tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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webgl-utils.js (1465B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 "use strict";
      5 
      6 const WEBGL_CONTEXT_NAME = "experimental-webgl";
      7 
      8 function isWebGLForceEnabled() {
      9  return Services.prefs.getBoolPref("webgl.force-enabled");
     10 }
     11 
     12 function isWebGLSupportedByGFX() {
     13  let supported = false;
     14 
     15  try {
     16    const gfxInfo = Cc["@mozilla.org/gfx/info;1"].getService(Ci.nsIGfxInfo);
     17    const angle = gfxInfo.FEATURE_WEBGL_ANGLE;
     18    const opengl = gfxInfo.FEATURE_WEBGL_OPENGL;
     19 
     20    // if either the Angle or OpenGL renderers are available, WebGL should work
     21    supported =
     22      gfxInfo.getFeatureStatus(angle) === gfxInfo.FEATURE_STATUS_OK ||
     23      gfxInfo.getFeatureStatus(opengl) === gfxInfo.FEATURE_STATUS_OK;
     24  } catch (e) {
     25    return false;
     26  }
     27  return supported;
     28 }
     29 
     30 function create3DContext(canvas) {
     31  // try to get a valid context from an existing canvas
     32  let context = null;
     33  try {
     34    context = canvas.getContext(WEBGL_CONTEXT_NAME);
     35  } catch (e) {
     36    return null;
     37  }
     38  return context;
     39 }
     40 
     41 function createCanvas(doc) {
     42  return doc.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
     43 }
     44 
     45 function isWebGLSupported(doc) {
     46  const supported =
     47    !isWebGLForceEnabled() &&
     48    isWebGLSupportedByGFX() &&
     49    create3DContext(createCanvas(doc));
     50 
     51  return supported;
     52 }
     53 exports.isWebGLSupported = isWebGLSupported;