stk::TapDelay Class Reference

STK non-interpolating tapped delay line class. More...

#include <TapDelay.h>

Inheritance diagram for stk::TapDelay:

Public Member Functions
	TapDelay (std::vector< unsigned long > taps=std::vector< unsigned long >(1, 0), unsigned long maxDelay=4095)
	The default constructor creates a delay-line with maximum length of 4095 samples and a single tap at delay = 0. More...
	~TapDelay ()
	Class destructor.
void	setMaximumDelay (unsigned long delay)
	Set the maximum delay-line length. More...
void	setTapDelays (std::vector< unsigned long > taps)
	Set the delay-line tap lengths. More...
std::vector< unsigned long >	getTapDelays (void) const
	Return the current delay-line length.
StkFloat	lastOut (unsigned int tap=0) const
	Return the specified tap value of the last computed frame. More...
StkFrames &	tick (StkFloat input, StkFrames &outputs)
	Input one sample to the delayline and return outputs at all tap positions. More...
StkFrames &	tick (StkFrames &frames, unsigned int channel=0)
	Take a channel of the StkFrames object as inputs to the filter and write outputs back to the same object. More...
StkFrames &	tick (StkFrames &iFrames, StkFrames &oFrames, unsigned int iChannel=0)
	Take a channel of the iFrames object as inputs to the filter and write outputs to the oFrames object. More...
unsigned int	channelsIn (void) const
	Return the number of input channels for the class.
unsigned int	channelsOut (void) const
	Return the number of output channels for the class.
virtual void	clear (void)
	Clears all internal states of the filter.
void	setGain (StkFloat gain)
	Set the filter gain. More...
StkFloat	getGain (void) const
	Return the current filter gain.
StkFloat	phaseDelay (StkFloat frequency)
	Return the filter phase delay at the specified frequency. More...
const StkFrames &	lastFrame (void) const
	Return an StkFrames reference to the last output sample frame.
void	ignoreSampleRateChange (bool ignore=true)
	A function to enable/disable the automatic updating of class data when the STK sample rate changes. More...

Static Public Member Functions
static StkFloat	sampleRate (void)
	Static method that returns the current STK sample rate.
static void	setSampleRate (StkFloat rate)
	Static method that sets the STK sample rate. More...
static void	clear_alertList ()
	Static method that frees memory from alertList_.
static std::string	rawwavePath (void)
	Static method that returns the current rawwave path.
static void	setRawwavePath (std::string path)
	Static method that sets the STK rawwave path.
static void	swap16 (unsigned char *ptr)
	Static method that byte-swaps a 16-bit data type.
static void	swap32 (unsigned char *ptr)
	Static method that byte-swaps a 32-bit data type.
static void	swap64 (unsigned char *ptr)
	Static method that byte-swaps a 64-bit data type.
static void	sleep (unsigned long milliseconds)
	Static cross-platform method to sleep for a number of milliseconds.
static bool	inRange (StkFloat value, StkFloat min, StkFloat max)
	Static method to check whether a value is within a specified range.
static void	handleError (const char *message, StkError::Type type)
	Static function for error reporting and handling using c-strings.
static void	handleError (std::string message, StkError::Type type)
	Static function for error reporting and handling using c++ strings.
static void	showWarnings (bool status)
	Toggle display of WARNING and STATUS messages.
static void	printErrors (bool status)
	Toggle display of error messages before throwing exceptions.

Static Public Attributes
static const StkFormat	STK_SINT8
static const StkFormat	STK_SINT16
static const StkFormat	STK_SINT24
static const StkFormat	STK_SINT32
static const StkFormat	STK_FLOAT32
static const StkFormat	STK_FLOAT64

Protected Member Functions
void	handleError (StkError::Type type) const
	Internal function for error reporting that assumes message in oStream_ variable.
virtual void	sampleRateChanged (StkFloat newRate, StkFloat oldRate)
	This function should be implemented in subclasses that depend on the sample rate.
void	addSampleRateAlert (Stk *ptr)
	Add class pointer to list for sample rate change notification.
void	removeSampleRateAlert (Stk *ptr)
	Remove class pointer from list for sample rate change notification.

Detailed Description

STK non-interpolating tapped delay line class.

This class implements a non-interpolating digital delay-line with an arbitrary number of output "taps". If the maximum length and tap delays are not specified during instantiation, a fixed maximum length of 4095 and a single tap delay of zero is set.

A non-interpolating delay line is typically used in fixed delay-length applications, such as for reverberation.

by Perry R. Cook and Gary P. Scavone, 1995–2019.

