]> git.cworth.org Git - scherzo/blobdiff - scherzo.c
Add support for recognizing inverted chords.
[scherzo] / scherzo.c
index 491489839c8cba69345f41d19a0f1879bbf1f97a..d6b3af55f8d56cf6dee4cc2fde49ae1c65fc4d59 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;
@@ -51,22 +59,37 @@ typedef struct scherzo
     score_staff_t *treble;
     score_staff_t *bass;
     score_chord_t *chord;
+
+    /* The word "keyboard" here is referring to a "computer
+     * keyboard". Any "piano keyboard" key knows its own octave and
+     * accidental already. */
+    int keyboard_octave;
+    score_pitch_accidental_t keyboard_accidental;
+
     int midi_fd;
     snd_midi_event_t *snd_midi_event;
 
     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);
@@ -124,12 +147,13 @@ on_key_press_event (GtkWidget *widget,
 {
     scherzo_t *scherzo = user_data;
     int octave;
+    score_pitch_name_t pitch_name;
     score_pitch_t pitch;
 
     if (scherzo->challenge.note)
        octave = scherzo->challenge.note->octave;
     else
-       octave = 4;
+       octave = scherzo->keyboard_octave;
 
     switch (key->keyval) {
     case GDK_KEY_plus:
@@ -153,40 +177,64 @@ on_key_press_event (GtkWidget *widget,
        return FALSE;
     case GDK_KEY_c:
     case GDK_KEY_C:
-       pitch = SCORE_PITCH_C;
+       pitch_name = SCORE_PITCH_NAME_C;
        break;
     case GDK_KEY_d:
     case GDK_KEY_D:
-       pitch = SCORE_PITCH_D;
+       pitch_name = SCORE_PITCH_NAME_D;
        break;
     case GDK_KEY_e:
     case GDK_KEY_E:
-       pitch = SCORE_PITCH_E;
+       pitch_name = SCORE_PITCH_NAME_E;
        break;
     case GDK_KEY_f:
     case GDK_KEY_F:
-       pitch = SCORE_PITCH_F;
+       pitch_name = SCORE_PITCH_NAME_F;
        break;
     case GDK_KEY_g:
     case GDK_KEY_G:
-       pitch = SCORE_PITCH_G;
+       pitch_name = SCORE_PITCH_NAME_G;
        break;
     case GDK_KEY_a:
     case GDK_KEY_A:
-       pitch = SCORE_PITCH_A;
+       pitch_name = SCORE_PITCH_NAME_A;
        break;
     case GDK_KEY_b:
     case GDK_KEY_B:
-       pitch = SCORE_PITCH_B;
+       pitch_name = SCORE_PITCH_NAME_B;
+       break;
+    case GDK_KEY_0:
+    case GDK_KEY_1:
+    case GDK_KEY_2:
+    case GDK_KEY_3:
+    case GDK_KEY_4:
+    case GDK_KEY_5:
+    case GDK_KEY_6:
+    case GDK_KEY_7:
+    case GDK_KEY_8:
+       scherzo->keyboard_octave = key->keyval - GDK_KEY_0;
+       break;
+    case GDK_KEY_space:
+       scherzo_press_pedal (scherzo);
+       break;
+    case GDK_KEY_Up:
+       if (scherzo->keyboard_accidental < SCORE_PITCH_ACCIDENTAL_DOUBLE_SHARP)
+           scherzo->keyboard_accidental++;
+       break;
+    case GDK_KEY_Down:
+       if (scherzo->keyboard_accidental > SCORE_PITCH_ACCIDENTAL_DOUBLE_FLAT)
+           scherzo->keyboard_accidental--;
        break;
     }
 
+    pitch = SCORE_PITCH (pitch_name, scherzo->keyboard_accidental);
+
     if ((key->keyval >= GDK_KEY_A && key->keyval <= GDK_KEY_G) ||
        (key->keyval >= GDK_KEY_a && key->keyval <= GDK_KEY_g))
     {
        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);
 
