mlua-pulse 0.1.0

local pulse = require("pulse")

local title = "mini-symphony"
local bpm = 92.0
local beat = 60.0 / bpm
local export_options = {
  sample_rate = 44100,
  normalize = "rms",
  target_db = -18.0,
  true_peak_db = -1.0,
  midi_velocity_gain = 2.0,
  midi_min_velocity = 0.62,
}

local function rep(value, count)
  local values = {}
  for index = 1, count do
    values[index] = value
  end
  return values
end

local function degree(scale, value)
  local unique = #scale - 1
  local zero = value - 1
  local octave = math.floor(zero / unique)
  local position = (zero % unique) + 1
  return pulse.transpose(scale[position], octave * 12)
end

local function line(scale, degrees)
  local notes = {}
  for index, value in ipairs(degrees) do
    notes[index] = degree(scale, value)
  end
  return notes
end

local function voicing(root, kind, shifts)
  local source = pulse.chord(root, kind)
  local chord = {}
  for index, shift in ipairs(shifts) do
    chord[index] = pulse.transpose(source[((index - 1) % #source) + 1], shift)
  end
  return chord
end

local d_minor = pulse.scale("D4", "minor")
local f_major = pulse.scale("F4", "ionian")
local a_phrygian = pulse.scale("A3", "phrygian")
local d_bass = pulse.scale("D2", "minor")

local exposition = pulse.phrase()
  :add(
    pulse.sequence()
      :chords({
        voicing("D3", "min7", {0, 12, 0, 12}),
        voicing("Bb2", "maj7", {0, 12, 0, 12}),
        voicing("F3", "maj7", {0, 0, 12, 12}),
        voicing("A2", "dominant7", {0, 12, 0, 12}),
      })
      :durations(rep(beat * 2.0, 4))
      :instrument("strings")
      :volume(0.58)
      :pan(-0.16)
      :velocity(0.5)
      :effect("chorus", "wide")
  )
  :add(
    pulse.sequence()
      :notes(line(d_minor, {1, 3, 5, 6, 8, 10, 8, 6, 5, 4, 3, 5, 6, 8, 10, 12}))
      :durations(rep(beat / 2.0, 16))
      :instrument("flute")
      :volume(0.36)
      :pan(0.24)
      :velocity(0.48)
      :at(beat)
      :effect("reverb", "hall")
  )
  :add(
    pulse.sequence()
      :notes(line(d_bass, {1, 5, 1, 5, 6, 3, 5, 1}))
      :durations(rep(beat, 8))
      :instrument("double_bass")
      :volume(0.64)
      :pan(-0.28)
      :velocity(0.62)
  )
  :repeat_times(2)

local development = pulse.phrase()
  :add(
    pulse.sequence()
      :chords({
        voicing("A2", "minor", {0, 12, 0}),
        voicing("G2", "minor", {0, 12, 0}),
        voicing("F2", "maj7", {0, 12, 0, 12}),
        voicing("E2", "dim", {0, 12, 0}),
      })
      :durations(rep(beat * 2.0, 4))
      :instrument("slow_strings")
      :volume(0.62)
      :pan(0.0)
      :velocity(0.56)
      :effect("reverb", "chamber")
  )
  :add(
    pulse.sequence()
      :notes(line(a_phrygian, {1, 2, 4, 5, 7, 8, 10, 8, 7, 5, 4, 2, 1, 2, 4, 5}))
      :durations(rep(beat / 2.0, 16))
      :instrument("oboe")
      :volume(0.38)
      :pan(-0.24)
      :velocity(0.48)
      :at(beat / 2.0)
      :effect("delay", { time = beat, feedback = 0.18, mix = 0.14 })
  )
  :add(
    pulse.sequence()
      :notes(line(d_bass, {5, 5, 4, 4, 3, 3, 2, 2}))
      :durations(rep(beat, 8))
      :instrument("cello")
      :volume(0.58)
      :pan(0.18)
      :velocity(0.58)
  )
  :repeat_times(2)

local fanfare = pulse.phrase()
  :add(
    pulse.sequence()
      :chords({
        voicing("F3", "maj7", {0, 0, 12, 12}),
        voicing("C3", "dominant7", {0, 0, 12, 12}),
        voicing("D3", "min7", {0, 0, 12, 12}),
        voicing("A2", "dominant7", {0, 12, 0, 12}),
      })
      :durations(rep(beat * 2.0, 4))
      :instrument("brass_section")
      :volume(0.66)
      :pan(0.08)
      :velocity(0.7)
      :effect("compressor", "gentle")
  )
  :add(
    pulse.sequence()
      :notes(line(f_major, {8, 10, 12, 13, 12, 10, 8, 6, 5, 6, 8, 10, 12, 10, 8, 5}))
      :durations(rep(beat / 2.0, 16))
      :instrument("violin")
      :volume(0.46)
      :pan(-0.16)
      :velocity(0.56)
      :effect("reverb", "plate")
  )
  :add(
    pulse.sequence()
      :notes(line(d_bass, {1, 1, 5, 5}))
      :durations(rep(beat * 2.0, 4))
      :instrument("timpani")
      :volume(0.52)
      :pan(0.0)
      :velocity(0.76)
  )
  :repeat_times(2)

local coda = pulse.phrase()
  :add(
    pulse.sequence()
      :chords({
        voicing("D3", "min7", {0, 12, 0, 12}),
        voicing("G2", "minor", {0, 12, 0}),
        voicing("A2", "dominant7", {0, 12, 0, 12}),
        voicing("D3", "minor", {0, 0, 12}),
      })
      :durations(rep(beat * 2.0, 4))
      :instrument("strings")
      :volume(0.54)
      :velocity(0.5)
  )
  :add(
    pulse.sequence()
      :notes(line(d_minor, {8, 7, 6, 5, 4, 3, 2, 1}))
      :durations(rep(beat, 8))
      :instrument("flute")
      :volume(0.32)
      :pan(0.22)
      :velocity(0.42)
  )

local song = pulse.song()
  :tempo(bpm)
  :add_phrase(exposition)
  :add_phrase(development)
  :add_phrase(fanfare)
  :add_phrase(coda)
  :master_effect("reverb", "cathedral")
  :master_effect("eq", "bright")
  :master_effect("limiter", "standard")

assert(title == "mini-symphony")
song:export_wav("output/mini-symphony.wav", export_options)
song:export_midi("output/mini-symphony.mid", export_options)