Add support for pedal

As scherzo listens to the pedal, it will analyze the chord harmony based on
notes that continue to sustain due to the pedal.

I'm not 100% comfortable with the empirically-derived value of 64 for
the sustain pedal. I'd feel a bit better if I had found a symbolic
constant for this in the ALSA header files. As things stand now, I'm
not sure if the sustain pedal on another keyboard will return the same
value.

diff --git a/scherzo.c b/scherzo.c
index 55a2cc98d40d00b7f80f40d572a07846a6351c76..676f5b459001412ad4ce7c4605dbc07e007cba8c 100644 (file)
--- a/scherzo.c
+++ b/scherzo.c
@@ -41,6 +41,14 @@ typedef struct challenge
     int mistaken;
 } challenge_t;
 
+typedef struct note_group
+{
+    void *ctx;
+    score_note_t **notes;
+    int size;
+    int num_notes;
+} note_group_t;
+
 typedef struct scherzo
 {
     void *ctx;
@@ -62,16 +70,24 @@ typedef struct scherzo
     mnemon_t mnemon;
     challenge_t challenge;
 
-    int num_notes_pressed;
-    score_note_t **notes_pressed;
+    note_group_t notes_pressed;
+    note_group_t notes_pedaled;
+
+    int pedal_pressed;
 } scherzo_t;
 
 /* Forward declarations. */
 static score_note_t *
-scherzo_add_note (scherzo_t *scherzo, score_pitch_t pitch, int octave);
+scherzo_press_note (scherzo_t *scherzo, score_pitch_t pitch, int octave);
 
 static void
-scherzo_remove_note (scherzo_t *scherzo, score_pitch_t pitch, int octave);
+scherzo_release_note (scherzo_t *scherzo, score_pitch_t pitch, int octave);
+
+static void
+scherzo_press_pedal (scherzo_t *scherzo);
+
+static void
+scherzo_release_pedal (scherzo_t *scherzo);
 
 static void
 _judge_note (scherzo_t *scherzo, score_note_t *note);
@@ -195,6 +211,9 @@ on_key_press_event (GtkWidget *widget,
     case GDK_KEY_8:
        scherzo->keyboard_octave = key->keyval - GDK_KEY_0;
        break;
+    case GDK_KEY_space:
+       scherzo_press_pedal (scherzo);
+       break;
     }
 
     if ((key->keyval >= GDK_KEY_A && key->keyval <= GDK_KEY_G) ||
@@ -202,7 +221,7 @@ on_key_press_event (GtkWidget *widget,
     {
        score_note_t *note;
 
-       note = scherzo_add_note (scherzo, pitch, octave);
+       note = scherzo_press_note (scherzo, pitch, octave);
        _judge_note (scherzo, note);
        gtk_widget_queue_draw (scherzo->window);
 
@@ -257,12 +276,15 @@ on_key_release_event (unused (GtkWidget *widget),
     case GDK_KEY_B:
        pitch = SCORE_PITCH_B;
        break;
+    case GDK_KEY_space:
+       scherzo_release_pedal (scherzo);
+       break;
     }
 
     if ((key->keyval >= GDK_KEY_A && key->keyval <= GDK_KEY_G) ||
        (key->keyval >= GDK_KEY_a && key->keyval <= GDK_KEY_g))
     {
-       scherzo_remove_note (scherzo, pitch, octave);
+       scherzo_release_note (scherzo, pitch, octave);
        _score_challenge (scherzo);
        gtk_widget_queue_draw (scherzo->window);
 
@@ -427,10 +449,18 @@ scherzo_analyze_chord (scherzo_t *scherzo)
 {
     void *local = talloc_new (NULL);
     analyzed_note_t *notes;
-    unsigned i, num_notes = scherzo->num_notes_pressed;
+    note_group_t *note_group;
+    unsigned i, num_notes;
     int bass_pitch;
     const char *chord_name = NULL;
 
+    if (scherzo->pedal_pressed)
+       note_group = &scherzo->notes_pedaled;
+    else
+       note_group = &scherzo->notes_pressed;
+
+    num_notes = note_group->num_notes;
+
     struct { int pitches[2]; const char *name; } intervals[] = {
        { {0, 1}, "Minor 2nd"},
        { {0, 2}, "Major 2nd"},
@@ -477,7 +507,7 @@ scherzo_analyze_chord (scherzo_t *scherzo)
        goto DONE;
 
     for (i = 0; i < num_notes; i++) {
-       score_note_t *note = scherzo->notes_pressed[i];
+       score_note_t *note = note_group->notes[i];
        notes[i].note = note;
        notes[i].midi_pitch = _score_pitch_and_octave_to_midi (note->pitch,
                                                               note->octave);
@@ -517,8 +547,51 @@ DONE:
     talloc_free (local);
 }
 
