Class: Sound::Data

Inherits:
Object
  • Object
show all
Defined in:
lib/sound/data.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(format = Format.new) ⇒ Data

Returns a new instance of Data.



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# File 'lib/sound/data.rb', line 6

def initialize(format = Format.new)
  @format = format
  @pcm_data = []
end

Instance Attribute Details

#duration ⇒ Object (readonly)

Returns the value of attribute duration.



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# File 'lib/sound/data.rb', line 5

def duration
  @duration
end

#format ⇒ Object (readonly)

Returns the value of attribute format.



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# File 'lib/sound/data.rb', line 5

def format
  @format
end

#pcm_data ⇒ Object (readonly)

Returns the value of attribute pcm_data.



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# File 'lib/sound/data.rb', line 5

def pcm_data
  @pcm_data
end

Instance Method Details

#generate_sine_wave(freq, duration, volume) ⇒ Object Also known as: sine_wave 



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# File 'lib/sound/data.rb', line 10

def generate_sine_wave(freq, duration, volume)
  @pcm_data = []
  @duration = duration
  ramp = 200.0
  samples = (@format.sample_rate/2*duration/1000.0).floor

  samples.times do |sample|

    angle = (2.0*Math::PI*freq) * sample/samples * duration/1000
    factor = Math.sin(angle)
    x = 32768.0*factor*volume

    if sample < ramp
      x *= sample/ramp
    end
    if samples - sample < ramp
      x *= (samples - sample)/ramp
    end

    @pcm_data << x.floor
  end

  self
end