devtools/client/webaudioeditor/test/doc_buffer-and-array.html


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56

<!-- Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/ -->
<!doctype html>

<html>
  <head>
    <meta charset="utf-8"/>
    <title>Web Audio Editor test page</title>
  </head>

  <body>

    <script type="text/javascript;version=1.8">
      "use strict";

      let audioURL = "http://example.com/browser/devtools/client/webaudioeditor/test/440hz_sine.ogg";

      let ctx = new AudioContext();
      let bufferNode = ctx.createBufferSource();
      let shaperNode = ctx.createWaveShaper();
      shaperNode.curve = generateWaveShapingCurve();

      let xhr = getBuffer(audioURL, () => {
        ctx.decodeAudioData(xhr.response, (buffer) => {
          bufferNode.buffer = buffer;
          bufferNode.connect(shaperNode);
          shaperNode.connect(ctx.destination);
        });
      });

      function generateWaveShapingCurve() {
        let frames = 65536;
        let curve = new Float32Array(frames);
        let n = frames;
        let n2 = n / 2;

        for (let i = 0; i < n; ++i) {
          let x = (i - n2) / n2;
          let y = Math.atan(5 * x) / (0.5 * Math.PI);
        }

        return curve;
      }

      function getBuffer (url, callback) {
        let xhr = new XMLHttpRequest();
        xhr.open("GET", url, true);
        xhr.responseType = "arraybuffer";
        xhr.onload = callback;
        xhr.send();
        return xhr;
      }
    </script>
  </body>

</html>