Playing ASCII Drum Tabs with Sonic Pi

drum_tab_player.rb

# Transposed tab array and changed type to ring to play nicely in live_loop

# Playing ASCII drum tabs with Sonic Pi

# Ruby is an awesome language for String manipulation.
# Lets use that fact to play some drums!

# Tab for the Amen break taken from Wikipedia
# http://en.wikipedia.org/wiki/Amen_break

# Note that %Q{ ... } is just another way
# to define a string in Ruby
amen_tab = %Q{
  C |----------------|----------------|----------------|----------x-----|
  R |x-x-x-x-x-x-x-x-|x-x-x-x-x-x-x-x-|x-x-x-x-x-x-x-x-|x-x-x-x-x---x-x-|
  S |----o--o-o--o--o|----o--o-o--o--o|----o--o-o----o-|-o--o--o-o----o-|
  B |o-o-------oo----|o-o-------oo----|o-o-------o-----|--oo------o-----|
}

# This is a random tab for the drum intro to "Cold Sweat" by James Brown
cold_sweat_tab = %Q{
  C |----------o-----|----------o-----|----------o-----|----------o-----|
  hh|x---x---x---x---|x---x---x---x---|x---x---x---x---|x---x---x---x---|
  S |----o--g------o-|-o--o--g----o---|----o--g------o-|-o--o--g----o---|
  B |o---------o-----|--oo----o-o-----|o---------o-----|--oo----o-o-----|
}

use_bpm 140.0 # tempo of the sampled break

# reduce to just essential characters
# in this case 'x', 'o', 'g', - (hyphen) and line break
drum_lines = cold_sweat_tab.strip.gsub!(/[^\-xog\n]/, '')

tab = drum_lines.split(/\n+/).map {|line|
  line.chars.map { |c|
    (c == 'x' || c == 'o' || c == 'g') ? true : false
  }
}.transpose.ring

# We've turned our text into an array of arrays
tab.each {|row| puts row }

define :beats do |crash, ride, snare, bass|
  sample :drum_splash_hard if crash
  sample :drum_cymbal_closed if ride
  sample :drum_snare_hard if snare
  sample :drum_heavy_kick if bass
end

# We get the number of beats
tab_length = tab.first.length

live_loop :test do
  beats *tab.tick
  sleep 0.25
end