updating to ES6 in zh-Hans

Author: two-ticks

src/data/examples/zh-Hans/08_Math/20_Graphing2DEquations.js

@@ -1,7 +1,7 @@
-/*
+/**
  * @name Graphing 2D Equations
  * @frame 710, 400
- * @description Graphics the following equation: sin(n*cos(r) + 5*theta) where n is a function of horizontal mouse location. Original by Daniel Shiffman 
+ * @description Graphics the following equation: sin(n*cos(r) + 5*theta) where n is a function of horizontal mouse location. Original by Daniel Shiffman
  */
 function setup() {
   createCanvas(710, 400);
@@ -10,17 +10,17 @@ function setup() {
 
 function draw() {
   loadPixels();
-  var n = (mouseX * 10.0) / width;
-  var w = 16.0; // 2D space width
-  var h = 16.0; // 2D space height
-  var dx = w / width; // Increment x this amount per pixel
-  var dy = h / height; // Increment y this amount per pixel
-  var x = -w / 2; // Start x at -1 * width / 2
-  var y;
+  let n = (mouseX * 10.0) / width;
+  const w = 16.0; // 2D space width
+  const h = 16.0; // 2D space height
+  const dx = w / width; // Increment x this amount per pixel
+  const dy = h / height; // Increment y this amount per pixel
+  let x = -w / 2; // Start x at -1 * width / 2
+  let y;
 
-  var r;
-  var theta;
-  var val;
+  let r;
+  let theta;
+  let val;
 
   let bw; //variable to store grayscale
   let i;
@@ -30,25 +30,23 @@ function draw() {
 
   for (i = 0; i < cols; i += 1) {
     y = -h / 2;
-
     for (j = 0; j < rows; j += 1) {
-      r = sqrt((x * x) + (y * y)); // Convert cartesian to polar
+      r = sqrt(x * x + y * y); // Convert cartesian to polar
       theta = atan2(y, x); // Convert cartesian to polar
       // Compute 2D polar coordinate function
       val = sin(n * cos(r) + 5 * theta); // Results in a value between -1 and 1
       //var val = cos(r);                            // Another simple function
       //var val = sin(theta);                        // Another simple function
       bw = color(((val + 1) * 255) / 2);
       index = 4 * (i + j * width);
-      pixels[index]       = red(bw);
+      pixels[index] = red(bw);
       pixels[index + 1] = green(bw);
       pixels[index + 2] = blue(bw);
       pixels[index + 3] = alpha(bw);
 
       y += dy;
     }
-
     x += dx;
   }
   updatePixels();
-}
+}