1 files changed, 111 insertions, 0 deletions
diff --git a/client/lib/util.js b/client/lib/util.js
new file mode 100644
index 0000000..fd48768
--- /dev/null
+++ b/client/lib/util.js
@@ -0,0 +1,111 @@
+import Tone from 'tone'
+import StartAudioContext from './startAudioContext'
+
+const isIphone = (navigator.userAgent.match(/iPhone/i)) || (navigator.userAgent.match(/iPod/i))
+const isIpad = (navigator.userAgent.match(/iPad/i))
+const isAndroid = (navigator.userAgent.match(/Android/i))
+const isMobile = isIphone || isIpad || isAndroid
+const isDesktop = ! isMobile
+
+document.body.classList.add(isMobile ? 'mobile' : 'desktop')
+
+const browser = { isIphone, isIpad, isAndroid, isMobile, isDesktop }
+
+function clamp(n,a,b){ return n<a?a:n<b?n:b }
+function choice (a){ return a[ Math.floor(Math.random() * a.length) ] }
+function mod(n,m){ return n-(m * Math.floor(n/m)) }
+function randint(n){ return (Math.random()*n)|0 }
+function randrange(a,b){ return a + Math.random() * (b-a) }
+function randsign(){ return Math.random() >= 0.5 ? -1 : 1 }
+function lerp(n,a,b){ return (b-a)*n+a }
+function angle(x0,y0,x1,y1){ return Math.atan2(y1-y0,x1-x0) }
+function dist(x0,y0,x1,y1){ return Math.sqrt(Math.pow(x1-x0,2)+Math.pow(y1-y0,2)) }
+function xor(a,b){ a=!!a; b=!!b; return (a||b) && !(a&&b) }
+function shuffle(a){
+  for (var i = a.length; i > 0; i--){
+    var r = randint(i)
+    var swap = a[i-1]
+    a[i-1] = a[r]
+    a[r] = swap
+  }
+  return a
+}
+// returns a gaussian random function with the given mean and stdev.
+function gaussian(mean, stdev) {
+  let y2;
+  let use_last = false;
+  return () => {
+    let y1;
+    if (use_last) {
+      y1 = y2;
+      use_last = false;
+    }
+    else {
+      let x1, x2, w;
+      do {
+        x1 = 2.0 * Math.random() - 1.0;
+        x2 = 2.0 * Math.random() - 1.0;
+        w  = x1 * x1 + x2 * x2;               
+      } while( w >= 1.0);
+      w = Math.sqrt((-2.0 * Math.log(w))/w);
+      y1 = x1 * w;
+      y2 = x2 * w;
+      use_last = true;
+    }
+
+    let retval = mean + stdev * y1;
+    if (retval > 0) 
+      return retval;
+    return -retval;
+  }
+}
+
+function requestAudioContext (fn) {
+	if (isMobile) {
+    const container = document.createElement('div')
+    const button = document.createElement('div')
+    button.innerHTML = 'Tap to start - please unmute your phone'
+    Object.assign(container.style, {
+			display: 'block',
+      position: 'absolute',
+      width: '100%',
+      height: '100%',
+      zIndex: '10000',
+      top: '0px',
+      left: '0px',
+      backgroundColor: 'rgba(0, 0, 0, 0.8)',
+    })
+		Object.assign(button.style, {
+			display: 'block',
+		  position: 'absolute',
+		  left: '50%',
+		  top: '50%',
+			padding: '20px',
+		  backgroundColor: '#7F33ED',
+		  color: 'white',
+		  fontFamily: 'monospace',
+		  borderRadius: '3px',
+		  transform: 'translate3D(-50%,-50%,0)',
+		  textAlign: 'center',
+			lineHeight: '1.5',
+			width: '150px',
+    })
+    container.appendChild(button)
+    document.body.appendChild(container)
+    StartAudioContext.setContext(Tone.context)
+    StartAudioContext.on(button)
+    StartAudioContext.onStarted(_ => {
+      container.remove()
+			fn()
+  	})
+	} else {
+		fn()
+	}
+}
+
+export {
+  clamp, choice, mod, lerp, angle, dist, xor,
+  randint, randrange, randsign, shuffle, gaussian,
+  browser, requestAudioContext,
+}
+