Constructor & Destructor Documentation

TapDelay()

stk::TapDelay::TapDelay	(	std::vector< unsigned long >	taps = std::vector< unsigned long >(1, 0),
		unsigned long	maxDelay = 4095
	)

The default constructor creates a delay-line with maximum length of 4095 samples and a single tap at delay = 0.

An StkError will be thrown if any tap delay parameter is less than zero, the maximum delay parameter is less than one, or any tap delay parameter is greater than the maxDelay value.

Member Function Documentation

setMaximumDelay()

void stk::TapDelay::setMaximumDelay

(

unsigned long

delay

)

Set the maximum delay-line length.

This method should generally only be used during initial setup of the delay line. If it is used between calls to the tick() function, without a call to clear(), a signal discontinuity will likely occur. If the current maximum length is greater than the new length, no change will be made.

setTapDelays()

void stk::TapDelay::setTapDelays

(

std::vector< unsigned long >

taps

)

Set the delay-line tap lengths.

The valid range for each tap length is from 0 to the maximum delay-line length.

lastOut()

StkFloat stk::TapDelay::lastOut ( unsigned int  tap = 0 ) const

inline

Return the specified tap value of the last computed frame.

Use the lastFrame() function to get all tap values from the last computed frame. The tap argument must be less than the number of delayline taps (the first tap is specified by 0). However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

{
#if defined(_STK_DEBUG_)
  if ( tap >= lastFrame_.size() ) {
    oStream_ << "TapDelay::lastOut(): tap argument and number of taps are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  return lastFrame_[tap];
}

tick() [1/3]

StkFrames & stk::TapDelay::tick ( StkFloat  input, StkFrames &  outputs  )

inline

Input one sample to the delayline and return outputs at all tap positions.

The StkFrames argument reference is returned. The output values are ordered according to the tap positions set using the setTapDelays() function (no sorting is performed). The StkFrames argument must contain at least as many channels as the number of taps. However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

{
#if defined(_STK_DEBUG_)
  if ( outputs.channels() < outPoint_.size() ) {
    oStream_ << "TapDelay::tick(): number of taps > channels in StkFrames argument!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  inputs_[inPoint_++] = input * gain_;
 
  // Check for end condition
  if ( inPoint_ == inputs_.size() )
    inPoint_ = 0;
 
  // Read out next values
  StkFloat *outs = &outputs[0];
  for ( unsigned int i=0; i<outPoint_.size(); i++ ) {
    *outs++ = inputs_[outPoint_[i]];
    lastFrame_[i] = *outs;
    if ( ++outPoint_[i] == inputs_.size() )
      outPoint_[i] = 0;
  }
 
  return outputs;
}

tick() [2/3]

StkFrames & stk::TapDelay::tick ( StkFrames &  frames, unsigned int  channel = 0  )

inlinevirtual

Take a channel of the StkFrames object as inputs to the filter and write outputs back to the same object.

The StkFrames argument reference is returned. The output values are ordered according to the tap positions set using the setTapDelays() function (no sorting is performed). The StkFrames argument must contain at least as many channels as the number of taps. However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

Implements stk::Filter.

{
#if defined(_STK_DEBUG_)
  if ( channel >= frames.channels() ) {
    oStream_ << "TapDelay::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
  if ( frames.channels() < outPoint_.size() ) {
    oStream_ << "TapDelay::tick(): number of taps > channels in StkFrames argument!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *iSamples = &frames[channel];
  StkFloat *oSamples = &frames[0];
  size_t j;
  unsigned int iHop = frames.channels();
  size_t oHop = frames.channels() - outPoint_.size();
  for ( unsigned long i=0; i<frames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
    inputs_[inPoint_++] = *iSamples * gain_;
    if ( inPoint_ == inputs_.size() ) inPoint_ = 0;
    for ( j=0; j<outPoint_.size(); j++ ) {
      *oSamples++ = inputs_[outPoint_[j]];
      if ( ++outPoint_[j] == inputs_.size() ) outPoint_[j] = 0;
    }
  }
 
  oSamples -= frames.channels();
  for ( j=0; j<outPoint_.size(); j++ ) lastFrame_[j] = *oSamples++;
  return frames;
}

tick() [3/3]

StkFrames & stk::TapDelay::tick ( StkFrames &  iFrames, StkFrames &  oFrames, unsigned int  iChannel = 0  )

inline

Take a channel of the iFrames object as inputs to the filter and write outputs to the oFrames object.