@@ -205,48 +253,54 @@ on_key_release_event (unused (GtkWidget *widget),
 {
     scherzo_t *scherzo = user_data;
     int octave;
+    score_pitch_name_t pitch_name;
     score_pitch_t pitch;
 
     if (scherzo->challenge.note)
        octave = scherzo->challenge.note->octave;
     else
-       octave = 4;
+       octave = scherzo->keyboard_octave;
 
     switch (key->keyval) {
     case GDK_KEY_c:
     case GDK_KEY_C:
-       pitch = SCORE_PITCH_C;
+       pitch_name = SCORE_PITCH_NAME_C;
        break;
     case GDK_KEY_d:
     case GDK_KEY_D:
-       pitch = SCORE_PITCH_D;
+       pitch_name = SCORE_PITCH_NAME_D;
        break;
     case GDK_KEY_e:
     case GDK_KEY_E:
-       pitch = SCORE_PITCH_E;
+       pitch_name = SCORE_PITCH_NAME_E;
        break;
     case GDK_KEY_f:
     case GDK_KEY_F:
-       pitch = SCORE_PITCH_F;
+       pitch_name = SCORE_PITCH_NAME_F;
        break;
     case GDK_KEY_g:
     case GDK_KEY_G:
-       pitch = SCORE_PITCH_G;
+       pitch_name = SCORE_PITCH_NAME_G;
        break;
     case GDK_KEY_a:
     case GDK_KEY_A:
-       pitch = SCORE_PITCH_A;
+       pitch_name = SCORE_PITCH_NAME_A;
        break;
     case GDK_KEY_b:
     case GDK_KEY_B:
-       pitch = SCORE_PITCH_B;
+       pitch_name = SCORE_PITCH_NAME_B;
+       break;
+    case GDK_KEY_space:
+       scherzo_release_pedal (scherzo);
        break;
     }
 
+    pitch = SCORE_PITCH (pitch_name, scherzo->keyboard_accidental);
+
     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);
 
@@ -369,41 +423,115 @@ typedef struct analyzed_note {
 } analyzed_note_t;
 
 static int
-_compare_analyzed_note (const void *va, const void *vb)
+_compare_analyzed_note_by_midi_pitch (const void *va, const void *vb)
 {
     const analyzed_note_t *a = va, *b = vb;
 
     return a->midi_pitch - b->midi_pitch;
 }
 
+static int
+_compare_analyzed_note_by_relative_pitch (const void *va, const void *vb)
+{
+    const analyzed_note_t *a = va, *b = vb;
+
+    return a->relative_pitch - b->relative_pitch;
+}
+
+typedef struct modified_degree
+{
+    int degree;
+    int modification;
+} modified_degree_t;
+
+static int
+_modified_degree_to_half_steps (const modified_degree_t *degree)
+{
+    int half_steps;
+
+    /* Number of half steps from root to specified degree within a
+     * diatonic scaled. */
+    switch (degree->degree) {
+    case 1:
+       half_steps = 0;
+       break;
+    case 2:
+       half_steps = 2;
+       break;
+    case 3:
+       half_steps = 4;
+       break;
+    case 4:
+       half_steps = 5;
+       break;
+    case 5:
+       half_steps = 7;
+       break;
+    case 6:
+       half_steps = 9;
+       break;
+    case 7:
+       half_steps = 11;
+       break;
+    default:
+       fprintf (stderr, "Internal: Invalid degree %d\n", degree->degree);
+       exit (1);
+       break;
+    }
+
+    return half_steps + degree->modification;
+}
+
 static int
 _chord_signature_matches (analyzed_note_t *notes,
                          int num_notes,
-                         int *signature_pitches,
-                         int num_signature_pitches)
+                         modified_degree_t *degrees,
+                         int num_degrees,
+                         int *inversion_ret)
 {
-    int n, s;
+#define MAX_DEGREES 4
+    int relative_pitches[MAX_DEGREES];
+    int inversion, max_inversions;
+    int i;
 
-    for (n = 0, s = 0; s < num_signature_pitches; s++) {
-       if (n >= num_notes)
-           return 0;
-       if (notes[n].relative_pitch != signature_pitches[s])
+    assert (num_degrees <= MAX_DEGREES);
+
+    if (num_notes != num_degrees)
            return 0;
-       n++;
-       /* Skip repeated notes in chord being tested. */
-       while (n < num_notes &&
-              notes[n].relative_pitch == signature_pitches[s])
-       {
-           n++;
+
+    max_inversions = num_degrees;
+
+    /* We never spell simple intervals as inversions. */
+    if (num_degrees == 2)
+       max_inversions = 1;
+
+    for (inversion = 0; inversion < max_inversions; inversion++) {
+       for (i = 0; i < num_degrees; i++) {
+           /* The num_degrees is in the addition just to ensure all
+            * inputs to the modulus operator remain positive. */
+           int index = (i + num_degrees - inversion) % num_degrees;
+
+           /* Again, adding a 12 to keep things positive. */
+           relative_pitches[index] =
+               (12 +
+                _modified_degree_to_half_steps (&degrees[i]) -
+                _modified_degree_to_half_steps (&degrees[inversion])) % 12;
+               
        }
-    }
 
