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)
{
+#define MAX_DEGREES 4
+ int relative_pitches[MAX_DEGREES];
int i;
- if (num_notes != num_signature_pitches)
+ assert (num_degrees <= MAX_DEGREES);
+
+ if (num_notes != num_degrees)
return 0;
+ for (i = 0; i < num_degrees; i++)
+ relative_pitches[i] = _modified_degree_to_half_steps (°rees[i]);
+
for (i = 0; i < num_notes; i++)
- if (notes[i].relative_pitch != signature_pitches[i])
+ if (notes[i].relative_pitch != relative_pitches[i])
return 0;
return 1;
num_notes = note_group->num_notes;
- struct { int pitches[1]; const char *name; } octaves[] = {
- { {0}, "Octave"}
+ struct { modified_degree_t degrees[1]; const char *name; } octaves[] = {
+ { {{0, 0}}, "Octave"}
};
- 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"}
+ 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[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[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 { int pitches[4]; const char *name; } sevenths[] = {
- { {0, 4, 8, 11}, "Augmented/major 7" },
- { {0, 4, 8, 10}, "Augmented 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, 11}, "Diminished/major 7" },
- { {0, 3, 6, 10}, "Half-diminished 7" },
- { {0, 3, 6, 9}, "Diminished 7" }
+ 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) {
switch (num_notes) {
case 1:
for (i = 0; i < ARRAY_SIZE (octaves); i++) {
- if (_chord_signature_matches (notes, num_notes, octaves[i].pitches, 1))
+ if (_chord_signature_matches (notes, num_notes,
+ octaves[i].degrees, 1))
chord_name = octaves[i].name;
}
break;
case 2:
for (i = 0; i < ARRAY_SIZE (intervals); i++) {
- if (_chord_signature_matches (notes, num_notes, intervals[i].pitches, 2))
+ if (_chord_signature_matches (notes, num_notes,
+ intervals[i].degrees, 2))
chord_name = intervals[i].name;
}
break;
case 3:
for (i = 0; i < ARRAY_SIZE (triads); i++) {
- if (_chord_signature_matches (notes, num_notes, triads[i].pitches, 3))
+ if (_chord_signature_matches (notes, num_notes,
+ triads[i].degrees, 3))
chord_name = triads[i].name;
}
break;
case 4:
for (i = 0; i < ARRAY_SIZE(sevenths); i++) {
- if (_chord_signature_matches (notes, num_notes, sevenths[i].pitches, 4))
+ if (_chord_signature_matches (notes, num_notes,
+ sevenths[i].degrees, 4))
chord_name = sevenths[i].name;
}
break;
projects / scherzo / blobdiff