The iFrames object reference is returned. The output values are ordered according to the tap positions set using the setTapDelays() function (no sorting is performed). The iChannel argument must be less than the number of channels in the iFrames argument (the first channel is specified by 0). The oFrames argument must contain at least as many channels as the number of taps. However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

{
#if defined(_STK_DEBUG_)
  if ( iChannel >= iFrames.channels() ) {
    oStream_ << "TapDelay::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
  if ( oFrames.channels() < outPoint_.size() ) {
    oStream_ << "TapDelay::tick(): number of taps > channels in output StkFrames argument!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *iSamples = &iFrames[iChannel];
  StkFloat *oSamples = &oFrames[0];
  size_t j;
  unsigned int iHop = iFrames.channels();
  size_t oHop = oFrames.channels() - outPoint_.size();
  for ( unsigned long i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
    inputs_[inPoint_++] = *iSamples * gain_;
    if ( inPoint_ == inputs_.size() ) inPoint_ = 0;
    for ( j=0; j<outPoint_.size(); j++ ) {
      *oSamples++ = inputs_[outPoint_[j]];
      if ( ++outPoint_[j] == inputs_.size() ) outPoint_[j] = 0;
    }
  }
 
  oSamples -= oFrames.channels();
  for ( j=0; j<outPoint_.size(); j++ ) lastFrame_[j] = *oSamples++;
  return iFrames;
}

setGain()

void stk::Filter::setGain ( StkFloat  gain )

inlineinherited

Set the filter gain.

The gain is applied at the filter input and does not affect the coefficient values. The default gain value is 1.0.

{ gain_ = gain; };

phaseDelay()

StkFloat stk::Filter::phaseDelay ( StkFloat  frequency )

inlineinherited

Return the filter phase delay at the specified frequency.

Note that the phase delay calculation accounts for the filter gain. The frequency value should be greater than 0.0 and less than or equal to one-half the sample rate.

{
  if ( frequency <= 0.0 || frequency > 0.5 * Stk::sampleRate() ) {
    oStream_ << "Filter::phaseDelay: argument (" << frequency << ") is out of range!";
    handleError( StkError::WARNING ); return 0.0;
  }
 
  StkFloat omegaT = 2 * STK_PI * frequency / Stk::sampleRate();
  StkFloat real = 0.0, imag = 0.0;
  for ( unsigned int i=0; i<b_.size(); i++ ) {
    real += b_[i] * std::cos( i * omegaT );
    imag -= b_[i] * std::sin( i * omegaT );
  }
  real *= gain_;
  imag *= gain_;
 
  StkFloat phase = atan2( imag, real );
 
  real = 0.0, imag = 0.0;
  for ( unsigned int i=0; i<a_.size(); i++ ) {
    real += a_[i] * std::cos( i * omegaT );
    imag -= a_[i] * std::sin( i * omegaT );
  }
 
  phase -= std::atan2( imag, real );
  phase = std::fmod( -phase, 2 * STK_PI );
  return phase / omegaT;
}

setSampleRate()

static void stk::Stk::setSampleRate ( StkFloat  rate )

staticinherited

Static method that sets the STK sample rate.

The sample rate set using this method is queried by all STK classes that depend on its value. It is initialized to the default SRATE set in Stk.h. Many STK classes use the sample rate during instantiation. Therefore, if you wish to use a rate that is different from the default rate, it is imperative that it be set BEFORE STK objects are instantiated. A few classes that make use of the global STK sample rate are automatically notified when the rate changes so that internal class data can be appropriately updated. However, this has not been fully implemented. Specifically, classes that appropriately update their own data when either a setFrequency() or noteOn() function is called do not currently receive the automatic notification of rate change. If the user wants a specific class instance to ignore such notifications, perhaps in a multi-rate context, the function Stk::ignoreSampleRateChange() should be called.

ignoreSampleRateChange()

void stk::Stk::ignoreSampleRateChange ( bool  ignore = true )

inlineinherited

A function to enable/disable the automatic updating of class data when the STK sample rate changes.

This function allows the user to enable or disable class data updates in response to global sample rate changes on a class by class basis.

{ ignoreSampleRateChange_ = ignore; };

Member Data Documentation

STK_SINT8

const StkFormat stk::Stk::STK_SINT8

staticinherited

-128 to +127

STK_SINT16

const StkFormat stk::Stk::STK_SINT16

staticinherited

-32768 to +32767

STK_SINT24

const StkFormat stk::Stk::STK_SINT24

staticinherited

Lower 3 bytes of 32-bit signed integer.

STK_SINT32

const StkFormat stk::Stk::STK_SINT32

staticinherited

-2147483648 to +2147483647.

STK_FLOAT32

const StkFormat stk::Stk::STK_FLOAT32

staticinherited

Normalized between plus/minus 1.0.

STK_FLOAT64

const StkFormat stk::Stk::STK_FLOAT64

staticinherited

Normalized between plus/minus 1.0.

---

The documentation for this class was generated from the following file:

• TapDelay.h