https://welterbe-siedlungen-berlin.de/wp-content/themes/sdbm-wp-theme/assets/js/detectWebGL.js

1/**
2 * Detects if WebGL is enabled.
3 * Inspired from http://www.browserleaks.com/webgl#howto-detect-webgl
4 *
5 * @return { number } -1 for not Supported,
6 *                    0 for disabled
7 *                    1 for enabled
8 */
9function detectWebGL()
10{
11    // Check for the WebGL rendering context
12    if ( !! window.WebGLRenderingContext) {
13        var canvas = document.createElement("canvas"),
14            names = ["webgl", "experimental-webgl", "moz-webgl", "webkit-3d"],
15            context = false;
16
17        for (var i in names) {
18            try {
19                context = canvas.getContext(names[i]);
20                if (context && typeof context.getParameter === "function") {
21                    // WebGL is enabled.
22                    return 1;
23                }
24            } catch (e) {}
25        }
26
27        // WebGL is supported, but disabled.
28        return 0;
29    }
30
31    // WebGL not supported.
32    return -1;
33}
34
35function isSet(foo) {
36    if(typeof(foo) !== 'undefined') {
37        return true;
38    } else {
39        return false;
40    }
41}