Mozzi  alpha 0.01.1t
sound synthesis library for Arduino
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Oscil< NUM_TABLE_CELLS, UPDATE_RATE > Class Template Reference

Oscil plays a wavetable, cycling through the table to generate an audio or control signal. More...

List of all members.

Public Member Functions

 Oscil (const char *TABLE_NAME)
 Constructor.
 Oscil ()
 Constructor.
char next ()
 Updates the phase according to the current frequency and returns the sample at the new phase position.
void setTable (const char *TABLE_NAME)
 Change the sound table which will be played by the Oscil.
void setPhase (unsigned int phase)
 Set the phase of the Oscil.
void setPhaseFractional (unsigned long phase)
 Set the phase of the Oscil.
unsigned long getPhaseFractional ()
 Get the phase of the Oscil in fractional format.
char phMod (Q15n16 phmod_proportion)
 Returns the next sample given a phase modulation value.
void setFreq (unsigned int frequency)
 Set the oscillator frequency with an unsigned int.
void setFreq (float frequency)
 Set the oscillator frequency with a float.
void setFreq_Q24n8 (Q24n8 frequency)
 Set the frequency using Q24n8 fixed-point number format.
void setFreq_Q16n16 (Q16n16 frequency)
 Set the frequency using Q16n16 fixed-point number format.
char atIndex (unsigned int index)
 Returns the sample at the given table index.
unsigned long phaseIncFromFreq (unsigned int frequency)
 phaseIncFromFreq() and setPhaseInc() are for saving processor time when sliding between frequencies.
void setPhaseInc (unsigned long phaseinc_fractional)
 Set a specific phase increment.

Detailed Description

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
class Oscil< NUM_TABLE_CELLS, UPDATE_RATE >

Oscil plays a wavetable, cycling through the table to generate an audio or control signal.

The frequency of the signal can be set or changed with setFreq(), and the output of an Oscil can be produced with next() for a simple cycling oscillator, or atIndex() for a particular sample in the table.

Template Parameters:
NUM_TABLE_CELLSThis is defined in the table ".h" file the Oscil will be using. It's important that it's a power of 2, and either a literal number (eg. "8192") or a defined macro, rather than a const or int, for the Oscil to run fast enough.
UPDATE_RATEThis will be AUDIO_RATE if the Oscil is updated in updateAudio(), or CONTROL_RATE if it's updated each time updateControl() is called. It could also be a fraction of CONTROL_RATE if you are doing some kind of cyclic updating in updateControl(), for example, to spread out the processor load.
Todo:
Use conditional compilation to optimise setFreq() variations for different table sizes.
Note:
If you #define OSCIL_DITHER_PHASE before you #include <Oscil.h>, the phase increments will be dithered, which reduces spurious frequency spurs in the audio output, at the cost of some extra processing and memory.

char2mozzi

Converting soundfiles for Mozzi There is a python script called char2mozzi.py in the Mozzi/python folder. The usage is: python char2mozzi.py infilename outfilename tablename samplerate

Definition at line 71 of file Oscil.h.


Constructor & Destructor Documentation

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::Oscil ( const char *  TABLE_NAME) [inline]

Constructor.

Parameters:
TABLE_NAMEthe name of the array the Oscil will be using. This can be found in the table ".h" file if you are using a table made for Mozzi by the char2mozzi.py python script in Mozzi's python folder.

Definition at line 81 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::Oscil ( ) [inline]

Constructor.

Declare an Oscil with template TABLE_NUM_CELLS and UPDATE_RATE parameters, without specifying a particular wave table for it to play. The table can be set or changed on the fly with setTable(). Any tables used by the Oscil must be the same size.

Definition at line 91 of file Oscil.h.


Member Function Documentation

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
char Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::atIndex ( unsigned int  index) [inline]

Returns the sample at the given table index.

Parameters:
atIndextable index between 0 and the table size.The index rolls back around to 0 if it's larger than the table size.
Returns:
the sample at the given table index.

Definition at line 253 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
unsigned long Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::getPhaseFractional ( ) [inline]

Get the phase of the Oscil in fractional format.

Parameters:
phasea position in the wavetable.

