channels/gentone.c

   1 /* Generate a header file for a particular
   2    single or double frequency */
   3
   4 #include <stdio.h>
   5 #include <math.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <stdlib.h>
   9 #define CLIP 32635
  10 #define BIAS 0x84
  11 static float loudness=16384.0;
  12
  13 static int calc_samples(int freq)
  14 {
  15         int x, samples;
  16         /* Calculate the number of samples at 8000hz sampling
  17            we need to have this wave form */
  18         samples = 8000;
  19         /* Take out common 2's up to six times */
  20         for (x=0;x<6;x++)
  21                 if (!(freq % 2)) {
  22                         freq /= 2;
  23                         samples /= 2;
  24                 }
  25         /* Take out common 5's (up to three times */
  26         for (x=0;x<3;x++)
  27                 if (!(freq % 5)) {
  28                         freq /= 5;
  29                         samples /=5;
  30                 }
  31         /* No more common factors. */
  32         return samples;
  33 }
  34
  35 int main(int argc, char *argv[])
  36 {
  37         FILE *f;
  38         int freq1, freq2;
  39         float wlen1, wlen2;
  40         float val;
  41         int x, samples1, samples2=0, samples=0;
  42         char fn[256];
  43         if (argc < 3) {
  44                 fprintf(stderr, "Usage: gensound <name> <freq1> [freq2]\n");
  45                 exit(1);
  46         }
  47         freq1 = atoi(argv[2]);
  48         if (argc > 3)
  49                 freq2 = atoi(argv[3]);
  50         else
  51                 freq2 = 0;
  52         wlen1 = 8000.0/(float)freq1;
  53         samples1 = calc_samples(freq1);
  54         printf("Wavelength 1 (in samples): %10.5f\n", wlen1);
  55         printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples1, samples1 / wlen1);
  56         if (freq2) {
  57                 wlen2 = 8000.0/(float)freq2;
  58                 samples2 = calc_samples(freq2);
  59                 printf("Wavelength 1 (in samples): %10.5f\n", wlen2);
  60                 printf("Minimum samples (1): %d (%f.3 wavelengths)\n", samples2, samples2 / wlen2);
  61         }
  62         samples = samples1;
  63         if (freq2) {
  64                 while(samples % samples2)
  65                         samples += samples1;
  66         }
  67         printf("Need %d samples\n", samples);
  68         snprintf(fn, sizeof(fn), "%s.h", argv[1]);
  69         if ((f = fopen(fn, "w"))) {
  70                 if (freq2)
  71                         fprintf(f, "/* %s: Generated from frequencies %d and %d \n"
  72                                    "   by gentone.  %d samples  */\n", fn, freq1, freq2, samples);
  73                 else
  74                         fprintf(f, "/* %s: Generated from frequency %d\n"
  75                                    "   by gentone.  %d samples  */\n", fn, freq1, samples);
  76                 fprintf(f, "static short %s[%d] = {\n\t", argv[1], samples);
  77                 for (x=0;x<samples;x++) {
  78                         val = loudness * sin((freq1 * 2.0 * M_PI * x)/8000.0);
  79                         if (freq2)
  80                                 val += loudness * sin((freq2 * 2.0 * M_PI * x)/8000.0);
  81                         fprintf(f, "%5d, ", (int)val);
  82                         if (!((x+1) % 8))
  83                                 fprintf(f, "\n\t");
  84                 }
  85                 if (x % 15)
  86                         fprintf(f, "\n");
  87                 fprintf(f, "};\n");
  88                 fclose(f);
  89                 printf("Wrote %s\n", fn);
  90         } else {
  91                 fprintf(stderr, "Unable to open %s for writing\n", fn);
  92                 return 1;
  93         }
  94         return 0;
  95 }