handle clipping
move osc&gain to the user side
This commit is contained in:
Locria Cyber
parent
7a508ad33d
commit
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ED0D424AE4406330
59
music.nim
59
music.nim
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@ -1,7 +1,7 @@
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import musiclib, std/math
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import musiclib, std/[math, sugar]
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# Number of times to sample each second
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let bitrate = 44100
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const bitrate = 44100
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func osc_piano*(f, t: float): float =
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## Returns the intensity of a tone of frequency f sampled at time t
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@ -20,15 +20,28 @@ func osc_piano*(f, t: float): float =
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Y *= 1 + 16 * t * math.exp(-6 * t)
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Y
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func osc_pulse*(f,t:float):float =
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let width = (1.0 / f) / 2
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let phase: float = t mod (width * 2)
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if phase < width: 1.0 else: -1.0
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func freq*(octave, step: float): float =
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## Returns the frequency of a note
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55 * pow(2, (octave + step / 12 - 1))
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func p*(len, octave, step, vol: float = 1): Note =
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var osc: OscFn = (f, t: float) => 0.0
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proc p*(len, octave, step, vol: float = 1): Note =
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## Note helper constructor
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let osc: OscFn = osc_piano
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(len, freq(octave, step), vol, osc)
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#------- song region -------
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const GAIN_NORMAL = 0.24
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osc = (f, t: float) => osc_piano(f, t) * GAIN_NORMAL
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let intro = [
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p(1,3,3),
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p(1,3,7),
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@ -51,6 +64,8 @@ let intro = [
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p(8,3,7),
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]
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# osc = osc_pulse
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let melody = [
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p(1,3,3),
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p(1,3,7),
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@ -119,17 +134,6 @@ let melody = [
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p(2,4,10),
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]
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let bass = [
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p(1,1,3),
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p(1,1,10),
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p(1,1,1),
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p(1,1,8),
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p(1,1,3),
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p(1,2,3),
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p(1,1,1),
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p(1,1,10),
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]
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let melody2 = [
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p(1,0,0),
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p(1,5,10),
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@ -273,6 +277,19 @@ let outro = [
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p(16,3,7,2),
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]
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osc = (f, t: float) => osc_piano(f, t) * GAIN_NORMAL * 1.5
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let bass = [
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p(1,1,3),
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p(1,1,10),
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p(1,1,1),
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p(1,1,8),
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p(1,1,3),
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p(1,2,3),
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p(1,1,1),
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p(1,1,10),
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]
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from std/algorithm import sort
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# Process all lists of notes
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@ -280,16 +297,16 @@ var music: seq[ProcessedNote] = @[]
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music.process(intro, 0, 4)
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music.process(melody, 8, 4)
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music.process(melody, 24, 4)
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music.process(bass, 24, gain=1.5)
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music.process(bass, 32, gain=1.5)
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music.process(bass, 24)
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music.process(bass, 32)
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music.process(melody, 40, 4)
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music.process(melody2, 40, 4)
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music.process(bass, 40, gain=1.5)
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music.process(bass, 48, gain=1.5)
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music.process(bass, 40)
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music.process(bass, 48)
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music.process(melody, 56, 4)
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music.process(melody3, 56, 4)
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music.process(bass, 56, gain=1.5)
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music.process(bass, 64, gain=1.5)
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music.process(bass, 56)
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music.process(bass, 64)
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music.process(outro, 72, 4)
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music.sortByStart()
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20
musiclib.nim
20
musiclib.nim
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@ -16,12 +16,9 @@ type
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vol: float
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osc: OscFn
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## give some seconds for the note to fade out
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const HACK_DROPOFF_DELAY = 2.0
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const HACK_LONGEST_NOTE = 16.0
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func process*(music: var seq[ProcessedNote], notes: openArray[Note]; start_init: float, speed: float=1, gain:float = 1) =
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func process*(music: var seq[ProcessedNote], notes: openArray[Note]; start_init: float, speed: float=1) =
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## Adds a list of notes to the music list
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##
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## `notes` sequence of notes with no rests in between
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@ -32,7 +29,7 @@ func process*(music: var seq[ProcessedNote], notes: openArray[Note]; start_init:
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assert note.len <= HACK_LONGEST_NOTE, &"note too long: {note.len}"
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start = t
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let stop = t + note.len / speed
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music &= (start, stop, note.freq, note.vol * gain, note.osc)
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music &= (start, stop, note.freq, note.vol, note.osc)
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t = stop
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func sortByStart*(music: var seq[ProcessedNote]) =
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@ -45,7 +42,7 @@ func bisect(music: openArray[ProcessedNote], x: float): int =
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music.lowerBound(x, (m, key) => cmp(m.start, key))
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const GAIN_BIAS: float = pow(2.0, 28.0)
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const GAIN_BIAS: float = pow(2.0, 31.0)
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proc at*(music: openArray[ProcessedNote], t: float): int32 =
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## Returns the total intensity of music sampled at time t
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@ -59,10 +56,13 @@ proc at*(music: openArray[ProcessedNote], t: float): int32 =
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while i >= 0:
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let m = music[i]
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assert m.start <= t
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if m.stop + HACK_DROPOFF_DELAY >= t:
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ret += m.vol * m.osc(m.freq, t - m.start)
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if m.start + HACK_LONGEST_NOTE + HACK_DROPOFF_DELAY < t:
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if m.start + HACK_LONGEST_NOTE < t:
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break
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else:
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ret += m.vol * m.osc(m.freq, t - m.start)
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i -= 1
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int32(ret * GAIN_BIAS)
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ret *= GAIN_BIAS
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# clip sample
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clamp(ret, int32.low.float..int32.high.float).int32
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