+static void
+note_group_init (void *ctx, note_group_t *group)
+{
+    group->ctx = ctx;
+    group->notes = NULL;
+    group->size = 0;
+    group->num_notes = 0;
+}
+
+static void
+note_group_add_note (note_group_t *group, score_note_t *note)
+{
+    group->num_notes++;
+
+    if (group->num_notes > group->size) {
+       group->size++;
+       group->notes = talloc_realloc (group->ctx, group->notes,
+                                      score_note_t*, group->size);
+
+       if (group->notes == NULL) {
+           fprintf (stderr, "Out of memory.\n");
+           exit (1);
+       }
+    }
+
+    group->notes[group->num_notes - 1] = note;
+}
+
+static void
+note_group_remove_note_at (note_group_t *group, int i)
+{
+    if (i >= group->num_notes) {
+       fprintf (stderr, "Internal error: No note to remove at index %d\n", i);
+       exit (1);
+    }
+
+    if (i < group->num_notes - 1) {
+       memmove (group->notes + i, group->notes + i + 1,
+                (group->num_notes - 1 - i) * sizeof (score_note_t*));
+    }
+    group->num_notes--;
+}
+
 static score_note_t *
-scherzo_add_note (scherzo_t *scherzo, score_pitch_t pitch, int octave)
+scherzo_press_note (scherzo_t *scherzo, score_pitch_t pitch, int octave)
 {
     score_staff_t *staff;
     score_note_t *note;
@@ -533,78 +606,109 @@ scherzo_add_note (scherzo_t *scherzo, score_pitch_t pitch, int octave)
     }
 
     /* Do nothing if this note is already pressed. */
-    for (i = 0; i < scherzo->num_notes_pressed; i++) {
-       if (scherzo->notes_pressed[i]->pitch == pitch &&
-           scherzo->notes_pressed[i]->octave == octave)
+    for (i = 0; i < scherzo->notes_pressed.num_notes; i++) {
+       if (scherzo->notes_pressed.notes[i]->pitch == pitch &&
+           scherzo->notes_pressed.notes[i]->octave == octave)
        {
-           return scherzo->notes_pressed[i];
+           return scherzo->notes_pressed.notes[i];
        }
     }
 
     note = score_add_note (staff, pitch, octave, SCORE_DURATION_WHOLE);
 
-    scherzo->num_notes_pressed++;
-    scherzo->notes_pressed = talloc_realloc (scherzo->ctx,
-                                            scherzo->notes_pressed,
-                                            score_note_t*,
-                                            scherzo->num_notes_pressed);
-    if (scherzo->notes_pressed == NULL) {
-       fprintf (stderr, "Out of memory.\n");
-       exit (1);
-    }
+    note_group_add_note (&scherzo->notes_pressed, note);
 
-    scherzo->notes_pressed[scherzo->num_notes_pressed - 1] = note;
+    if (scherzo->pedal_pressed)
+       note_group_add_note (&scherzo->notes_pedaled, note);
 
     scherzo_analyze_chord (scherzo);
 
     return note;
 }
 
-
 static void
-scherzo_remove_note (scherzo_t *scherzo, score_pitch_t pitch, int octave)
+scherzo_release_note (scherzo_t *scherzo, score_pitch_t pitch, int octave)
 {
     score_note_t *note;
     int i;
+    int found = 0;
 
-    for (i = 0; i < scherzo->num_notes_pressed; i++) {
-       note = scherzo->notes_pressed[i];
+    for (i = scherzo->notes_pressed.num_notes - 1; i >=0; i--) {
+       note = scherzo->notes_pressed.notes[i];
        if (note->pitch == pitch && note->octave == octave) {
-           score_remove_note (note);
-           if (i < scherzo->num_notes_pressed - 1) {
-               memmove (scherzo->notes_pressed + i,
-                        scherzo->notes_pressed + i + 1,
-                        (scherzo->num_notes_pressed - 1 - i) * sizeof (score_note_t*));
-           }
-           scherzo->num_notes_pressed--;
-           i--;
+           found = 1;
+           if (! scherzo->pedal_pressed)
+               score_remove_note (note);
+           note_group_remove_note_at (&scherzo->notes_pressed, i);
        }
     }
 
