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Change timing notation

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This commit is contained in:
Michael Hayes
2011-08-31 21:15:06 +00:00
parent 5580ca8b3a
commit be813dcb55
6 changed files with 89 additions and 72 deletions
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apps/squeak2/Makefile
+1 -1
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@@ -5,7 +5,7 @@
# Definitions.
CC = avr-gcc
CFLAGS = -mmcu=atmega32u2 -Os -Wall -Wstrict-prototypes -Wextra -g -I../../drivers/avr -I../../extra -I../../drivers -I../../utils
CFLAGS = -mmcu=atmega32u2 -Os -finline -Wall -Wstrict-prototypes -Wextra -g -I../../drivers/avr -I../../extra -I../../drivers -I../../utils
OBJCOPY = avr-objcopy
SIZE = avr-size
DEL = rm
apps/squeak4/Makefile
+1 -1
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@@ -5,7 +5,7 @@
# Definitions.
CC = avr-gcc
CFLAGS = -mmcu=atmega32u2 -Os -Wall -Wstrict-prototypes -Wextra -g -I../../drivers -I../../extra -I../../drivers/avr -I../../fonts -I../../utils
CFLAGS = -mmcu=atmega32u2 -Os -finline -Wall -Wstrict-prototypes -Wextra -g -I../../drivers -I../../extra -I../../drivers/avr -I../../fonts -I../../utils
OBJCOPY = avr-objcopy
SIZE = avr-size
DEL = rm
apps/squeak4/squeak4.c
+1 -1
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@@ -51,7 +51,7 @@ void
note_play (tweeter_t tweeter, tweeter_note_t note, uint8_t velocity)
{
tinygl_clear ();
if (note != 0)
if (note != 0 && velocity != 0)
tinygl_draw_string (note_names[note % 12], tinygl_point (0, 0), 1);
tweeter_note_play (tweeter, note, velocity);
etc/Makefile
+1 -1
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@@ -50,7 +50,7 @@ docs: $(DOCMAKEFILES)
(cd $(dir $@); ../../etc/makemake.py --cc="gcc" --cflags="" --relpath --objext=-test.o --template ../../etc/Makefile.test.template . . ../../utils ../../drivers ../../drivers/test ../../extra > Makefile.test)
../%/Makefile: Makefile.template Makefile makemake.py
(cd $(dir $@); ../../etc/makemake.py --cc="avr-gcc" --cflags="-Os -mmcu=atmega32u2" --relpath --template ../../etc/Makefile.template . . ../../utils ../../fonts ../../drivers ../../drivers/avr ../../extra > Makefile)
(cd $(dir $@); ../../etc/makemake.py --cc="avr-gcc" --cflags="-Os -mmcu=atmega32u2 -finline" --relpath --template ../../etc/Makefile.template . . ../../utils ../../fonts ../../drivers ../../drivers/avr ../../extra > Makefile)
extra/mmelody.c
+76 -60
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@@ -20,62 +20,55 @@
C5? This uses numbers to indicate note duration, for example, C2
denotes a C of twice the standard duration.
For emphasis of first beat in bar, perhaps use ^ to indicate
louder, for example, C^. Similarly, to make a note quieter it
could have a v suffix. Alternatively, | bar markers could be
inserted and perhaps time signatures.
By default notes are crotchets (quarter notes) and tempos are
defined in beats per minute. If we assume 4/4 time, then each beat
has a quarter-note duration.
By default notes are quarter-notes. It is probably best to define
speed in terms of quarter-notes (beats per minute) rather than bars
per minute since this requires bars to be defined. Two bars in 4/4
could be represented by C^DEDC^BAB whereas two bars in 3/4 could be
represented by C^DEC^DE.
The note duration can be halved with a comma suffix, e.g., A,
So how should we denote note duration? We need to distinguish
between 2 identical quarter-notes (A A) played in succession and a
half-note since this sounds different.
The note duration can be extended by a half with a dot suffix, e.g., A.
We could use AA to indicate two A quarter-notes. Alternatively, we
could use AA to indicate an A half-note. However, for a whole note
we would need to indicate this with AAAA. With the latter scheme
we could separate two indentical quarter notes with a comma, for
example, A,A.
The note duration can be doubled with a slash suffix, e.g., A/
Eighth notes and triplets? *8 switches to interpreting the notes
as eighth notes. *4 switches back to quarter notes.
The note duration can be trebled with two slash suffixes, e.g., A//
(this can be continued to lengthen the note).
Rests are easy. Each space represents one rest of quarter-note
duration. Two spaces represent a half-note rest. Alternatively,
we could represent this with " /".
If there are lots of quavers (eighth notes), then the default note
duration can be switched using *8. *4 returns to quarter note timing.
From a sequencing point of view it is simpler if every symbol
represents a quarter-note rather than having variable length notes
since this alters the sequencing timing. This favours the approach
of using AA to denote a half-note.
Rests are specified with a space character. The timing modifiers ,
. and / can be used.
If I implement a simple attack/decay response then it would be
easier to use A/ for a half-note since we would interpret the / as
to keep playing the previous note without sounding it again.
Alternatively, when each new note is sounded there could be a short
delay.
<ABC> is equivalent to ABCABC
>num could indicate jump forward to label num while <num could
represent jump back to label num. Although I prefer the notation
<ABC>3 to represent playing the notes ABC in succession 3 times.
This notation could be nested, for example, <ABC<DEF>2>3.
