Merge pull request 'Nim port' (#1) from iacore/Lambeat:main into main Reviewed-on: https://git.exozy.me/a/Lambeat/pulls/1

Changes

4 changed files (+424/-0)

• .gitignore (new)
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    + /music + /music.s32
• README.md
  • @@ -5,3 +5,10 @@ ## Get started
    First, install [Sox](https://sox.sourceforge.net/) and clone this repo. Write some music in `music.scm`. Enjoy your music with `guile --fresh-auto-compile lambeat.scm | play -r 8000 -t s16 -`! For the Python version, use `pypy3 music.py | play -r 44100 -t s32 -` to listen and `pypy3 music.py | sox -r 44100 -t s32 - example.ogg` to save to a file. + + For the nim version + ``` + nim c --mm:orc -d:release music.nim + ./music > music.s32 + play -r 44100 -t s32 music.s32 + ```
• music.nim (new)
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    + import musiclib, std/[math, sugar] + + # Number of times to sample each second + const bitrate = 44100 + + func osc_weird_pluck*(f, t: float): float = + # I got this as a bug + let w = 2 * PI * f + let wxt = w * t + let exp_swxt = math.exp(-0.001 * wxt) + let y0 = 0.6 * math.sin(wxt) + let y1 = 0.2 * math.sin(2 * wxt) + let y2 = 0.05 * math.sin(3 * wxt) + let y3 = (y0 + y1 + y2) * exp_swxt + let y4 = (1+y3)*y3*y3 # this line is different + y4 * (1 + 16 * t * math.exp(-6 * t)) + + func osc_piano*(f, t: float): float = + ## Returns the intensity of a tone of frequency f sampled at time t + ## t starts at 0 (note start) + # https://dsp.stackexchange.com/questions/46598/mathematical-equation-for-the-sound-wave-that-a-piano-makes + # https://youtu.be/ogFAHvYatWs?t=254 + # return int(2**13*(1+square(t, 440*2**(math.floor(5*t)/12)))) + # Y = sum([math.sin(2 * i * math.pi * t * f) * math.exp(-0.0004 * 2 * math.pi * t * f) / 2**i for i in range(1, 4)]) + # Y += Y * Y * Y + # Y *= 1 + 16 * t * math.exp(-6 * t) + let w = 2 * PI * f + let ewt = math.exp(-0.001 * w * t) + var Y = 0.6 * math.sin(w * t) * ewt + + 0.2 * math.sin(2 * w * t) * ewt + + 0.05 * math.sin(3 * w * t) * ewt + + let Y2 = Y * (Y * Y + 1) + Y2 * (1 + 16 * t * math.exp(-6 * t)) + + func osc_pulse*(f, t: float, phasedrift: float = 0.0): float = + let doublewidth = 1.0 / f + let width = doublewidth / 2 + let phase: float = (t + doublewidth * phasedrift) mod doublewidth + if phase < width: 1.0 else: -1.0 + + func osc_saw*(f,t:float, phasedrift: float = 0.0):float = + let doublewidth = 1.0 / f + let width = doublewidth / 2 + let phase: float = (t + doublewidth * phasedrift) mod doublewidth + if phase < width: + -1.0 + 2.0 * phase / width + else: + 1.0 - 2.0 * (phase - width) / (1.0 - width) + + func freq*(octave, step: float): float = + ## Returns the frequency of a note + 55 * pow(2, (octave + step / 12 - 1)) + + var osc: OscFn = (f, t: float) => 0.0 + + proc p*(len, octave, step, vol: float = 1): Note = + ## Note helper constructor + (len, freq(octave, step), vol, osc) + + #------- song region ------- + + const GAIN_NORMAL = 0.22 + + osc = (f, t: float) => osc_piano(f, t) * GAIN_NORMAL + + let intro = [ + p(1, 3, 3), + p(1, 3, 7), + p(1, 3, 10), + p(6, 4, 2), + + p(1, 3, 1), + p(1, 3, 5), + p(1, 3, 8), + p(3, 4, 0), + + p(1, 2, 11), + p(1, 3, 3), + p(1, 3, 6), + p(3, 3, 10), + + p(1, 2, 8), + p(1, 3, 0), + p(1, 3, 3), + p(8, 3, 7), + ] + + let outro = [ + p(1, 3, 3), + p(1, 3, 7), + p(1, 3, 10), + p(1, 4, 2), + p(1, 4, 3), + p(1, 4, 7), + p(2, 4, 8), + + p(1, 3, 1), + p(1, 3, 5), + p(1, 3, 8), + p(1, 4, 0), + p(1, 4, 1), + p(1, 4, 5), + p(2, 4, 8), + + p(1, 2, 11), + p(1, 3, 3), + p(1, 3, 6), + p(1, 3, 10), + p(1.5, 3, 11), + p(1.5, 4, 3), + p(3, 4, 8), + + p(1.5, 2, 8), + p(1.5, 3, 0), + p(2, 3, 3), + p(16, 3, 7, 2), + ] + + let melody = [ + p(1, 3, 3), + p(1, 3, 7), + p(1, 3, 10), + p(1, 4, 2), + p(1, 4, 3), + p(1, 4, 7), + p(2, 4, 8), + + p(1, 3, 1), + p(1, 3, 5), + p(1, 3, 8), + p(1, 4, 0), + p(1, 4, 1), + p(1, 4, 5), + p(2, 4, 8), + + p(1, 3, 3), + p(1, 3, 7), + p(1, 3, 10), + p(1, 4, 2), + p(1, 4, 3), + p(1, 4, 10), + p(2, 4, 3), + + p(1, 3, 1), + p(1, 3, 5), + p(1, 3, 8), + p(1, 4, 0), + p(1, 4, 10), + p(1, 4, 8), + p(2, 4, 10), + + + p(1, 3, 3), + p(1, 3, 7), + p(1, 3, 10), + p(1, 4, 2), + p(1, 4, 3), + p(1, 4, 7), + p(2, 4, 8), + + p(1, 3, 1), + p(1, 3, 5), + p(1, 3, 8), + p(1, 4, 0), + p(1, 4, 1), + p(1, 4, 5), + p(2, 4, 1), + + p(1, 3, 3), + p(1, 3, 7), + p(1, 3, 10), + p(1, 4, 2), + p(1, 4, 3), + p(1, 4, 10), + p(1, 4, 8), + p(1, 4, 7), + + p(1, 3, 1), + p(1, 3, 5), + p(1, 3, 8), + p(1, 4, 0), + p(1, 4, 10), + p(1, 4, 8), + p(2, 4, 10), + ] + + osc = (f, t: float) => osc_weird_pluck(f, t) * GAIN_NORMAL + + let melody2 = [ + p(1, 0, 0), + p(1, 5, 10), + p(1, 5, 8), + p(1, 5, 7), + p(1, 5, 8), + p(3, 5, 7, 2), + + p(1, 5, 3), + p(1, 4, 10), + p(6, 5, 1, 2), + + p(1/2, 5, 0, 2), + p(1/2, 5, 1, 2), + p(3, 5, 3, 2), + p(1/2, 5, 10, 2), + p(7/2, 5, 3, 2), + + p(8, 0, 0), + + p(1, 0, 0), + p(1, 5, 3), + p(1, 5, 10), + p(1, 5, 10), + p(4/3, 5, 10), + p(4/3, 5, 8), + p(4/3, 5, 7), + + p(1, 0, 0), + p(1, 5, 1), + p(1, 5, 8), + p(1, 5, 8), + p(4/3, 5, 8), + p(4/3, 5, 8), + p(4/3, 5, 10), + + p(8, 0, 0), + + p(1, 0, 0), + p(5, 5, 3, 2), + p(2, 5, 10, 2), + ] + + let melody3 = [ + p(1, 0, 0), + p(1, 5, 10), + p(1/2, 5, 8, 2/3), + p(1/2, 5, 7, 2/3), + p(1/4, 5, 8, 1/2), + p(1/4, 5, 7, 1/2), + p(1/4, 5, 8, 1/2), + p(1/4, 5, 7, 1/2), + p(1, 5, 8), + p(3, 5, 7, 2), + + p(1, 5, 3), + p(1, 4, 10), + p(1, 5, 1), + p(5, 5, 7, 2), + + p(1/2, 5, 7), + p(1/2, 5, 10), + p(1/4, 5, 7), + p(1/4, 5, 10), + p(1/4, 5, 7), + p(1/4, 5, 10), + p(1, 6, 3), + p(2, 5, 3, 2), + p(1/2, 6, 3), + p(5/2, 5, 3, 2), + + p(1/2, 5, 10), + p(1/2, 5, 8), + p(1/2, 5, 7), + p(1/2, 5, 8), + p(1/2, 5, 7), + p(1/2, 5, 3), + p(1/2, 4, 10), + p(1/2, 5, 1), + p(1/2, 5, 0), + p(1/2, 4, 10), + p(1/2, 4, 8), + p(1/2, 4, 10), + p(1/2, 5, 3), + p(1/2, 5, 7), + p(1/2, 5, 3), + p(1/2, 5, 10), + + p(4/3, 5, 7), + p(4/3, 6, 3), + p(4/3, 6, 3), + p(4/3, 6, 2), + p(4/3, 5, 10), + p(4/3, 5, 7), + + p(3, 5, 5), + p(2, 5, 7), + p(2, 5, 8), + p(1, 6, 1), + + p(1, 5, 3), + p(1, 5, 5), + p(2, 5, 7), + p(1, 5, 3), + p(1, 