vail/static/vail.js

// jshint asi:true

var short = 80
var long = 200
var audioFreq = 660
var audioFreqMe = audioFreq * 6 / 5 // I think this works out to a minor third

var ac = new AudioContext()

var mygain = ac.createGain()
mygain.connect(ac.destination)
mygain.gain.value = 0

var myosc = ac.createOscillator()
myosc.connect(mygain)
myosc.frequency.value = audioFreqMe
myosc.start()

var theirgain = ac.createGain()
theirgain.connect(ac.destination)
theirgain.gain.value = 0

var theirosc = ac.createOscillator()
theirosc.connect(theirgain)
theirosc.frequency.value = audioFreq
theirosc.start()

var repeatInterval


function message(event) {
  let now = ac.currentTime
  let duration = Number(event.data) || 0
  duration = Math.min(duration, long)
  
  if (now === 0) {
    // Audio Context hasn't started, we can't make sound yet
    return
  }
  
  theirgain.gain.linearRampToValueAtTime(0.1, now + 0.01)
  mygain.gain.setValueAtTime(0.1, now + duration/1000)
  theirgain.gain.linearRampToValueAtTime(0.0, now + 0.01 + duration/1000)
}

function send(duration) {
  let now = ac.currentTime
  window.socket.send(duration)
  
  if (now === 0) {
    return
  }

  mygain.gain.linearRampToValueAtTime(0.1, now + 0.01)
  mygain.gain.setValueAtTime(0.1, now + duration/1000)
  mygain.gain.linearRampToValueAtTime(0.0, now + 0.01 + duration/1000)
}

function key(event) {
  let duration = 0
  
  ac.resume()

  if (event.repeat) {
    // Ignore key repeats generated by the OS, we do this ourselves
    return
  }

  if ((event.button === 0) || (event.code == "Period") || (event.key == "Shift")) {
    duration = short
  }
  if ((event.button === 2) || (event.code == "Slash") || (event.code == "KeyZ")) {
    duration = long
  }
  if (duration === 0) {
    return
  }
  
  if (repeatInterval) {
    clearInterval(repeatInterval)
  }

  if (event.type.endsWith("down")) {
    send(duration)
    repeatInterval = setInterval(() => {send(duration)}, duration + short)
  }
}

function canWeJustNot(event) {
  event.preventDefault()
  return false
}

function init() {
  let wsUrl = new URL(window.location)
  wsUrl.protocol = "ws:"
  wsUrl.pathname += "chat"
  window.socket = new WebSocket(wsUrl)
  window.socket.addEventListener("message", message)

  // disable RMB context menu
  document.addEventListener("contextmenu", e => canWeJustNot(e))
  document.addEventListener("mousedown", e => key(e))
  document.addEventListener("mouseup", e => key(e))
  document.addEventListener("keydown", e => key(e))
  document.addEventListener("keyup", e => key(e))
}


if (document.readyState === "loading") {
  document.addEventListener("DOMContentLoaded", init)
} else {
  init()
}