-    /* If there are fewer notes in the signature than in the chord,
-     * then there is no match. */
-    if (n < num_notes)
-           return 0;
+       for (i = 0; i < num_notes; i++)
+           if (notes[i].relative_pitch != relative_pitches[i])
+               goto NEXT_INVERSION;
+
+       *inversion_ret = inversion;
+
+       return 1;
+
+    NEXT_INVERSION:
+       ;
+    }
 
-    return 1;
+    return 0;
 }
 
 static void
@@ -411,41 +539,53 @@ scherzo_analyze_chord (scherzo_t *scherzo)
 {
     void *local = talloc_new (NULL);
     analyzed_note_t *notes;
-    unsigned i, num_notes = scherzo->num_notes_pressed;
-    int bass_pitch;
+    note_group_t *note_group;
+    unsigned i, j, num_notes;
+    int bass_pitch, inversion;
     const char *chord_name = NULL;
 
-    struct { int pitches[2]; const char *name; } intervals[] = {
-       { {0, 1}, "Minor 2nd"},
-       { {0, 2}, "Major 2nd"},
-       { {0, 3}, "Minor 3rd"},
-       { {0, 4}, "Major 3rd"},
-       { {0, 5}, "Perfect 4th"},
-       { {0, 6}, "Diminished 5th/Augmented 4th"},
-       { {0, 7}, "Perfect 5th"},
-       { {0, 8}, "Minor 6th"},
-       { {0, 9}, "Major 6th"},
-       { {0, 10}, "Minor 7th"},
-       { {0, 11}, "Major 7th"}
+    if (scherzo->pedal_pressed)
+       note_group = &scherzo->notes_pedaled;
+    else
+       note_group = &scherzo->notes_pressed;
+
+    num_notes = note_group->num_notes;
+
+    struct { modified_degree_t degrees[1]; const char *name; } octaves[] = {
+       { {{1, 0}}, "Octave"}
     };
 
-    struct { int pitches[3]; const char *name; } triads[] = {
-       { {0, 4, 8}, "Augmented triad" },
-       { {0, 4, 7}, "Major triad" },
-       { {0, 3, 7}, "Minor triad" },
-       { {0, 3, 6}, "Diminished triad" }
+    struct { modified_degree_t degrees[2]; const char *name; } intervals[] = {
+       { {{1, 0}, {2, -1}}, "Minor 2nd"},
+       { {{1, 0}, {2,  0}}, "Major 2nd"},
+       { {{1, 0}, {3, -1}}, "Minor 3rd"},
+       { {{1, 0}, {3,  0}}, "Major 3rd"},
+       { {{1, 0}, {4,  0}}, "Perfect 4th"},
+       { {{1, 0}, {5, -1}}, "Diminished 5th"},
+       { {{1, 0}, {5,  0}}, "Perfect 5th"},
+       { {{1, 0}, {6, -1}}, "Minor 6th"},
+       { {{1, 0}, {6,  0}}, "Major 6th"},
+       { {{1, 0}, {7, -1}}, "Minor 7th"},
+       { {{1, 0}, {7,  0}}, "Major 7th"}
     };
 