5, 8), + p(2, 5, 10), + + p(3/2, 6, 0), + p(3/2, 6, 1), + p(5, 6, 3, 2), + ] + + # clip length to 1 second + osc = (f, t: float) => (if t > 1: 0.0 else: + (osc_saw(f, t) * GAIN_NORMAL * 0.06) + (osc_pulse(f, t) * GAIN_NORMAL * 0.3)) + + let bass = [ + p(1, 1, 3), + p(1, 1, 10), + p(1, 1, 1), + p(1, 1, 8), + p(1, 1, 3), + p(1, 2, 3), + p(1, 1, 1), + p(1, 1, 10), + ] + + from std/algorithm import sort + + # Process all lists of notes + var music: seq[ProcessedNote] = @[] + music.process(intro, 0, 4) + music.process(melody, 8, 4) + music.process(melody, 24, 4) + music.process(bass, 24) + music.process(bass, 32) + music.process(melody, 40, 4) + music.process(melody2, 40, 4) + music.process(bass, 40) + music.process(bass, 48) + music.process(melody, 56, 4) + music.process(melody3, 56, 4) + music.process(bass, 56) + music.process(bass, 64) + music.process(outro, 72, 4) + music.sortByStart() + + # Print out music encoded in s16 to standard output + for i in (0 * bitrate ..< 84 * bitrate): + let bytes = cast[array[4, uint8]](music.at(i / bitrate)) + doAssert 4 == stdout.writeBytes(bytes, 0, 4)
• musiclib.nim (new)
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    + import std/[algorithm, math, sugar, strformat, logging] + + type + OscFn* = proc (f: float, t: float): float + + Note* = tuple + len: float ## seconds + freq: float + vol: float + osc: OscFn + + ProcessedNote* = tuple + start: float ## absolute time in seconds + stop: float ## absolute time in seconds + freq: float + vol: float + osc: OscFn + + const HACK_LONGEST_NOTE = 16.0 + + func process*(music: var seq[ProcessedNote], notes: openArray[Note]; start_init: float, speed: float=1) = + ## Adds a list of notes to the music list + ## + ## `notes` sequence of notes with no rests in between + var start = start_init + var t = start + for note in notes: + assert note.len >= 0.0 + assert note.len <= HACK_LONGEST_NOTE, &"note too long: {note.len}" + start = t + let stop = t + note.len / speed + music &= (start, stop, note.freq, note.vol, note.osc) + t = stop + + func sortByStart*(music: var seq[ProcessedNote]) = + music.sort((a, b) => cmp(a.start, b.start)) + + func bisect(music: openArray[ProcessedNote], x: float): int = + ## Return the index where to insert item `x` in list `music` + ## + ## assumes `music` is sorted by `.start` + + music.lowerBound(x, (m, key) => cmp(m.start, key)) + + const GAIN_BIAS: float = pow(2.0, 31.0) + + proc at*(music: openArray[ProcessedNote], t: float): int32 = + ## Returns the total intensity of music sampled at time t + ## + ## assumes `music` is sorted by `.start` + + var i: int = music.bisect(t) - 1 + + var ret: float = 0 + + while i >= 0: + let m = music[i] + assert m.start <= t + if m.start + HACK_LONGEST_NOTE < t: + break + else: + ret += m.vol * m.osc(m.freq, t - m.start) + i -= 1 + + ret *= GAIN_BIAS + + # clip sample + if ret >= int32.high.float: + warn(&"audio clipping at t={t}") + int32.high + elif ret <= int32.low.float: + warn(&"audio clipping at t={t}") + int32.low + else: + int32(ret)