noise-buffer - npm Package Compare versions

Comparing version 1.0.1 to 2.0.0

index.js

 // courtesy of http://noisehack.com/generate-noise-web-audio-api/
-module.exports = function(length) {
+module.exports = function(length, type) {
+  type = type || 'white';
+
   var sampleRate = 44100;
@@ -7,8 +9,41 @@ var samples = length * sampleRate;
   var noiseBuffer = context.createBuffer(1, samples, sampleRate);
+  var output = noiseBuffer.getChannelData(0);
 
-  var output = noiseBuffer.getChannelData(0);
-  for (var i = 0; i < samples; i++) {
-    output[i] = Math.random() * 2 - 1;
+  switch(type) {
+    case 'white':
+      // http://noisehack.com/generate-noise-web-audio-api/
+      for (var i = 0; i < samples; i++) {
+        output[i] = Math.random() * 2 - 1;
+      }
+      break;
+    case 'pink':
+      // just completely http://noisehack.com/generate-noise-web-audio-api/
+      var b0, b1, b2, b3, b4, b5, b6;
+      b0 = b1 = b2 = b3 = b4 = b5 = b6 = 0.0;
+      for (var i = 0; i < samples; i++) {
+        var white = Math.random() * 2 - 1;
+        b0 = 0.99886 * b0 + white * 0.0555179;
+        b1 = 0.99332 * b1 + white * 0.0750759;
+        b2 = 0.96900 * b2 + white * 0.1538520;
+        b3 = 0.86650 * b3 + white * 0.3104856;
+        b4 = 0.55000 * b4 + white * 0.5329522;
+        b5 = -0.7616 * b5 - white * 0.0168980;
+        output[i] = b0 + b1 + b2 + b3 + b4 + b5 + b6 + white * 0.5362;
+        output[i] *= 0.11; // (roughly) compensate for gain
+        b6 = white * 0.115926;
+      }
+      break;
+    case 'brown':
+      // just completely http://noisehack.com/generate-noise-web-audio-api/
+      var lastOut = 0.0;
+      for (var i = 0; i < samples; i++) {
+        var white = Math.random() * 2 - 1;
+        output[i] = (lastOut + (0.02 * white)) / 1.02;
+        lastOut = output[i];
+        output[i] *= 3.5; // (roughly) compensate for gain
+      }
+      break;
   }
+
   return noiseBuffer;
 };

package.json

 {
   "name": "noise-buffer",
-  "version": "1.0.1",
+  "version": "2.0.0",
   "description": "Generate `AudioBuffer`s of white noise.",
@@ -5,0 +5,0 @@ "repository": "github:itsjoesullivan/noise-buffer",

readme.md

 ## NoiseBuffer
 
-Generate `AudioBuffer`s of white noise.
+Generate `AudioBuffer`s of noise.
 
+Code taken from [NoiseHack.com](http://noisehack.com/generate-noise-web-audio-api/)
+
 ## Usage
@@ -12,4 +14,7 @@
 
-var noise = NoiseBuffer(1); // One second of noise
+var noise = NoiseBuffer(1); // One second of white noise
+var noise = NoiseBuffer(1, 'pink'); // One second of pink noise
+var noise = NoiseBuffer(1, 'brown'); // One second of brown noise
 
 noise instanceof AudioBuffer // true
+```

No alert changes

Improved metrics

Total package byte prevSize

2407

increased by157.43%

Lines of code

45

increased by275%

Number of lines in readme file

20

increased by33.33%

No dependency changes