Class: Win32::Sound

Inherits:
Object
  • Object
show all
Defined in:
lib/win32/wave_out_play_freq.rb

Class Method Summary collapse

Class Method Details

.play_freq(frequency = 440, duration = 1000, volume = 1, pause_execution = false) ⇒ Object

Plays a frequency for a specified duration at a given volume. Defaults are 440Hz, 1 second, full volume. Result is a single channel, 44100Hz sampled, 16 bit sine wave. If multiple instances are plays in simultaneous threads, they will be started and played at the same time

ex.: threads = []

[440, 660].each do |freq|
  threads << Thread.new { Win32::Sound.play_freq(freq) }
end
threads.each { |th| th.join }

the first frequency in this array (440) will wait until the thread for 660 finished calculating its PCM array and they will both start streaming at the same time.



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# File 'lib/win32/wave_out_play_freq.rb', line 24

def self.play_freq(frequency = 440, duration = 1000, volume = 1, pause_execution = false)

  if frequency > HIGH_FREQUENCY || frequency < LOW_FREQUENCY
    raise ArgumentError, 'invalid frequency'
  end
  
  if duration < 0 || duration > 5000
    raise ArgumentError, 'invalid duration'
  end

  stream(pause_execution) { |wfx|
    data = generate_pcm_integer_array_for_freq(frequency, duration, volume)
    data_buffer = FFI::MemoryPointer.new(:int, data.size)
    data_buffer.write_array_of_int data
    buffer_length = wfx[:nAvgBytesPerSec]*duration/1000
    WAVEHDR.new(data_buffer, buffer_length)
  }
  
end