Ruby SDL playback (as used in CMG)

gistfile1.rb

# I initialise on L19-22
# let $SAMPLERATE be 48000; I'd like to do this more dynamically, eventually
SDL.init(SDL::INIT_AUDIO)
SDL::Mixer.open($SAMPLERATE, SDL::Mixer::DEFAULT_FORMAT, 2, 8192)
SDL::Mixer.allocate_channels(128)

# Inside the class Channel, I play audio on L68 (cherrypicking salient lines).
# Typically, there exist 64 Channels.
class Channel
  attr_accessor :sdl, :num
  
  # L58-92
  def fire_audio()
    if @sdl
      SDL::Mixer.play_channel(@num, @sdl, 0)
    end
  end

  # L95-107
  def load_file(file)
    @sdl = SDL::Mixer::Wave.load(file)
  end
  
  # L110-119
  def initialize(number)
    @num = number
  end
end

# I use Gdk/Gtk bindings to run 'fire_audio'; (cherrypicked from L146)
# let win be an instance of Gtk::Window
# let $key_table be an array of Gdk::Keyval names
# let $channel be an array of 64 Channel instances
win.signal_connect("key-press-event") do |w, e|
  name = Gdk::Keyval.to_name(e.keyval)
  if i = $key_table.index(name)
    $channel[i].fire_audio 
  end
end