-    struct { int pitches[4]; const char *name; } sevenths[] = {
-       { {0, 4, 8, 11}, "Augmented/major 7" },
-       { {0, 4, 7, 11}, "Major 7" },
-       { {0, 4, 7, 10}, "Dominant 7" },
-       { {0, 3, 7, 11}, "Minor/major 7" },
-       { {0, 3, 7, 10}, "Minor 7" },
-       { {0, 3, 6, 10}, "Half-diminished 7" },
-       { {0, 3, 6, 9},  "Diminished 7" },
-       { {0, 4, 8, 10}, "Augmented 7" },
-       { {0, 3, 6, 11}, "Diminished/major 7" },
+    struct { modified_degree_t degrees[3]; const char *name; } triads[] = {
+       { {{1, 0}, {3,  0}, {5, +1}}, "Augmented triad" },
+       { {{1, 0}, {3,  0}, {5,  0}}, "Major triad" },
+       { {{1, 0}, {3, -1}, {5,  0}}, "Minor triad" },
+       { {{1, 0}, {3, -1}, {5, -1}}, "Diminished triad" }
+    };
+
+    struct { modified_degree_t degrees[4]; const char *name; } sevenths[] = {
+       { {{1, 0}, {3,  0}, {5, +1}, {7,  0}}, "Augmented/major 7" },
+       { {{1, 0}, {3,  0}, {5, +1}, {7, -1}}, "Augmented 7" },
+       { {{1, 0}, {3,  0}, {5,  0}, {7,  0}}, "Major 7" },
+       { {{1, 0}, {3,  0}, {5,  0}, {7, -1}}, "Dominant 7" },
+       { {{1, 0}, {3, -1}, {5,  0}, {7,  0}}, "Minor/major 7" },
+       { {{1, 0}, {3, -1}, {5,  0}, {7, -1}}, "Minor 7" },
+       { {{1, 0}, {3, -1}, {5, -1}, {7,  0}}, "Diminished/major 7" },
+       { {{1, 0}, {3, -1}, {5, -1}, {7, -1}}, "Half-diminished 7" },
+       { {{1, 0}, {3, -1}, {5, -1}, {7, -2}}, "Diminished 7" }
     };
 
     if (scherzo->chord) {
@@ -453,7 +593,7 @@ scherzo_analyze_chord (scherzo_t *scherzo)
        scherzo->chord = NULL;
     }
 
-    if (num_notes == 0)
+    if (num_notes <= 1)
        goto DONE;
 
     notes = talloc_array (local, analyzed_note_t, num_notes);
@@ -461,7 +601,7 @@ 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);
@@ -469,123 +609,296 @@ scherzo_analyze_chord (scherzo_t *scherzo)
        notes[i].relative_pitch = 0;
     }
 
-    qsort (notes, num_notes, sizeof (analyzed_note_t), _compare_analyzed_note);
+    /* First, sort by midi pitch to find the bass note. */
+    qsort (notes, num_notes, sizeof (analyzed_note_t),
+          _compare_analyzed_note_by_midi_pitch);
     
     bass_pitch = notes[0].midi_pitch;
 
+    /* With the bass note identified, we can find all relative pitches. */
     for (i = 0; i < num_notes; i++) {
        notes[i].relative_pitch = notes[i].midi_pitch - bass_pitch;
+       while (notes[i].relative_pitch >= 12)
+           notes[i].relative_pitch -= 12;
     }
 
-    for (i = 0; i < ARRAY_SIZE (intervals); i++) {
-       if (_chord_signature_matches (notes, num_notes, intervals[i].pitches, 2))
-           chord_name = intervals[i].name;
+    /* Now, sort again by relative pitch. */
+    qsort (notes, num_notes, sizeof (analyzed_note_t),
+          _compare_analyzed_note_by_relative_pitch);
+
+    /* Finally, eliminate all duplicate notes. */
+    for (i = 0; i < num_notes - 1; i++) {
+           if (notes[i+1].relative_pitch == notes[i].relative_pitch) {
+                   j = i+1;
+                   while (j < num_notes &&
+                          notes[j].relative_pitch == notes[i].relative_pitch)
+                   {
+                           j++;
+                   }
+                   /* The loop incremented j one past the last
+                    * duplicate. Decrement so that it points to the
+                    * last duplicate (and is guaranteed to not exceed
+                    * the array bounds).*/
+                   j--;
+
+                   if (j < num_notes - 1) {
+                           memmove (&notes[i+1], &notes[j+1],
+                                    (num_notes - j) * sizeof (analyzed_note_t));
+                   }
+
+                   num_notes -= (j - i);
+           }
     }
 
-    for (i = 0; i < ARRAY_SIZE (triads); i++) {
-       if (_chord_signature_matches (notes, num_notes, triads[i].pitches, 3))
-           chord_name = triads[i].name;
+    switch (num_notes) {
+    case 1:
+       for (i = 0; i < ARRAY_SIZE (octaves); i++) {
+           if (_chord_signature_matches (notes, num_notes,
+                                         octaves[i].degrees, 1, &inversion))
+           {
+               chord_name = octaves[i].name;
+               break;
+           }
+       }
+       break;
+    case 2:
+       for (i = 0; i < ARRAY_SIZE (intervals); i++) {
+           if (_chord_signature_matches (notes, num_notes,
+                                         intervals[i].degrees, 2, &inversion))
+           {
+               chord_name = intervals[i].name;
+               break;
+           }
+       }
+       break;
+    case 3:
+       for (i = 0; i < ARRAY_SIZE (triads); i++) {
+           if (_chord_signature_matches (notes, num_notes,
+                                         triads[i].degrees, 3, &inversion))
+           {
+               chord_name = triads[i].name;
+               break;
+           }
+       }
+       break;
+    case 4:
+       for (i = 0; i < ARRAY_SIZE(sevenths); i++) {
+           if (_chord_signature_matches (notes, num_notes,
+                                         sevenths[i].degrees, 4, &inversion))
+           {
+               chord_name = sevenths[i].name;
+               break;
+           }
+       }
+       break;
     }
 
