ptttl_sample_generator.h File Reference

Converts the output of ptttl_parse_next() into a stream of signed 16-bit audio samples suitable for a WAV file. Samples can be obtained one at a time, at your leisure. More...

#include <stdint.h>
#include "ptttl_parser.h"

Go to the source code of this file.

Classes
struct	ptttl_note_stream_t
struct	ptttl_sample_generator_config_t
struct	ptttl_sample_generator_t

Macros
#define	PTTTL_SAMPLE_GENERATOR_CONFIG_DEFAULT

Typedefs
typedef float(*	ptttl_waveform_generator_t) (float x, float p, unsigned int s)

Enumerations
enum	ptttl_waveform_type_e {   WAVEFORM_TYPE_SINE = 0 , WAVEFORM_TYPE_TRIANGLE , WAVEFORM_TYPE_SAWTOOTH , WAVEFORM_TYPE_SQUARE ,   WAVEFORM_TYPE_COUNT }

Functions
int	ptttl_sample_generator_create (ptttl_parser_t *parser, ptttl_sample_generator_t *generator, ptttl_sample_generator_config_t *config)
int	ptttl_sample_generator_set_waveform (ptttl_sample_generator_t *generator, uint32_t channel, ptttl_waveform_type_e type)
int	ptttl_sample_generator_set_custom_waveform (ptttl_sample_generator_t *generator, uint32_t channel, ptttl_waveform_generator_t wgen)
int	ptttl_sample_generator_generate (ptttl_sample_generator_t *generator, uint32_t *num_samples, int16_t *samples)

Detailed Description

Converts the output of ptttl_parse_next() into a stream of signed 16-bit audio samples suitable for a WAV file. Samples can be obtained one at a time, at your leisure.

Requires ptttl_parser.c

Requires stdint.h and memset() from string.h

See https://github.com/eriknyquist/ptttl for more details about PTTTL.

Author

Erik Nyquist

Macro Definition Documentation

PTTTL_SAMPLE_GENERATOR_CONFIG_DEFAULT

#define PTTTL_SAMPLE_GENERATOR_CONFIG_DEFAULT

Value:

                                               {.sample_rate=44100u, .attack_samples=100u, \
                                               .decay_samples=500u, .amplitude=0.8f}

ptttl_sample_generator_config_t object initialization with sane defaults

Typedef Documentation

ptttl_waveform_generator_t

typedef float(* ptttl_waveform_generator_t) (float x, float p, unsigned int s)

Callback function for a waveform generator

Parameters

x	Phase; current position on the waveform, in turns (0.0 through 1.0)
p	Wave frequency in Hz
s	Sampling rate in Hz

Returns

Value for the given position, in the range -1.0 through 1.0

Enumeration Type Documentation

ptttl_waveform_type_e

enum ptttl_waveform_type_e

Enumerates all available built-in waveform types

Enumerator
WAVEFORM_TYPE_SINE	Generates a sine wave.
WAVEFORM_TYPE_TRIANGLE	Generates a triangle wave.
WAVEFORM_TYPE_SAWTOOTH	Generates a sawtooth wave.
WAVEFORM_TYPE_SQUARE	Generates a square wave.

Function Documentation

ptttl_sample_generator_create()

int ptttl_sample_generator_create	(	ptttl_parser_t *	parser,
		ptttl_sample_generator_t *	generator,
		ptttl_sample_generator_config_t *	config
	)

Initialize a sample generator instance for a specific PTTTL/RTTTL source text

Parameters

parser	Pointer to initialized PTTTL parser object
generator	Pointer to generator instance to initialize
config	Pointer to sample generator configuration data

Returns

0 if successful, -1 if an error occurred. Call ptttl_parser_error for an error description if -1 is returned.

ptttl_sample_generator_generate()

int ptttl_sample_generator_generate	(	ptttl_sample_generator_t *	generator,
		uint32_t *	num_samples,
		int16_t *	samples
	)

Generate the next audio sample(s) for an initialized generator object

Parameters

generator	Pointer to initialized generator object
num_samples	Pointer to number of samples to generate. If successful, then this pointer is re-used to write out the actual number of samples generated.
samples	Pointer to location to store sample values. The caller is expected to provide at least (sizeof(int16_t) * num_samples) bytes of storage for the generated samples.

Returns

0 if successful, 1 if all samples have been generated, and -1 if an error occurred. Call ptttl_parser_error for an error description if -1 is returned.

ptttl_sample_generator_set_custom_waveform()

int ptttl_sample_generator_set_custom_waveform	(	ptttl_sample_generator_t *	generator,
		uint32_t	channel,
		ptttl_waveform_generator_t	wgen
	)

Set a custom waveform generator function for a specific channel of the sample generator

Parameters

generator	Pointer to initialized generator object
channel	Channel index to set the waveform type for. Channel index is 0-based, and channels are indexed in the order in which they appear in the PTTTL source text. For example, channel 0 is the first channel that appears in the source text, channel 1 is the second channel, and so on.
wgen	Waveform generator function to use for the specified channel.

Returns

0 if successful, -1 if an error occurred. Call ptttl_parser_error for an error description if -1 is returned.

ptttl_sample_generator_set_waveform()

int ptttl_sample_generator_set_waveform	(	ptttl_sample_generator_t *	generator,
		uint32_t	channel,
		ptttl_waveform_type_e	type
	)

Set the built-in waveform type for a specific channel of the sample generator

Parameters

generator	Pointer to initialized generator object
channel	Channel index to set the waveform type for. Channel index is 0-based, and channels are indexed in the order in which they appear in the PTTTL source text. For example, channel 0 is the first channel that appears in the source text, channel 1 is the second channel, and so on.
type	Built-in waveform type to generate for the specified channel.

Returns

0 if successful, -1 if an error occurred. Call ptttl_parser_error for an error description if -1 is returned.