Definition at line 150 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
char Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::next ( ) [inline]

Updates the phase according to the current frequency and returns the sample at the new phase position.

Returns:
the next sample.

Definition at line 100 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
unsigned long Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::phaseIncFromFreq ( unsigned int  frequency) [inline]

phaseIncFromFreq() and setPhaseInc() are for saving processor time when sliding between frequencies.

Instead of recalculating the phase increment for each frequency in between, you can just calculate the phase increment for each end frequency with phaseIncFromFreq(), then use a Line to interpolate on the fly and use setPhaseInc() to set the phase increment at each step. (Note: I should really profile this with the oscilloscope to see if it's worth the extra confusion!)

Parameters:
frequencyfor which you want to calculate a phase increment value.
Returns:
the phase increment value which will produce a given frequency.

Definition at line 271 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
char Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::phMod ( Q15n16  phmod_proportion) [inline]

Returns the next sample given a phase modulation value.

Parameters:
aphase modulation value given as a proportion of the wave. The phmod_proportion parameter is a Q15n16 fixed-point number where the fractional n16 part represents -1 to 1, modulating the phase by one whole table length in each direction.
Returns:
a sample from the table.

Definition at line 171 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setFreq ( unsigned int  frequency) [inline]

Set the oscillator frequency with an unsigned int.

This is faster than using a float, so it's useful when processor time is tight, but it can be tricky with low and high frequencies, depending on the size of the wavetable being used. If you're not getting the results you expect, try explicitly using a float, or try setFreq_Q24n8() or or setFreq_Q16n16().

Parameters:
frequencyto play the wave table.

Definition at line 186 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setFreq ( float  frequency) [inline]

Set the oscillator frequency with a float.

Using a float is the most reliable way to set frequencies, -Might- be slower than using an int but you need either this, setFreq_Q24n8() or setFreq_Q16n16() for fractional frequencies.

Parameters:
frequencyto play the wave table.

Definition at line 200 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setFreq_Q16n16 ( Q16n16  frequency) [inline]

Set the frequency using Q16n16 fixed-point number format.

This is useful in combination with Q16n16_mtof(), a fast alternative to mtof(), using Q16n16 fixed-point format instead of floats. Note: this should work OK with tables 2048 cells or smaller and frequencies up to 4096 Hz. Can't be used with UPDATE_RATE less than 64 Hz.

Parameters:
frequencyin Q16n16 fixed-point number format.

Definition at line 235 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setFreq_Q24n8 ( Q24n8  frequency) [inline]

Set the frequency using Q24n8 fixed-point number format.

This might be faster than the float version for setting low frequencies such as 1.5 Hz, or other values which may not work well with your table size. A Q24n8 representation of 1.5 is 384 (ie. 1.5 * 256). Can't be used with UPDATE_RATE less than 64 Hz.

Parameters:
frequencyin Q24n8 fixed-point number format.

Definition at line 217 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setPhase ( unsigned int  phase) [inline]

Set the phase of the Oscil.

This does the same thing as Sample::start(offset). Just different ways of thinking about oscillators and samples.

Parameters:
phasea position in the wavetable.
Todo:
Test commenting out ATOMIC_BLOCK in setPhase(), setFreq(), etc.

Definition at line 123 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setPhaseFractional ( unsigned long  phase) [inline]

Set the phase of the Oscil.

Might be useful with getPhaseFractional().

Parameters:
phasea position in the wavetable.
Todo:
Test commenting out ATOMIC_BLOCK in setPhase(), setFreq(), etc.

Definition at line 138 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setPhaseInc ( unsigned long  phaseinc_fractional) [inline]

Set a specific phase increment.

See phaseIncFromFreq().

Parameters:
phaseinc_fractionala phase increment value as calculated by phaseIncFromFreq().

Definition at line 281 of file Oscil.h.

template<unsigned int NUM_TABLE_CELLS, unsigned int UPDATE_RATE>
void Oscil< NUM_TABLE_CELLS, UPDATE_RATE >::setTable ( const char *  TABLE_NAME) [inline]

Change the sound table which will be played by the Oscil.

Parameters:
TABLE_NAMEis the name of the array in the table ".h" file you're using.

Definition at line 110 of file Oscil.h.


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