nim-webaudio

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Nim Wrapper for the Web Audio API

Example code for creating an oscillator that responds to clicks on the screen and fades and changes pitch over time.

Try it!

import webaudio
import dom

var ctx = newAudioContext()

var gain = ctx.createGain()
gain.gain.value = 0.5
gain.connect(ctx.destination)

var osc = ctx.createOscillator()
osc.type = "square"
osc.frequency.value = 440.0
osc.connect(gain)
osc.start()

discard window.setInterval(
  proc() =
    if gain.gain.value > 0.0:
      gain.gain.value -= 0.01
      if gain.gain.value < 0.0:
        gain.gain.value = 0.0
  , 30)

discard window.setInterval(
  proc() =
    osc.frequency.value *= 0.5
    if osc.frequency.value < 20.0:
      gain.gain.value = 0.0
  , 60)

window.addEventListener("mousedown") do(e: Event):
  osc.stop()
  osc = ctx.createOscillator()
  osc.type = "square"
  osc.frequency.value = 880.0
  osc.connect(gain)
  gain.gain.value = 0.5
  osc.start()