-    for (i = 0; i < ARRAY_SIZE(sevenths); i++) {
-       if (_chord_signature_matches (notes, num_notes, sevenths[i].pitches, 4))
-           chord_name = sevenths[i].name;
+    if (chord_name) {
+       if (inversion) {
+           const char *inversion_str;
+           switch (inversion) {
+           case 1:
+               inversion_str = "1st inversion";
+               break;
+           case 2:
+               inversion_str = "2nd inversion";
+               break;
+           case 3:
+               inversion_str = "3rd inversion";
+               break;
+           default:
+               fprintf (stderr, "Internal error: Unexpected inversion: %d\n",
+                        inversion);
+               exit(1);
+           }
+           chord_name = talloc_asprintf (local, "%s %s",
+                                         chord_name, inversion_str);
+       } else {
+           chord_name = talloc_strdup (local, chord_name);
+       }
+    } else {
+       chord_name = talloc_strdup (local, "Unknown chord");
     }
 
-    if (chord_name)
-       scherzo->chord = score_add_chord (scherzo->treble, chord_name);
-    else
-       scherzo->chord = score_add_chord (scherzo->treble, "Unknown or not a chord");
+    scherzo->chord = score_add_chord (scherzo->treble, chord_name);
 
 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)
+{
+    int i;
+
+    /* Do nothing if note is already in group. */
+    for (i = 0; i < group->num_notes; i++) {
+       if (group->notes[i]->pitch == note->pitch &&
+           group->notes[i]->octave == note->octave)
+       {
+           return;
+       }
+    }
+
+    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;
     int i;
 
-    if (scherzo->challenge.note)
+    if (scherzo->challenge.note) {
        staff = scherzo->challenge.staff;
-    else
+    } else if (octave >= 4) {
        staff = scherzo->treble;
+    } else {
+       staff = scherzo->bass;
+    }
 
     /* 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
@@ -628,25 +941,25 @@ _select_challenge (scherzo_t *scherzo)
 
     switch (*s) {
     case 'C':
-       pitch = SCORE_PITCH_VALUE(C, NATURAL);
+       pitch = SCORE_PITCH_C;
        break;
     case 'D':
-       pitch = SCORE_PITCH_VALUE(D, NATURAL);
+       pitch = SCORE_PITCH_D;
        break;
     case 'E':
-       pitch = SCORE_PITCH_VALUE(E, NATURAL);
+       pitch = SCORE_PITCH_E;
        break;
     case 'F':
-       pitch = SCORE_PITCH_VALUE(F, NATURAL);
+       pitch = SCORE_PITCH_F;
        break;
     case 'G':
-       pitch = SCORE_PITCH_VALUE(G, NATURAL);
+       pitch = SCORE_PITCH_G;
        break;
     case 'A':
-       pitch = SCORE_PITCH_VALUE(A, NATURAL);
+       pitch = SCORE_PITCH_A;
        break;
     case 'B':
-       pitch = SCORE_PITCH_VALUE(B, NATURAL);
+       pitch = SCORE_PITCH_B;
        break;
     default:
        fprintf (stderr, "Malformed pitch name: %s (expected 'A' - 'G')\n", s);
@@ -739,12 +1052,12 @@ 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;
@@ -754,6 +1067,19 @@ 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);
@@ -791,8 +1117,14 @@ main (int argc, char *argv[])
 
     scherzo.chord = NULL;
 
-    scherzo.num_notes_pressed = 0;
-    scherzo.notes_pressed = NULL;
+    /* Default to octave 4 and natural for computer keyboard keypresses. */
+    scherzo.keyboard_octave = 4;
+    scherzo.keyboard_accidental = SCORE_PITCH_ACCIDENTAL_NATURAL;
+
+    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. */