Class: Pachelbel::AudioContext

Inherits:
Object
  • Object
show all
Defined in:
lib/project/Pachelbel.rb

Constant Summary collapse

HTML = 
'<script>' + 'window.AudioContext = window.AudioContext || window.webkitAudioContext;' +
'var audio_context = new AudioContext();' + 'var audio_nodes = [audio_context.destination];' + '</script>'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ AudioContext

Returns a new instance of AudioContext.



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# File 'lib/project/Pachelbel.rb', line 17

def initialize
  @locked = true
  @on_ready = []
  @webview = UIWebView.new
  @webview.delegate = self
  @webview.loadHTMLString HTML, baseURL: nil
end

Instance Attribute Details

#locked ⇒ Object (readonly)

Returns the value of attribute locked.



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# File 'lib/project/Pachelbel.rb', line 4

def locked
  @locked
end

#webview ⇒ Object (readonly)

Returns the value of attribute webview.



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# File 'lib/project/Pachelbel.rb', line 3

def webview
  @webview
end

Instance Method Details

#createGain ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 78

def createGain
  object = GainNode.allocate
  object._audio_context = self
  js_method = UIDevice.currentDevice.systemVersion[0] == '6' ? 'createGainNode' : 'createGain'
  object._index = run_js("audio_nodes.push( audio_context.#{js_method}() );").to_i - 1
  object
end

#createOscillator ⇒ Object

API Constructors



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# File 'lib/project/Pachelbel.rb', line 71

def createOscillator
  object = OscillatorNode.allocate
  object._audio_context = self
  object._index = run_js('audio_nodes.push( audio_context.createOscillator() );').to_i - 1
  object
end

#currentTime ⇒ Object

API Attributes



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# File 'lib/project/Pachelbel.rb', line 48

def currentTime
  run_js('audio_context.currentTime;').to_f
end

#destination ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 52

def destination
  @destination ||= begin
    object = AudioDestinationNode.allocate
    object._audio_context = self
    object._index = 0
    object
  end
end

#listener ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 61

def listener
  run_js('audio_context.listener;')
end

#on_ready(&block) ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 9

def on_ready(&block)
  @locked ? @on_ready.push(block) : yield
end

#run_js(script) ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 13

def run_js(script)
  @webview.stringByEvaluatingJavaScriptFromString script
end

#sampleRate ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 65

def sampleRate
  run_js('audio_context.sampleRate;').to_f
end

#webView(_, shouldStartLoadWithRequest: request, navigationType: _) ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 34

def webView(_, shouldStartLoadWithRequest: request, navigationType: _)
  case request.URL.absoluteString
  when "let://freedom.ring"
    @locked = false
    @on_ready.each(&:call)
    @on_ready = nil
    return false
  else
    return true
  end
end

#webViewDidFinishLoad(_) ⇒ Object 



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# File 'lib/project/Pachelbel.rb', line 25

def webViewDidFinishLoad(_)
  run_js 'var unlock_iframe = document.createElement("IFRAME");
          unlock_iframe.setAttribute("src", "let://freedom.ring");'

  run_js 'var pollster = function() { if (audio_context.currentTime === 0) { setTimeout(pollster, 0); } else { document.documentElement.appendChild(unlock_iframe); } }'

  run_js 'audio_context.createOscillator().noteOn(0); setTimeout(pollster, 0);'
end