Don't read Math all the time

diff --git a/js/animation.js b/js/animation.js
index fc6246ec2d6e914cd6e649909b33aca52816263a..907df5db1c635442bf43002f352a236ac446b56c 100644 (file)
--- a/js/animation.js
+++ b/js/animation.js
@@ -5,14 +5,16 @@
       fps = 30,
       lastFrame = 0,
       speed = 1,
-      size = 5 + rand(10);
+      size = 5 + rand(10),
+      r = Math.random,
+      pi = Math.PI;
 
-  var clear = !!(Math.random() > 0.5);
-  var changeColor = !!(Math.random() > 0.5);
+  var clear = !!(r() > 0.5);
+  var changeColor = !!(r() > 0.5);
   var items = Array(rand(10) + 6).fill(null).map(() => ({
     x: rand(64),
     y: rand(64),
-    angle: Math.random() * 2 * Math.PI,
+    angle: r() * 2 * pi,
     color: Array(3).fill(rand(256))
   }));
   var shapes = [square, circle, heart, chaos, lineChaos];
@@ -21,7 +23,7 @@
   var position = positions[rand(positions.length)];
 
   function rand (x) {
-    return Math.floor(Math.random() * x);
+    return Math.floor(r() * x);
   }
 
   function square(item) {
@@ -34,7 +36,7 @@
 
     var p = position(item);
     context.beginPath();
-    context.arc(p.x, p.y, size / 2, 0, 2 * Math.PI);
+    context.arc(p.x, p.y, size / 2, 0, 2 * pi);
     context.fill();
   }
 
@@ -71,12 +73,12 @@
     context.fillRect(p.x, p.y, size, size);
 
     context.beginPath();
-    context.arc(p.x + size / 2, p.y, size / 2, 0, 2 * Math.PI, false);
+    context.arc(p.x + size / 2, p.y, size / 2, 0, 2 * pi, false);
     context.fill();
     context.closePath();
 
     context.beginPath();
-    context.arc(p.x + size, p.y + size / 2, size / 2, 0, 2 * Math.PI, false);
+    context.arc(p.x + size, p.y + size / 2, size / 2, 0, 2 * pi, false);
     context.fill();
     context.closePath();
   }