example-clients/internal_metro.cpp

   1 /*
   2  Copyright (C) 2002 Anthony Van Groningen
   3  Copyright (C) 2005 Grame
   4
   5  This program is free software; you can redistribute it and/or modify
   6  it under the terms of the GNU General Public License as published by
   7  the Free Software Foundation; either version 2 of the License, or
   8  (at your option) any later version.
   9
  10  This program is distributed in the hope that it will be useful,
  11  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  GNU General Public License for more details.
  14
  15  You should have received a copy of the GNU General Public License
  16  along with this program; if not, write to the Free Software
  17  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #include "internal_metro.h"
  21
  22 typedef jack_default_audio_sample_t sample_t;
  23
  24 const double PI = 3.14;
  25
  26 static int process_audio (jack_nframes_t nframes, void* arg)
  27 {
  28     InternalMetro* metro = (InternalMetro*)arg;
  29     sample_t *buffer = (sample_t *) jack_port_get_buffer (metro->output_port, nframes);
  30     jack_nframes_t frames_left = nframes;
  31
  32     while (metro->wave_length - metro->offset < frames_left) {
  33         memcpy (buffer + (nframes - frames_left), metro->wave + metro->offset, sizeof (sample_t) * (metro->wave_length - metro->offset));
  34         frames_left -= metro->wave_length - metro->offset;
  35         metro->offset = 0;
  36     }
  37     if (frames_left > 0) {
  38         memcpy (buffer + (nframes - frames_left), metro->wave + metro->offset, sizeof (sample_t) * frames_left);
  39         metro->offset += frames_left;
  40     }
  41
  42     return 0;
  43 }
  44
  45 InternalMetro::InternalMetro(int freq, double max_amp, int dur_arg, int bpm, char* client_name)
  46 {
  47     sample_t scale;
  48     int i, attack_length, decay_length;
  49     double *amp;
  50     int attack_percent = 1, decay_percent = 10;
  51     const char *bpm_string = "bpm";
  52
  53     offset = 0;
  54
  55     /* Initial Jack setup, get sample rate */
  56     if (!client_name) {
  57         client_name = (char *) malloc (9 * sizeof (char));
  58         strcpy (client_name, "metro");
  59     }
  60     if ((client = jack_client_open (client_name, JackNullOption, NULL)) == 0) {
  61         fprintf (stderr, "jack server not running?\n");
  62         return ;
  63     }
  64
  65     jack_set_process_callback (client, process_audio, this);
  66     output_port = jack_port_register (client, bpm_string, JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
  67     input_port = jack_port_register (client, "metro_in", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
  68
  69     sr = jack_get_sample_rate (client);
  70
  71     /* setup wave table parameters */
  72     wave_length = 60 * sr / bpm;
  73     tone_length = sr * dur_arg / 1000;
  74     attack_length = tone_length * attack_percent / 100;
  75     decay_length = tone_length * decay_percent / 100;
  76     scale = 2 * PI * freq / sr;
  77
  78     if (tone_length >= wave_length) {
  79         /*
  80         fprintf (stderr, "invalid duration (tone length = %" PRIu32
  81                  ", wave length = %" PRIu32 "\n", tone_length,
  82                  wave_length);
  83         */
  84         return ;
  85     }
  86     if (attack_length + decay_length > (int)tone_length) {
  87         fprintf (stderr, "invalid attack/decay\n");
  88         return ;
  89     }
  90
  91     /* Build the wave table */
  92     wave = (sample_t *) malloc (wave_length * sizeof(sample_t));
  93     amp = (double *) malloc (tone_length * sizeof(double));
  94
  95     for (i = 0; i < attack_length; i++) {
  96         amp[i] = max_amp * i / ((double) attack_length);
  97     }
  98     for (i = attack_length; i < (int) tone_length - decay_length; i++) {
  99         amp[i] = max_amp;
 100     }
 101     for (i = (int)tone_length - decay_length; i < (int)tone_length; i++) {
 102         amp[i] = - max_amp * (i - (double) tone_length) / ((double) decay_length);
 103     }
 104     for (i = 0; i < (int) tone_length; i++) {
 105         wave[i] = amp[i] * sin (scale * i);
 106     }
 107     for (i = tone_length; i < (int) wave_length; i++) {
 108         wave[i] = 0;
 109     }
 110
 111     if (jack_activate (client)) {
 112         fprintf(stderr, "cannot activate client");
 113         return;
 114     }
 115 }
 116
 117 InternalMetro::~InternalMetro()
 118 {
 119     jack_deactivate(client);
 120     jack_port_unregister(client, input_port);
 121     jack_port_unregister(client, output_port);
 122     jack_client_close(client);
 123 }