git.sesse.net Git - pitch/blob - glpitch.cpp

   1 #include <SDL.h>
   2 #include <GL/gl.h>
   3
   4 #include "config.h"
   5 #include "linux_audio.h"
   6 #include "notes.h"
   7 #include "pitchdetector.h"
   8
   9 #define MIN_X -40
  10 #define MAX_X 5
  11
  12 double find_linear_pos(double freq)
  13 {
  14         return 12.0 * log2(freq / BASE_PITCH) - 3.0;
  15 }
  16
  17 #if COMPRESS_PITCH_DISPLAY
  18 // bend the scale a bit to get more precision around the interesting points
  19 double magnifying_glass(double x)
  20 {
  21         double sigma = PITCH_COMPRESSION_SIGMA;
  22         double div = 1.0 / sqrt(2.0 * sigma * sigma);
  23         return
  24                 erf((x - find_linear_pos(notes[0].freq)) * div) +
  25                 erf((x - find_linear_pos(notes[1].freq)) * div) +
  26                 erf((x - find_linear_pos(notes[2].freq)) * div) +
  27                 erf((x - find_linear_pos(notes[3].freq)) * div) +
  28                 erf((x - find_linear_pos(notes[4].freq)) * div) +
  29                 erf((x - find_linear_pos(notes[5].freq)) * div);
  30 }
  31
  32 // like nonlinear_func, but f(MIN_X) = MIN_X and f(MAX_X) = MAX_X
  33 double normalized_magnifying_glass(double x)
  34 {
  35         double y = magnifying_glass(x);
  36         double min_y = magnifying_glass(MIN_X);
  37         double max_y = magnifying_glass(MAX_X);
  38         return (y - min_y) * (MAX_X - MIN_X) / (max_y - min_y) + MIN_X;
  39 }
  40 #endif /* COMPRESS_PITCH_DISPLAY */
  41
  42 double find_display_pos(double freq)
  43 {
  44         double linear_pos = find_linear_pos(freq);
  45 #if COMPRESS_PITCH_DISPLAY
  46         return normalized_magnifying_glass(linear_pos);
  47 #else
  48         return linear_pos;
  49 #endif
  50 }
  51
  52 int main(void)
  53 {
  54         PitchDetector pd(SAMPLE_RATE, FFT_LENGTH, PAD_FACTOR, OVERLAP);
  55         snd_pcm_t *pcm = get_dsp_handle(SAMPLE_RATE);
  56
  57         SDL_Init(SDL_INIT_VIDEO);
  58         SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
  59         SDL_SetVideoMode(1024, 200, 32, SDL_OPENGL);
  60
  61         glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
  62         glClear(GL_COLOR_BUFFER_BIT);
  63         glDisable(GL_DEPTH_TEST);
  64
  65         for ( ;; ) {
  66                 SDL_Event event;
  67                 while (SDL_PollEvent(&event)) {
  68                         switch (event.type) {
  69                         case SDL_KEYUP:
  70                                 if (event.key.keysym.sym == SDLK_ESCAPE) {
  71                                         exit(0);
  72                                 }
  73                                 break;
  74                         case SDL_QUIT:
  75                                 exit(0);
  76                         }
  77                 }
  78
  79                 short buf[FFT_LENGTH / PAD_FACTOR / OVERLAP];
  80                 read_chunk(pcm, buf, FFT_LENGTH / PAD_FACTOR / OVERLAP);
  81                 std::pair<double, double> peak = pd.detect_pitch(buf);
  82
  83                 glMatrixMode(GL_PROJECTION);
  84                 glLoadIdentity();
  85                 glOrtho(MIN_X, MAX_X, 1.0f, 0.0f, 0.0f, 1.0f);
  86
  87                 glMatrixMode(GL_MODELVIEW);
  88                 glLoadIdentity();
  89
  90                 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  91                 glEnable(GL_BLEND);
  92
  93                 glBegin(GL_QUADS);
  94                 glColor4f(0.0, 0.0f, 0.0f, 0.05f);
  95                 glVertex2f(MIN_X, 0.0f);
  96                 glVertex2f(MIN_X, 1.0f);
  97                 glVertex2f(MAX_X, 1.0f);
  98                 glVertex2f(MAX_X, 0.0f);
  99                 glEnd();
 100
 101                 if (peak.second - log10(FFT_LENGTH) >= 0.0) {
 102                         double peak_pos = find_display_pos(peak.first);
 103                         double strength = peak.second / 40.0f;
 104
 105                         glEnable(GL_POLYGON_SMOOTH);
 106                         glBlendFunc(GL_SRC_ALPHA, GL_ONE);
 107                         glEnable(GL_POLYGON_SMOOTH);
 108
 109                         glBegin(GL_QUADS);
 110                         glColor4f(0.0f, strength, 1.0 - strength, 0.2f);
 111                         glVertex2f(peak_pos - 0.1, 0.0f);
 112                         glVertex2f(peak_pos - 0.1, 1.0f);
 113                         glVertex2f(peak_pos + 0.1, 1.0f);
 114                         glVertex2f(peak_pos + 0.1, 0.0f);
 115                         glEnd();
 116
 117                         glDisable(GL_POLYGON_SMOOTH);
 118                 }
 119
 120                 glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
 121                 glBegin(GL_LINES);
 122
 123                 for (int i = 0; i < 6; ++i) {
 124                         double pos = find_display_pos(notes[i].freq);
 125                         glVertex2f(pos, 0.0f);
 126                         glVertex2f(pos, 1.0f);
 127                 }
 128                 glEnd();
 129
 130                 SDL_GL_SwapBuffers();
 131         }
 132 }