Port from OSS to ALSA, as OSS is pretty much dying these days.

[pitch] / glpitch.cpp

diff --git a/glpitch.cpp b/glpitch.cpp
index 90c47b8502715ec95bda0f2a7e73a97c819dc26d..a168d79c5c4d3083bd4bf7766d2c9e46f6455a8c 100644 (file)
--- a/glpitch.cpp
+++ b/glpitch.cpp
@@ -9,15 +9,50 @@
 #define MIN_X -40
 #define MAX_X 5
 
-double find_pos(double freq)
+double find_linear_pos(double freq)
 {
        return 12.0 * log2(freq / BASE_PITCH) - 3.0;
 }
 
+#if COMPRESS_PITCH_DISPLAY
+// bend the scale a bit to get more precision around the interesting points
+double magnifying_glass(double x)
+{
+       double sigma = PITCH_COMPRESSION_SIGMA;
+       double div = 1.0 / sqrt(2.0 * sigma * sigma);
+       return
+               erf((x - find_linear_pos(notes[0].freq)) * div) +
+               erf((x - find_linear_pos(notes[1].freq)) * div) +
+               erf((x - find_linear_pos(notes[2].freq)) * div) +
+               erf((x - find_linear_pos(notes[3].freq)) * div) +
+               erf((x - find_linear_pos(notes[4].freq)) * div) +
+               erf((x - find_linear_pos(notes[5].freq)) * div);
+}
+
+// like nonlinear_func, but f(MIN_X) = MIN_X and f(MAX_X) = MAX_X
+double normalized_magnifying_glass(double x)
+{
+       double y = magnifying_glass(x);
+       double min_y = magnifying_glass(MIN_X);
+       double max_y = magnifying_glass(MAX_X);
+       return (y - min_y) * (MAX_X - MIN_X) / (max_y - min_y) + MIN_X;
+}
+#endif /* COMPRESS_PITCH_DISPLAY */
+
+double find_display_pos(double freq)
+{
+       double linear_pos = find_linear_pos(freq);
+#if COMPRESS_PITCH_DISPLAY
+       return normalized_magnifying_glass(linear_pos);
+#else
+       return linear_pos;
+#endif
+}
+
 int main(void)
 {
        PitchDetector pd(SAMPLE_RATE, FFT_LENGTH, PAD_FACTOR, OVERLAP);
-       int fd = get_dsp_fd(SAMPLE_RATE, FFT_LENGTH, OVERLAP);
+       snd_pcm_t *pcm = get_dsp_handle(SAMPLE_RATE);
 
        SDL_Init(SDL_INIT_VIDEO);
        SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
@@ -25,10 +60,24 @@ int main(void)
 
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
+       glDisable(GL_DEPTH_TEST);
 
        for ( ;; ) {
+               SDL_Event event;
+               while (SDL_PollEvent(&event)) {
+                       switch (event.type) {
+                       case SDL_KEYUP:
+                               if (event.key.keysym.sym == SDLK_ESCAPE) {
+                                       exit(0);
+                               }
+                               break;
+                       case SDL_QUIT:
+                               exit(0);
+                       }
+               }
+
                short buf[FFT_LENGTH / PAD_FACTOR / OVERLAP];
-               read_chunk(fd, buf, FFT_LENGTH / PAD_FACTOR / OVERLAP);
+               read_chunk(pcm, buf, FFT_LENGTH / PAD_FACTOR / OVERLAP);
                std::pair<double, double> peak = pd.detect_pitch(buf);
 
                glMatrixMode(GL_PROJECTION);
@@ -49,23 +98,30 @@ int main(void)
                glVertex2f(MAX_X, 0.0f);
                glEnd();
 
-               glBlendFunc(GL_SRC_ALPHA, GL_ONE);
+               if (peak.second - log10(FFT_LENGTH) >= 0.0) {
+                       double peak_pos = find_display_pos(peak.first);
+                       double strength = peak.second / 40.0f;
 
-               double peak_pos = find_pos(peak.first);
+                       glEnable(GL_POLYGON_SMOOTH);
+                       glBlendFunc(GL_SRC_ALPHA, GL_ONE);
+                       glEnable(GL_POLYGON_SMOOTH);
 
-               glBegin(GL_QUADS);      
-               glColor4f(0.0, 1.0f, 0.0f, 0.2f);
-               glVertex2f(peak_pos - 0.1, 0.0f);
-               glVertex2f(peak_pos - 0.1, 1.0f);
-               glVertex2f(peak_pos + 0.1, 1.0f);
-               glVertex2f(peak_pos + 0.1, 0.0f);
-               glEnd();
+                       glBegin(GL_QUADS);      
+                       glColor4f(0.0f, strength, 1.0 - strength, 0.2f);
+                       glVertex2f(peak_pos - 0.1, 0.0f);
+                       glVertex2f(peak_pos - 0.1, 1.0f);
+                       glVertex2f(peak_pos + 0.1, 1.0f);
+                       glVertex2f(peak_pos + 0.1, 0.0f);
+                       glEnd();
+
+                       glDisable(GL_POLYGON_SMOOTH);
+               }
 
                glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
                glBegin(GL_LINES);
 
                for (int i = 0; i < 6; ++i) {
-                       double pos = find_pos(notes[i].freq);
+                       double pos = find_display_pos(notes[i].freq);
                        glVertex2f(pos, 0.0f);
                        glVertex2f(pos, 1.0f);
                }