Class: Musicality::DrumPattern

Inherits:
Object
  • Object
show all
Defined in:
lib/musicality/composition/sequencing/drum_machine/drum_pattern.rb

Constant Summary collapse

DRUM_PART_PITCHES = 
{
  DrumParts::BASS_DRUM => Pitches::G1,
  DrumParts::SNARE_DRUM => Pitches::G3,
  DrumParts::HI_TOM => Pitches::D3,
  DrumParts::MED_TOM => Pitches::B2,
  DrumParts::LOW_TOM => Pitches::G2,
}
DUMMY_PITCH = 
Pitches::C4

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(duration, part_portions) ⇒ DrumPattern

Returns a new instance of DrumPattern.



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# File 'lib/musicality/composition/sequencing/drum_machine/drum_pattern.rb', line 15

def initialize duration, part_portions
  @duration = duration

  non_drumpart_names = part_portions.select do |part_name|
    !DRUM_PARTS.include?(part_name)
  end
  if non_drumpart_names.any?
    raise ArgumentError, "Part names used that are not drum parts: #{non_drumpart_names.inspect}"
  end

  accent_offsets = if part_portions.has_key?(DrumParts::ACCENT)
    DrumPattern.determine_accent_offsets(
      part_portions.delete(DrumParts::ACCENT).to_rhythm_class.to_rhythm(duration))
  else
    []
  end

  @part_notes = Hash[ part_portions.map do |part_name, portions|
    pitch = DRUM_PART_PITCHES[part_name] || DUMMY_PITCH
    notes = portions.to_rhythm_class.to_rhythm(duration).to_notes(pitch)
    DrumPattern.apply_accents(notes, accent_offsets)
    [ part_name, notes ]
  end ]
end

Instance Attribute Details

#duration ⇒ Object (readonly)

Returns the value of attribute duration.



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# File 'lib/musicality/composition/sequencing/drum_machine/drum_pattern.rb', line 4

def duration
  @duration
end

#part_notes ⇒ Object (readonly)

Returns the value of attribute part_notes.



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# File 'lib/musicality/composition/sequencing/drum_machine/drum_pattern.rb', line 4

def part_notes
  @part_notes
end

Class Method Details

.apply_accents(notes, accent_offsets) ⇒ Object 



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# File 'lib/musicality/composition/sequencing/drum_machine/drum_pattern.rb', line 54

def self.apply_accents notes, accent_offsets
  cum_dur = 0

  notes.each do |note|
    if note.pitches.any? && accent_offsets.include?(cum_dur)
      note.mark_accented!
    end
    cum_dur += note.duration
  end
end

.determine_accent_offsets(accent_rhythm) ⇒ Object 



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# File 'lib/musicality/composition/sequencing/drum_machine/drum_pattern.rb', line 40

def self.determine_accent_offsets accent_rhythm
  accent_offsets = []
  cum_dur = 0

  accent_rhythm.durations.each do |dur|
    if dur > 0
      accent_offsets.push cum_dur
    end
    cum_dur += dur
  end

  return accent_offsets
end