[Webkit-unassigned] [Bug 264684] New: "context lost" when getting WebGL context

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=264684

            Bug ID: 264684
           Summary: "context lost" when getting WebGL context
           Product: WebKit
           Version: Safari 17
          Hardware: iPhone / iPad
                OS: iOS 17
            Status: NEW
          Severity: Blocker
          Priority: P2
         Component: WebGL
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: andrejohn.mas at gmail.com
                CC: dino at apple.com, kbr at google.com, kkinnunen at apple.com

We are no longer able to get the WebGL context on iOS or iPadOS using release 17, with a "context lost" error being logged.

The issues was discovered using Three.JS, but further investigation reveals this impacts all WebGL applications (those I have tested with).

The following code is enough to cause the issue:

```
  function initWebGL () {
        const canvas = document.querySelector('#canvas');
        canvas.width = window.innerWidth;
        canvas.height = window.innerHeight;

        const glOptions = {
          // antialias: false,
          // alpha: false,
          // premultipliedAlpha: false
        };

        const gl = canvas.getContext('webgl2', glOptions)
          || canvas.getContext('webgl', glOptions)
          || canvas.getContext('experimental-webgl', glOptions);
  }

  initWebGL();
```

Note, this does not impact Safari (17.0 (19616.1.27.211.1)) on MacOS X 14.

Tested with: iOS 17.0.3, iPadOS 17.0.3 and MacOSX 14 (Safari).

Note, discussion in the Three.JS forum: https://discourse.threejs.org/t/three-js-broken-on-ios-17-with-context-lost/58025

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