libfluidsynth  2.0.1
fluidsynth_arpeggio.c

Example of an arpeggio generated using the MIDI sequencer API

/* FluidSynth Arpeggio - Sequencer API example
*
* This code is in the public domain.
*
* To compile:
* gcc -o fluidsynth_arpeggio -lfluidsynth fluidsynth_arpeggio.c
*
* To run:
* fluidsynth_arpeggio soundfont [steps [duration]]
*
* [Pedro Lopez-Cabanillas <plcl@users.sf.net>]
*/
#include <stdlib.h>
#include <stdio.h>
#include <fluidsynth.h>
fluid_audio_driver_t *audiodriver;
fluid_sequencer_t *sequencer;
short synth_destination, client_destination;
unsigned int time_marker;
/* duration of the pattern in ticks. */
unsigned int duration = 1440;
/* notes of the arpeggio */
unsigned int notes[] = { 60, 64, 67, 72, 76, 79, 84, 79, 76, 72, 67, 64 };
/* number of notes in one pattern */
unsigned int pattern_size;
/* prototype */
void
sequencer_callback(unsigned int time, fluid_event_t *event,
fluid_sequencer_t *seq, void *data);
/* schedule a note on message */
void
schedule_noteon(int chan, short key, unsigned int ticks)
{
fluid_event_set_dest(ev, synth_destination);
fluid_event_noteon(ev, chan, key, 127);
fluid_sequencer_send_at(sequencer, ev, ticks, 1);
}
/* schedule a note off message */
void
schedule_noteoff(int chan, short key, unsigned int ticks)
{
fluid_event_set_dest(ev, synth_destination);
fluid_event_noteoff(ev, chan, key);
fluid_sequencer_send_at(sequencer, ev, ticks, 1);
}
/* schedule a timer event (shall trigger the callback) */
void
schedule_timer_event()
{
fluid_event_set_dest(ev, client_destination);
fluid_event_timer(ev, NULL);
fluid_sequencer_send_at(sequencer, ev, time_marker, 1);
}
/* schedule the arpeggio's notes */
void
schedule_pattern()
{
int i, note_time, note_duration;
note_time = time_marker;
note_duration = duration / pattern_size;
for(i = 0; i < pattern_size; ++i)
{
schedule_noteon(0, notes[i], note_time);
note_time += note_duration;
schedule_noteoff(0, notes[i], note_time);
}
time_marker += duration;
}
void
sequencer_callback(unsigned int time, fluid_event_t *event,
fluid_sequencer_t *seq, void *data)
{
schedule_timer_event();
schedule_pattern();
}
void
usage(char *prog_name)
{
printf("Usage: %s soundfont.sf2 [steps [duration]]\n", prog_name);
printf("\t(optional) steps: number of pattern notes, from 2 to %d\n",
pattern_size);
printf("\t(optional) duration: of the pattern in ticks, default %d\n",
duration);
}
int
main(int argc, char *argv[])
{
int n;
fluid_settings_t *settings;
settings = new_fluid_settings();
pattern_size = sizeof(notes) / sizeof(int);
if(argc < 2)
{
usage(argv[0]);
}
else
{
/* create the synth, driver and sequencer instances */
synth = new_fluid_synth(settings);
audiodriver = new_fluid_audio_driver(settings, synth);
sequencer = new_fluid_sequencer();
/* register the synth with the sequencer */
synth_destination = fluid_sequencer_register_fluidsynth(sequencer,
synth);
/* register the client name and callback */
client_destination = fluid_sequencer_register_client(sequencer,
"arpeggio", sequencer_callback, NULL);
/* load a SoundFont */
n = fluid_synth_sfload(synth, argv[1], 1);
if(n != -1)
{
if(argc > 2)
{
n = atoi(argv[2]);
if((n > 1) && (n <= pattern_size))
{
pattern_size = n;
}
}
if(argc > 3)
{
n = atoi(argv[3]);
if(n > 0)
{
duration = n;
}
}
/* get the current time in ticks */
time_marker = fluid_sequencer_get_tick(sequencer);
/* schedule patterns */
schedule_pattern();
schedule_timer_event();
schedule_pattern();
/* wait for user input */
printf("press <Enter> to stop\n");
n = getchar();
}
/* clean and exit */
}
return 0;
}