Perhaps <ABC> denotes playing ABC indefinitely? No I prefer
a simple repeat. Use ABC: for an infinite repeat.
<ABC>3 is equivalent to ABCABCABC
ABC: performs an infinite repeat of ABC
<ABC]1DE]2FG> represents ABCDEABCFG where ]n denotes alternate
endings.
With 8 bits for the tempo (in bpm), the max tempo is 255 bpm.
This corresponds to 4.25 beats per second. If the minimum time
to release a note is 1 / 8 of a quarter note, then we need
to poll at a rate of at least 4.25 * 8 = 34 times per second.
A+ sounds an octave higher
A- sounds an octave lower
@120 sets the tempo to 120 beats per minute
This could be made a lot more flexible but the orginal
implementation had a tight memory constraint.
implementation had a tight memory constraint. Possible extensions:
* For emphasis perhaps use ^ to indicate louder, for example, C^.
Similarly, to make a note quieter it could have a v suffix.
* Use | for bar markers; these can be ignored.
* Time signatures.
* Nested loops, e.g., <AB<ABC>>
* sixteenth notes? Perhaps A,,
* Perhaps lower case for eighth notes.
*/
enum {MMELODY_SCALE_SIZE = 12};
@@ -89,22 +82,31 @@ mmelody_ticker_set (mmelody_t mmelody)
/* Notes per four minutes. */
speed = mmelody->speed * mmelody->note_fraction;
mmelody->beat_duration = mmelody->poll_rate * 60 * 4 / speed;
/* This is the duration of an eighth-note.
With note_fraction = 4, speed = 50, and poll_rate of 200 this
gives a result of 120. */
mmelody->note_ticks = mmelody->poll_rate * 60 * 2 / speed;
}
static void
mmelody_note_on (mmelody_t mmelody, mmelody_note_t note, uint8_t duration)
{
/* The duration is in terms of eighth notes. */
mmelody->play_callback (mmelody->play_callback_data, note,
mmelody->volume);
mmelody->note = note;
/* Determine ticks between sounding notes. */
mmelody->ticks2 = (mmelody->beat_duration + 8) / 16;
/* Determine ticks between sounding notes (this needs to be a
minimum of 1). */
mmelody->ticks2 = mmelody->note_ticks / 16;
if (!mmelody->ticks2)
mmelody->ticks2 = 1;
/* Determine ticks before turning the note off. */
mmelody->ticks1 = mmelody->beat_duration * duration - mmelody->ticks2;
mmelody->ticks1 = mmelody->note_ticks * duration - mmelody->ticks2;
}
@@ -148,7 +150,7 @@ mmelody_scan (mmelody_t mmelody, const char *str)
char modifier;
bool have_hash;
bool have_num;
mmelody_note_t note;
mmelody_note_t note = 0;
uint8_t duration = 1;
/* Play rest at end of melody. */
@@ -218,17 +220,6 @@ mmelody_scan (mmelody_t mmelody, const char *str)
str++;
continue;
/* Play rest. */
case ' ':
while (*str == '/')
{
duration++;
str++;
}
mmelody_note_on (mmelody, 0, duration);
return str;
break;
case '*':
if (num)
mmelody_note_fraction_set (mmelody, num);
@@ -263,11 +254,31 @@ mmelody_scan (mmelody_t mmelody, const char *str)
/* Convert note to MIDI note number. */
note += (mmelody->octave + 1) * MMELODY_SCALE_SIZE;
/* Fall through. */
case ' ':
while (*str == '/')
{
duration++;
str++;
}
if (*str == '.')
{
/* Dotted quarter note. */
duration += duration * 2;
str++;
}
else if (*str == ',')
{
/* Eighth note. */
str++;
/* What about dotted eighth notes? */
}
else
{
/* Quarter note. */
duration *= 2;
}
mmelody_note_on (mmelody, note, duration);
return str;
@@ -303,7 +314,12 @@ mmelody_play (mmelody_t mmelody, const char *str)
void
mmelody_speed_set (mmelody_t mmelody, mmelody_speed_t speed)
{
/* The duration of a beat varies with the time signature:
/* With 8 bits for the tempo (in bpm), the max tempo is 255 bpm.
This corresponds to 4.25 beats per second. If the minimum time
to release a note is 1 / 8 of a quarter note, then we need to
poll at a rate of at least 4.25 * 8 = 34 times per second.
The duration of a beat varies with the time signature:
2/2 : minum (half note)
4/4 : crotchet (quarter note)
6/8, 9/8, 12/8 : dotted crotchet (one and a half quarter notes)
@@ -365,11 +381,11 @@ mmelody_init (mmelody_obj_t *mmelody,
mmelody->play_callback = play_callback;
mmelody->play_callback_data = play_callback_data;
mmelody->volume = 100;
mmelody->note_fraction = 1;
mmelody->note = 0;
mmelody->ticks1 = 0;
mmelody->ticks2 = 0;
mmelody_speed_set (mmelody, MMELODY_SPEED_DEFAULT);
mmelody_note_fraction_set (mmelody, 4);
return mmelody;
}
extra/mmelody.h
+3 -2
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@@ -20,9 +20,10 @@ enum {MMELODY_SPEED_DEFAULT = 200};
typedef struct
{
uint16_t beat_duration;
uint16_t ticks1;
uint16_t ticks2;
uint8_t ticks2;
/* Duration of an eighth note. */
uint8_t note_ticks;
/* Pointer to current position in string. */
const char *cur;
/* Pointer to start of string. */