stk::Guitar Class Reference

STK guitar model class. More...

#include <Guitar.h>

Inheritance diagram for stk::Guitar:

Public Member Functions
	Guitar (unsigned int nStrings=6, std::string bodyfile="")
	Class constructor, specifying an arbitrary number of strings (default = 6).
void	clear (void)
	Reset and clear all internal state.
void	setBodyFile (std::string bodyfile="")
	Set the string excitation, using either a soundfile or computed noise. More...
void	setPluckPosition (StkFloat position, int string=-1)
	Set the pluck position for one or all strings. More...
void	setLoopGain (StkFloat gain, int string=-1)
	Set the loop gain for one or all strings. More...
void	setFrequency (StkFloat frequency, unsigned int string=0)
	Set instrument parameters for a particular frequency.
void	noteOn (StkFloat frequency, StkFloat amplitude, unsigned int string=0)
	Start a note with the given frequency and amplitude. More...
void	noteOff (StkFloat amplitude, unsigned int string=0)
	Stop a note with the given amplitude (speed of decay).
void	controlChange (int number, StkFloat value, int string=-1)
	Perform the control change specified by number and value (0.0 - 128.0). More...
StkFloat	lastOut (void)
	Return the last computed output value.
StkFloat	tick (StkFloat input=0.0)
	Take an optional input sample and compute one output sample.
StkFrames &	tick (StkFrames &frames, unsigned int channel=0)
	Take a channel of the iFrames object as inputs to the class and write outputs to the oFrames object. More...
StkFrames &	tick (StkFrames &iFrames, StkFrames &oFrames, unsigned int iChannel=0, unsigned int oChannel=0)
	Take a channel of the iFrames object as inputs to the effect and write outputs to the oFrames object. More...
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 guitar model class.

This class implements a guitar model with an arbitrary number of strings (specified during instantiation). Each string is represented by an stk::Twang object. The model supports commuted synthesis, as discussed by Smith and Karjalainen. It also includes a basic body coupling model and supports feedback.

This class does not attempt voice management. Rather, most functions support a parameter to specify a particular string number and string (voice) management is assumed to occur externally. Note that this class does not inherit from stk::Instrmnt because of API inconsistencies.

This is a digital waveguide model, making its use possibly subject to patents held by Stanford University, Yamaha, and others.

Control Change Numbers:

• Bridge Coupling Gain = 2
• Pluck Position = 4
• Loop Gain = 11
• Coupling Filter Pole = 1
• Pick Filter Pole = 128

by Gary P. Scavone, 2012.

Member Function Documentation

setBodyFile()

void stk::Guitar::setBodyFile

(

std::string

bodyfile = ""

)

Set the string excitation, using either a soundfile or computed noise.

If no argument is provided, the std::string is empty, or an error occurs reading the file data, an enveloped noise signal will be generated for use as the pluck excitation.

setPluckPosition()

void stk::Guitar::setPluckPosition	(	StkFloat	position,
		int	string = -1
	)

Set the pluck position for one or all strings.

If the string argument is < 0, the pluck position is set for all strings.

setLoopGain()

void stk::Guitar::setLoopGain	(	StkFloat	gain,
		int	string = -1
	)

Set the loop gain for one or all strings.

If the string argument is < 0, the loop gain is set for all strings.

noteOn()

void stk::Guitar::noteOn	(	StkFloat	frequency,
		StkFloat	amplitude,
		unsigned int	string = 0
	)

Start a note with the given frequency and amplitude.

If the amplitude parameter is less than 0.2, the string will be undamped but it will not be "plucked."

controlChange()

void stk::Guitar::controlChange	(	int	number,
		StkFloat	value,
		int	string = -1
	)

Perform the control change specified by number and value (0.0 - 128.0).

If the string argument is < 0, then the control change is applied to all strings (if appropriate).

tick() [1/2]

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

inline

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

The iFrames object reference is returned. Each channel argument must be less than the number of channels in the corresponding StkFrames argument (the first channel 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 ( channel >= frames.channels() ) {
    oStream_ << "Guitar::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *samples = &frames[channel];
  unsigned int hop = frames.channels();
  for ( unsigned int i=0; i<frames.frames(); i++, samples += hop )
    *samples = tick( *samples );
 
  return frames;
}

tick() [2/2]

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

inline

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

The iFrames object reference is returned. Each channel argument must be less than the number of channels in the corresponding StkFrames argument (the first channel 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 ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
    oStream_ << "Guitar::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *iSamples = &iFrames[iChannel];
  StkFloat *oSamples = &oFrames[oChannel];
  unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
  for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop )
    *oSamples = tick( *iSamples );
 
  return iFrames;
}

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:

• Guitar.h