Sail with me into the Pi - Part 3

sail.rb

module NumberMethods
  def beat; self; end
  def beats; self; end
  def triplet; self.to_f / 3; end
  def triplets; self.to_f / 3; end
  def bar; self * 4; end
  def bars; self * 4; end
end
::Numeric.send(:include, NumberMethods)

@synths = {
  vamp: :tri,
  bass: :saw,
  riff: :prophet
}

def vamp(notes, length)
  use_synth @synths[:vamp]
  length.times do
    with_fx :reverb, damp: 0.8, room: 0.4 do
      play notes, attack: 0.01, sustain: 1.triplets, release: 1.triplet
      sleep 1.beat
    end
  end
end

def bass_hit(root)
  use_synth @synths[:bass]
  root_note = note(root)
  notes = [root_note, (root_note + 7), (root_note + 12)]
  play notes, :sustain => 2.beats, :release => 2.triplets
  sleep 2.beats
end

def riff_pluck(note, length)
  use_synth @synths[:riff]
  play note, attack: 0, decay: 0, sustain: 0, release: 1.triplet
  sleep length
end

def riff_triplet(note)
  3.times { riff_pluck(note, 1.triplet) }
end

def riff_Eb
  sleep 2.beats
  riff_triplet(:Eb4)
  riff_triplet(:Gb4)
  riff_pluck(:Ab4, 1.beat)
  riff_pluck(:Bb4, 1.beat)
  riff_pluck(:Ab4, 2.triplets)
  riff_pluck(:Gb4, 1.triplet)
  riff_pluck(:Eb4, 1.beat)
end

def riff_Db
  sleep 2.beats
  riff_triplet(:Db4)
  riff_triplet(:Eb4)
  riff_pluck(:Bb3, 1.beat)
  riff_pluck(:Eb4, 1.beat)
  riff_pluck(:Gb4, 2.triplets)
  riff_pluck(:Eb4, 1.triplet)
  riff_pluck(:Db4, 1.beat)
end

def short_riff_Gb
  sleep 2.beats
  riff_triplet(:Bb4)
  riff_triplet(:Db5)
end

def short_riff_Db
  sleep 2.beats
  riff_triplet(:Eb5)
  riff_pluck(:Gb5, 1.beat)
end

#---------------------------

def bass_loop
  in_thread do
    bass_hit(:Eb2)
    sleep 6.beats
    bass_hit(:Eb2)
    sleep 6.beats
    bass_hit(:Db2)
    sleep 6.beats
    bass_hit(:Gb2)
    sleep 2.beats
    bass_hit(:Db2)
    sleep 2.beats
  end
end

def vamp_loop
  in_thread do
    vamp([:eb4, :gb4, :eb3], 6)
    vamp([:eb4, :ab4, :eb3], 2)
    vamp([:eb4, :gb4, :eb3], 6)
    vamp([:eb4, :ab4, :eb3], 2)
    vamp([:db4, :f4,  :db3], 8)
    vamp([:gb4, :db5, :gb3], 4)
    vamp([:db4, :f4,  :db3], 4)
  end
end

def riff_loop
  in_thread do
    2.times { riff_Eb }
    riff_Db
    short_riff_Gb
    short_riff_Db
  end
end

use_bpm 120

vamp([:eb4, :ab4], 2)
vamp_loop
wait 8.bars
bass_loop
vamp_loop
riff_loop