+    if (found == 0) {
+       fprintf (stderr, "Internal error: Failed to find note to release.\n");
+    }
+
     scherzo_analyze_chord (scherzo);
 }
 
 static score_note_t *
-scherzo_add_note_midi (scherzo_t *scherzo, unsigned char midi_note)
+scherzo_press_note_midi (scherzo_t *scherzo, unsigned char midi_note)
 {
     score_pitch_t pitch;
     int octave;
 
     _midi_to_score_pitch_and_octave (midi_note, &pitch, &octave);
 
-    return scherzo_add_note (scherzo, pitch, octave);
+    return scherzo_press_note (scherzo, pitch, octave);
 }
 
-
 static void
-scherzo_remove_note_midi (scherzo_t *scherzo, unsigned char midi_note)
+scherzo_release_note_midi (scherzo_t *scherzo, unsigned char midi_note)
 {
     score_pitch_t pitch;
     int octave;
  
     _midi_to_score_pitch_and_octave (midi_note, &pitch, &octave);
 
-    scherzo_remove_note (scherzo, pitch, octave);
+    scherzo_release_note (scherzo, pitch, octave);
+}
+
+static void
+scherzo_press_pedal (scherzo_t *scherzo)
+{
+    int i;
+
+    scherzo->pedal_pressed = 1;
+
+    /* Copy all pressed notes to pedaled notes */
+    for (i = 0; i < scherzo->notes_pressed.num_notes; i++)
+       note_group_add_note (&scherzo->notes_pedaled, scherzo->notes_pressed.notes[i]);
+}
+
+static void
+scherzo_release_pedal (scherzo_t *scherzo)
+{
+    score_note_t *note, *new_note;
+    int i;
+
+    /* Make new notes in score for all pressed notes. */
+    for (i = 0; i < scherzo->notes_pressed.num_notes; i++) {
+       note = scherzo->notes_pressed.notes[i];
+       new_note = score_add_note (note->staff, note->pitch, note->octave, note->duration);
+       scherzo->notes_pressed.notes[i] = new_note;
+    }
+
+    /* Then remove all previously pedaled notes from the score. */
+    for (i = scherzo->notes_pedaled.num_notes - 1; i >=0; i--) {
+       note = scherzo->notes_pedaled.notes[i];
+       score_remove_note (note);
+       note_group_remove_note_at (&scherzo->notes_pedaled, i);
+    }
+
+    scherzo->pedal_pressed = 0;
+
+    scherzo_analyze_chord (scherzo);
+
+    gtk_widget_queue_draw (scherzo->window);
 }
 
 void
@@ -758,12 +862,12 @@ on_midi_input (unused (GIOChannel *channel),
            /* Incomplete event. Nothing to do. */
            break;
        case SND_SEQ_EVENT_NOTEON:
-           note = scherzo_add_note_midi (scherzo, event.data.note.note);
+           note = scherzo_press_note_midi (scherzo, event.data.note.note);
            _judge_note (scherzo, note);
            need_redraw = TRUE;
            break;
        case SND_SEQ_EVENT_NOTEOFF:
-           scherzo_remove_note_midi (scherzo, event.data.note.note);
+           scherzo_release_note_midi (scherzo, event.data.note.note);
            _score_challenge (scherzo);
            need_redraw = TRUE;
            break;
@@ -773,6 +877,19 @@ on_midi_input (unused (GIOChannel *channel),
        case SND_SEQ_EVENT_SENSING:
            /* Ignore for now as my piano sends a constant stream of these. */
            break;
+       case SND_SEQ_EVENT_CONTROLLER:
+           /* XXX: My piano gives me 64 for the sustain pedal, is
+            * that universal? */
+           if (event.data.control.param == 64) {
+               if (event.data.control.value == 0)
+                   scherzo_release_pedal (scherzo);
+               else
+                   scherzo_press_pedal (scherzo);
+           } else {
+               fprintf (stderr, "Fixme: Unhandled MIDI Control event (param=%d, value=%d)\n",
+                        event.data.control.param, event.data.control.value);
+           }
+           break;
        default:
            fprintf (stderr, "Fixme: Do not yet know how to handle MIDI event %d\n",
                     event.type);
@@ -813,8 +930,10 @@ main (int argc, char *argv[])
     /* Default to octave 4 for computer keyboard keypresses. */
     scherzo.keyboard_octave = 4;
 
-    scherzo.num_notes_pressed = 0;
-    scherzo.notes_pressed = NULL;
+    note_group_init (scherzo.ctx, &scherzo.notes_pressed);
+    note_group_init (scherzo.ctx, &scherzo.notes_pedaled);
+
+    scherzo.pedal_pressed = 0;
 
     mnemon_init (&scherzo.mnemon);
     /* XXX: Should create a default file if one cannot be loaded. */