Inheritance diagram for AudioSynthWavetable:

Public Member Functions
	AudioSynthWavetable (void)
	Class constructor.

void	setInstrument (const instrument_data &instrument)
	Set the instrument_data struct to be used as the playback instrument. More...

void	amplitude (float v)
	Changes the amplitude to 'v'. More...

void	stop (void)
	Stop playing waveform. More...

void	playFrequency (float freq, int amp=DEFAULT_AMPLITUDE)
	Play waveform at defined frequency, amplitude. More...

void	playNote (int note, int amp=DEFAULT_AMPLITUDE)
	Play sample at specified note, amplitude. More...

bool	isPlaying (void)

void	setFrequency (float freq)
	Set various integer offsets to values that will produce intended frequencies. More...

virtual void	update (void)
	Called by the AudioStream library to fill the audio output buffer. More...

envelopeStateEnum	getEnvState (void)

Static Public Member Functions
static float	midi_volume_transform (int midi_amp)
	Scale midi_amp to a value between 0.0 and 1.0 using a logarithmic tranformation. More...

static float	noteToFreq (int note)
	Convert a MIDI note value to its corresponding frequency. More...

static int	freqToNote (float freq)
	Convert a frequency to the corressponding MIDI note value. More...

Member Function Documentation

void AudioSynthWavetable::amplitude ( float v )

inline

Changes the amplitude to 'v'.

A value of 0 will set the synth output to minimum amplitude (i.e., no output). A value of 1 will set the output to the maximum amplitude. Amplitude is set linearly with intermediate values.

Parameters

v	a value between 0.0 and 1.0

static int AudioSynthWavetable::freqToNote ( float freq )

inlinestatic

Convert a frequency to the corressponding MIDI note value.

Parameters

freq	the frequency value as a float to convert

Returns: a MIDI note (between 0 - 127)

static float AudioSynthWavetable::midi_volume_transform ( int midi_amp )

inlinestatic

Scale midi_amp to a value between 0.0 and 1.0 using a logarithmic tranformation.

Parameters

midi_amp a value between 0 and 127

Returns: a value between 0.0 to 1.0

static float AudioSynthWavetable::noteToFreq ( int note )

inlinestatic

Convert a MIDI note value to its corresponding frequency.

Parameters

note	a value between 0 and 127

Returns: a frequency

void AudioSynthWavetable::playFrequency	(	float	freq,
		int	amp = `DEFAULT_AMPLITUDE`
	)

Play waveform at defined frequency, amplitude.

Parameters

freq	Frequency of note to playback, value between 1.0 and half of AUDIO_SAMPLE_RATE_EXACT
amp	Amplitude scaling of note, value between 0-127, with 127 being base volume

void AudioSynthWavetable::playNote	(	int	note,
		int	amp = `DEFAULT_AMPLITUDE`
	)

Play sample at specified note, amplitude.

Parameters

note	Midi note number to playback, value between 0-127
amp	Amplitude scaling of playback, value between 0-127, with 127 being base volume

void AudioSynthWavetable::setFrequency ( float freq )

Set various integer offsets to values that will produce intended frequencies.

the main integer offset, tone_incr, is used to step through the current sample's 16-bit PCM audio sample. Specifically, the tone_incr is the rate at which the interpolation code in update() steps through uint32_t space. The remaining offset variables represent a minimum and maximum offset allowed for tone_incr, which allows for low-frequency variation in playback frequency (aka vibrato). Further details on implementation in update() and in sample_data.h.

Parameters

freq	frequency of the generated output (between 0 and the board-specific sample rate)

void AudioSynthWavetable::setInstrument ( const instrument_data & instrument )

inline

Set the instrument_data struct to be used as the playback instrument.

A wavetable uses a set of samples to generate sound. This function is used to set the instrument samples.

Parameters

instrument a struct of type instrument_data, commonly prodced from a decoded SoundFont file using the SoundFont Decoder Script which accompanies this library.

void AudioSynthWavetable::stop ( void )

Stop playing waveform.

Waveform does not immediately stop, but fades out based on release time.

void AudioSynthWavetable::update ( void )

virtual

Called by the AudioStream library to fill the audio output buffer.

The major parts are the interpoalation stage, and the volume envelope stage. Further details on implementation included inline.

Public Member Functions

Static Public Member Functions

Member Function Documentation