Module: Cyclotone::Backends::MIDIMessageSupport

Included in:
MIDIBackend, MIDIFileBackend
Defined in:
lib/cyclotone/backends/midi_message_support.rb

Constant Summary collapse

SUPPORTED_NOTE_CONTROLS = 
%i[
  note channel velocity gain velocity_scale release_velocity release_velocity_scale sustain sustain_cycles fractional_notes
].freeze
SUPPORTED_CC_CONTROLS = 
%i[
  cc channel cc_scale controller_scale
].freeze
UNSUPPORTED_CONTROL_POLICIES = 
%i[ignore error].freeze
FRACTIONAL_NOTE_POLICIES = 
%i[floor round error].freeze

Instance Method Summary collapse

Instance Method Details

#messages_for(event, cps: nil) ⇒ Object 



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# File 'lib/cyclotone/backends/midi_message_support.rb', line 15

def messages_for(event, cps: nil)
  values = event.value.is_a?(Hash) ? event.value : { note: event.value }
  if values.key?(:cc)
    validate_unsupported_controls!(values, SUPPORTED_CC_CONTROLS)
    return control_change_messages(values)
  end

  notes = Array(values[:note])
  return [] if notes.empty? || notes.all?(&:nil?)

  validate_unsupported_controls!(values, SUPPORTED_NOTE_CONTROLS)

  active_channel = normalize_channel(values[:channel] || channel)
  sustain = [extract_sustain(values, event, cps), 0.0].max
  velocity_scale = values[:velocity_scale]
  attack_velocity = normalize_velocity(values[:velocity] || values[:gain] || 1.0, scale: velocity_scale)
  release_velocity = normalize_velocity(
    values.fetch(:release_velocity, 0),
    scale: values.fetch(:release_velocity_scale, velocity_scale)
  )

  notes.compact.flat_map do |note|
    normalized_note = normalize_note(note, policy: values.fetch(:fractional_notes, fractional_note_policy))

    [
      {
        type: :note_on,
        channel: active_channel,
        note: normalized_note,
        velocity: attack_velocity
      },
      {
        type: :note_off,
        channel: active_channel,
        note: normalized_note,
        velocity: release_velocity,
        delay: sustain
      }
    ]
  end
end