vg_audio_synth_bird.h

   1 #pragma once
   2
   3 #ifndef BIRD_SAMPLE_RATE
   4  #define BIRD_SAMPLE_RATE 44100
   5 #endif
   6
   7 struct synth_bird_signature
   8 {
   9    float length, pause,  /* timings in seconds */
  10          x0,x1,x2,x3,    /* polynomial coefficients for the fundemental */
  11          v0,v1,v2,v3;    /* volume of each oscillator */
  12
  13    int   lfo_hz;         /* LFO frequency (30-60hz) */
  14    float fm;             /* LFO modulation depth (+/- hz) */
  15 };
  16
  17 struct synth_bird
  18 {
  19    struct{
  20       int osc_main[4],
  21           osc_lfo;
  22       float volume[4];
  23
  24       float fundamental;
  25       int x, length,       /* position/length of signature in samples */
  26           gate, adsr,      /* adsr ranges 0->44100 */
  27           frame;           /* current frame of the pattern */
  28
  29       int   lfo_hz;
  30       float fm_depth;
  31
  32       int adsr_rise,
  33           adsr_fall;
  34    }
  35    rt;
  36
  37    struct synth_bird_settings{
  38       int tones[4][2];        /* fraction of the fundemental tone
  39                                  for each oscillator */
  40       float adsr_rise,        /* rise/fall in seconds */
  41             adsr_fall;
  42
  43       enum bird_lfo_wave{
  44          k_bird_lfo_sine_approx,
  45          k_bird_lfo_bipolar_poly
  46       }
  47       type;
  48
  49       int pattern_length;
  50       struct synth_bird_signature pattern[];
  51    }
  52    settings;
  53 };
  54
  55 void synth_bird_reset( struct synth_bird *bird );
  56 u32 synth_bird_get_length_in_samples( struct synth_bird *bird );
  57 void synth_bird_generate_samples( struct synth_bird *bird,
  58                                   float *stereo_buffer, int samples );