AudioWorklet prototype

third_party/WebKit/LayoutTests/webaudio/audioworklet/processors.js

+'use strict'
+
+registerProcessor('bypass', class Bypass extends AudioWorkletProcessor {
+  constructor () {
+    super();
+  }
+
+  process (input, output) {
+    let inputChannelData = input.getChannelData(0);
+    let outputChannelData = output.getChannelData(0);
+    outputChannelData.set(inputChannelData);
+  }
+});
+
+registerProcessor('noise', class Noise extends AudioWorkletProcessor {
+  static get parameterDescriptors () {
+    return [{
+      name: 'gain',
+      defaultValue: 0.25,
+      minValue: 0,
+      maxValue: 1
+    }];
+  }
+
+  constructor () {
+    super();
+  }
+
+  process (input, output, parameters) {
+    let outputChannelData = output.getChannelData(0);
+    let gain = parameters.gain;
+    for (let i = 0; i < 128; ++i) {
+      outputChannelData[i] = Math.random() * gain[i];
+    }
+  }
+});
+
+registerProcessor('onepole', class OnePole extends AudioWorkletProcessor {
+  constructor () {
+    super();
+    this.updateCoefficients_(5000);
+  }
+
+  updateCoefficients_ (cutoffFrequency) {
+    this.b1 = Math.exp(-2 * Math.PI * cutoffFrequency / 48000);
+    this.a0 = 1.0 - this.b1;
+    this.z1 = 0;
+  }
+
+  process (input, output) {
+    let inputChannelData = input.getChannelData(0);
+    let outputChannelData = output.getChannelData(0);
+    for (let i = 0; i < 128; ++i) {
+      this.z1 = inputChannelData[i] * this.a0 + this.z1 * this.b1;
+      outputChannelData[i] = this.z1;
+    }
+  }
+});