be used to reset the phase when necessary
    //  in the sample computation loop below (this saves
    //  having to recompute from the oscillator's radian
    //  frequency):
    double prevFrequency = p.first().frequency();   
    
    //  synthesize linear-frequency segments until 
    //  there aren't any more Breakpoints to make segments:
    double * bufferBegin = &( m_sampleBuffer->front() );
    for ( Partial::const_iterator it = p.begin(); it != p.end(); ++it )
    {
        index_type tgtSamp = index_type( (it.time() * m_srateHz) + 0.5 );   //  cheap rounding
        Assert( tgtSamp >= currentSamp );
        
        //  if the current oscillator amplitude is
        //  zero, and the target Breakpoint amplitude
        //  is not, reset the oscillator phase so that
        //  it matches exactly the target Breakpoint 
        //  phase at tgtSamp:
        if ( m_osc.amplitude() == 0. )
        {
            //  recompute the phase so that it is correct
            //  at the target Breakpoint (need to do this
            //  because the null Breakpoint phase was computed
            //  from an interval in seconds, not samples, so
            //  it might be inaccurate):
            //
            //  double favg = 0.5 * ( prevFrequency + it.breakpoint().frequency() );
            //  double dphase = 2 * Pi * favg * ( tgtSamp - currentSamp ) / m_srateHz;
//.........这里部分代码省略.........

// ---------------------------------------------------------------------------
//	dilate
// ---------------------------------------------------------------------------
//!	Replace the Partial envelope with a new envelope having the
//!	same Breakpoints at times computed to align temporal features
//!	in the sorted sequence of initial time points with their 
//!	counterparts the sorted sequence of target time points.
//!
//!	Depending on the specification of initial and target time 
//!	points, the dilated Partial may have Breakpoints at times
//!	less than 0, even if the original Partial did not.
//!
//!	It is possible to have duplicate time points in either sequence.
//!	Duplicate initial time points result in very localized stretching.
//!	Duplicate target time points result in very localized compression.
//!
//!	If all initial time points are greater than 0, then an implicit
//!	time point at 0 is assumed in both initial and target sequences, 
//!	so the onset of a sound can be stretched without explcitly specifying a 
//!	zero point in each vector. (This seems most intuitive, and only looks
//!	like an inconsistency if clients are using negative time points in 
//!	their Dilator, or Partials having Breakpoints before time 0, both 
//!	of which are probably unusual circumstances.)
//!
//!	\param p is the Partial to dilate.
//	
void
Dilator::dilate( Partial & p ) const
{
	debugger << "dilating Partial having " << p.numBreakpoints() 
			 << " Breakpoints" << endl;

	//	sanity check:
	Assert( _initial.size() == _target.size() );
	
	//	don't dilate if there's no time points, or no Breakpoints:
	if ( 0 == _initial.size() ||
	     0 == p.numBreakpoints() )
	{
		return;
    }
    
	//	create the new Partial:
	Partial newp;
	newp.setLabel( p.label() );
	
	//	timepoint index:
	int idx = 0;
	for ( Partial::const_iterator iter = p.begin(); iter != p.end(); ++iter )
	{
		//	find the first initial time point later 
		//	than the currentTime:
		double currentTime = iter.time();
        idx = std::distance( _initial.begin(), 
                             std::lower_bound( _initial.begin(), _initial.end(), currentTime ) );
        Assert( idx == _initial.size() || currentTime <= _initial[idx] );
        
		//	compute a new time for the Breakpoint at pIter:
		double newtime = 0;
		if ( idx == 0 ) 
		{
			//	all time points in _initial are later than 
			//	the currentTime; stretch if no zero time 
			//	point has been specified, otherwise, shift:
			if ( _initial[idx] != 0. )
				newtime = currentTime * _target[idx] / _initial[idx];
			else
				newtime = _target[idx] + (currentTime - _initial[idx]);
		}
		else if ( idx == _initial.size() ) 
		{
			//	all time points in _initial are earlier than 
			//	the currentTime; shift:
			//
			//	note: size is already known to be > 0, so
			//	idx-1 is safe
			newtime = _target[idx-1] + (currentTime - _initial[idx-1]);
		}
		else 
		{
			//	currentTime is between the time points at idx and
			//	idx-1 in _initial; shift and stretch: 
			//
			//	note: size is already known to be > 0, so
			//	idx-1 is safe
			Assert( _initial[idx-1] < _initial[idx] );	//	currentTime can't wind up 
														//	between two equal times
			
			double stretch = (_target[idx]	- _target[idx-1]) / (_initial[idx] - _initial[idx-1]);			
			newtime = _target[idx-1] + ((currentTime - _initial[idx-1]) * stretch);
		}
		
		//	add a Breakpoint at the computed time:
		newp.insert( newtime, iter.breakpoint() );
	}
	
	//	new Breakpoints need to be added to the Partial at times corresponding
	//	to all target time points that are after the first Breakpoint and
	//	before the last, otherwise, Partials may be briefly out of tune with
	//	each other, since our Breakpoints are non-uniformly distributed in time:
//.........这里部分代码省略.........