Add nim impl

Changes

4 changed files (+349/-0)

• .gitignore (new)
  • @@ -0,0 +1,1 @@
    + /music
• 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)
  • @@ -0,0 +1,273 @@
    + import musiclib + + # Number of times to sample each second + let bitrate = 44100 + + let intro = [ + n(1,3,3), + n(1,3,7), + n(1,3,10), + n(6,4,2), + + n(1,3,1), + n(1,3,5), + n(1,3,8), + n(3,4,0), + + n(1,2,11), + n(1,3,3), + n(1,3,6), + n(3,3,10), + + n(1,2,8), + n(1,3,0), + n(1,3,3), + n(8,3,7), + ] + + let melody = [ + n(1,3,3), + n(1,3,7), + n(1,3,10), + n(1,4,2), + n(1,4,3), + n(1,4,7), + n(2,4,8), + + n(1,3,1), + n(1,3,5), + n(1,3,8), + n(1,4,0), + n(1,4,1), + n(1,4,5), + n(2,4,8), + + n(1,3,3), + n(1,3,7), + n(1,3,10), + n(1,4,2), + n(1,4,3), + n(1,4,10), + n(2,4,3), + + n(1,3,1), + n(1,3,5), + n(1,3,8), + n(1,4,0), + n(1,4,10), + n(1,4,8), + n(2,4,10), + + + n(1,3,3), + n(1,3,7), + n(1,3,10), + n(1,4,2), + n(1,4,3), + n(1,4,7), + n(2,4,8), + + n(1,3,1), + n(1,3,5), + n(1,3,8), + n(1,4,0), + n(1,4,1), + n(1,4,5), + n(2,4,1), + + n(1,3,3), + n(1,3,7), + n(1,3,10), + n(1,4,2), + n(1,4,3), + n(1,4,10), + n(1,4,8), + n(1,4,7), + + n(1,3,1), + n(1,3,5), + n(1,3,8), + n(1,4,0), + n(1,4,10), + n(1,4,8), + n(2,4,10), + ] + + let bass = [ + n(1,1,3), + n(1,1,10), + n(1,1,1), + n(1,1,8), + n(1,1,3), + n(1,2,3), + n(1,1,1), + n(1,1,10), + ] + + let melody2 = [ + n(1,0,0), + n(1,5,10), + n(1,5,8), + n(1,5,7), + n(1,5,8), + n(3,5,7,2), + + n(1,5,3), + n(1,4,10), + n(6,5,1,2), + + n(1/2,5,0,2), + n(1/2,5,1,2), + n(3,5,3,2), + n(1/2,5,10,2), + n(7/2,5,3,2), + + n(8,0,0), + + n(1,0,0), + n(1,5,3), + n(1,5,10), + n(1,5,10), + n(4/3,5,10), + n(4/3,5,8), + n(4/3,5,7), + + n(1,0,0), + n(1,5,1), + n(1,5,8), + n(1,5,8), + n(4/3,5,8), + n(4/3,5,8), + n(4/3,5,10), + + n(8,0,0), + + n(1,0,0), + n(5,5,3,2), + n(2,5,10,2), + ] + + let melody3 = [ + n(1,0,0), + n(1,5,10), + n(1/2,5,8,2/3), + n(1/2,5,7,2/3), + n(1/4,5,8,1/2), + n(1/4,5,7,1/2), + n(1/4,5,8,1/2), + n(1/4,5,7,1/2), + n(1,5,8), + n(3,5,7,2), + + n(1,5,3), + n(1,4,10), + n(1,5,1), + n(5,5,7,2), + + n(1/2,5,7), + n(1/2,5,10), + n(1/4,5,7), + n(1/4,5,10), + n(1/4,5,7), + n(1/4,5,10), + n(1,6,3), + n(2,5,3,2), + n(1/2,6,3), + n(5/2,5,3,2), + + n(1/2,5,10), + n(1/2,5,8), + n(1/2,5,7), + n(1/2,5,8), + n(1/2,5,7), + n(1/2,5,3), + n(1/2,4,10), + n(1/2,5,1), + n(1/2,5,0), + n(1/2,4,10), + n(1/2,4,8), + n(1/2,4,10), + n(1/2,5,3), + n(1/2,5,7), + n(1/2,5,3), + n(1/2,5,10), + + n(4/3,5,7), + n(4/3,6,3), + n(4/3,6,3), + n(4/3,6,2), + n(4/3,5,10), + n(4/3,5,7), + + n(3,5,5), + n(2,5,7), + n(2,5,8), + n(1,6,1), + + n(1,5,3), + n(1,5,5), + n(2,5,7), + n(1,5,3), + n(1,5,8), + n(2,5,10), + + n(3/2,6,0), + n(3/2,6,1), + n(5,6,3,2), + ] + + let outro = [ + n(1,3,3), + n(1,3,7), + n(1,3,10), + n(1,4,2), + n(1,4,3), + n(1,4,7), + n(2,4,8), + + n(1,3,1), + n(1,3,5), + n(1,3,8), + n(1,4,0), + n(1,4,1), + n(1,4,5), + n(2,4,8), + + n(1,2,11), + n(1,3,3), + n(1,3,6), + n(1,3,10), + n(1.5,3,11), + n(1.5,4,3), + n(3,4,8), + + n(1.5,2,8), + n(1.5,3,0), + n(2,3,3), + n(16,3,7,2), + ] + + 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, gain=1.5) + music.process(bass, 32, gain=1.5) + music.process(melody, 40, 4) + music.process(melody2, 40, 4) + music.process(bass, 40, gain=1.5) + music.process(bass, 48, gain=1.5) + music.process(melody, 56, 4) + music.process(melody3, 56, 4) + music.process(bass, 56, gain=1.5) + music.process(bass, 64, gain=1.5) + music.process(outro, 72, 4) + music.sort() + + # 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)
  • @@ -0,0 +1,68 @@
    + import std/[algorithm, math, sugar] + + type Note* = tuple + len: float + octave: float + step: float + vol: float + + func n*(a, b, c, d: float = 1): Note = + (a, b, c, d) + + type ProcessedNote* = tuple + start: float + `end`: float + octave: float + step: float + vol: float + + func process*(music: var seq[ProcessedNote], notes: openArray[Note]; m_start: float, speed: float=1, gain:float = 1) = + ## Adds a list of notes to the music list + var start = m_start + var t = start + for note in notes: + let vol = note[3] + start = min(t, t + note[0] / speed) + let `end` = max(t, t + note[0] / speed) + music &= ((start, `end`, note[1], note[2], vol * gain)) + t = `end` + + func bisect(music: openArray[ProcessedNote], x: (float, float)): int = + ## Return the index where to insert item `x` in list `music`, assuming `music` is sorted. + music.lowerBound(x, (m, key) => cmp((m[0], m[1]), key)) + + + func freq(octave, step: float): float = + ## Returns the frequency of a note + 55 * pow(2, (octave + step / 12 - 1)) + + func tone(f, t: float): float = + ## Returns the intensity of a tone of frequency f sampled at time t + # 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 + var Y = 0.6 * math.sin(w * t) * math.exp(-0.001 * w * t) + Y += 0.2 * math.sin(2 * w * t) * math.exp(-0.001 * w * t) + Y += 0.05 * math.sin(3 * w * t) * math.exp(-0.001 * w * t) + Y += Y * Y * Y + Y *= 1 + 16 * t * math.exp(-6 * t) + Y + + const bias: float = pow(2.0, 28.0) + func at*(music: openArray[ProcessedNote], t: float): int32 = + ## Returns the total intensity of music sampled at time t + let i: int = music.bisect((t, pow(2.0, 31.0))) + # This is actually pretty efficient ngl + # Because people usually don't have that many overlapping notes + var ret: float = 0 + # this `32` is flaky + # maybe some notes are longer? + for j in (max(i - 32, 0) ..< i): + let m = music[j] + if m[0] + m[1] > t: + ret += m[4] * tone(freq(m[2], m[3]), t - m[0]) + int32(ret * bias)