audio: add support for web audio API

Author: merongivian

opal/browser/audio.rb

@@ -0,0 +1,48 @@
+require 'browser/audio/node'
+
+module Browser; module Audio
+
+class Context
+  include Native
+
+  alias_native :destination
+  alias_native :listener
+  alias_native :state
+
+  alias_native :sample_rate, :sampleRate
+  alias_native :current_time, :currentTime
+
+  def initialize
+    super `new AudioContext()`
+  end
+
+  def gain
+    Node::Gain.new(self)
+  end
+
+  def oscillator
+    Node::Oscillator.new(self)
+  end
+
+  def delay
+    Node::Delay.new(self)
+  end
+
+  def dynamics_compressor
+    Node::DynamicsCompressor.new(self)
+  end
+
+  def biquad_filter
+    Node::BiquadFilter.new(self)
+  end
+
+  def stereo_panner
+    Node::StereoPanner.new(self)
+  end
+
+  alias_native :suspend
+  alias_native :resume
+  alias_native :close
+end
+
+end; end

opal/browser/audio/node.rb

@@ -0,0 +1,186 @@
+module Browser; module Audio; module Node;
+
+module Pluggable
+  def connect(other_node)
+    `#@native.connect(#{Native.convert(other_node)})`
+  end
+
+  def disconnect(other_node, options = {})
+    other_node = Native.try_convert(other_node)
+    output     = options[:output] || 0
+    input      = options[:input]  || 0
+
+    if options
+      `#@native.disconnect(#{other_node}, #{output}, #{input}) || nil`
+    elsif other_node
+      `#@native.disconnect(#{other_node})`
+    else
+      `#@native.disconnect()`
+    end
+  end
+end
+
+class Gain
+  include Native
+  include Pluggable
+
+  alias_native :value, :gain
+
+  def initialize(audio_context)
+    super `#{audio_context.to_n}.createGain()`
+  end
+end
+
+class Oscillator
+  TYPES = %i(sine square sawtooth triangle custom)
+
+  include Native
+  include Pluggable
+
+  alias_native :start
+  alias_native :stop
+
+  def initialize(audio_context)
+    super `#{audio_context.to_n}.createOscillator()`
+  end
+
+  def type=(type)
+    unless TYPES.include?(type)
+      raise ArgumentError, "type #{type} doesn't exists"
+    end
+
+    `#@native.type =  type`
+  end
+
+  def type
+    `#@native.type`
+  end
+
+  def frequency=(frequency)
+    `#@native.frequency.value = frequency`
+  end
+
+  def frequency
+    `#@native.frequency.value`
+  end
+
+  def detune=(detune)
+    `#@native.detune.value = detune`
+  end
+
+  def detune
+    `#@native.detune.value`
+  end
+end
+
+class Delay
+  include Native
+  include Pluggable
+
+  def initialize(audio_context, max_time)
+    super `#{audio_context.to_n}.createDelay(max_time || 1)`
+  end
+
+  def time=(time)
+    `#@native.time.value = time`
+  end
+
+  def time
+    `#@native.time.value`
+  end
+end
+
+class DynamicsCompressor
+  include Native
+  include Pluggable
+
+  alias_native :reduction
+
+  def treshold=(treshold)
+    `#@native.treshold.value = treshold`
+  end
+
+  def treshold
+    `#@native.treshold.value`
+  end
+
+  def knee=(knee)
+    `#@native.knee.value = knee`
+  end
+
+  def knee
+    `#@native.knee.value`
+  end
+
+  def ratio=(ratio)
+    `#@native.ratio.value = ratio`
+  end
+
+  def ratio
+    `#@native.ratio.value`
+  end
+
+  def attack=(attack)
+    `#@native.attack.value = attack`
+  end
+
+  def attack
+    `#@native.attack.value`
+  end
+
+  def release=(release)
+    `#@native.release.value = release`
+  end
+
+  def release
+    `#@native.release.value`
+  end
+end
+
+class BiquadFilter
+  include Native
+  include Pluggable
+
+  def initialize(audio_context)
+    super `#{audio_context.to_n}.createBiquadFilter()`
+  end
+
+  def detune=(detune)
+    `#@native.detune.value = #{@detune = detune}`
+  end
+
+  def q=(q)
+    `#@native.q.value = q`
+  end
+
+  def q
+    `#@native.q.value`
+  end
+
+  def gain=(gain)
+    `#@native.gain.value = gain`
+  end
+
+  def gain
+    `#@native.gain.value`
+  end
+end
+
+class StereoPanner
+  include Native
+  include Pluggable
+
+  def initialize(audio_context)
+    super `#{audio_context.to_n}.createStereoPanner()`
+  end
+
+  def pan=(pan)
+    `#@native.pan.value = pan`
+  end
+
+  def pan
+    `#@native.pan.value`
+  end
+end
+
+end; end; end