Using WebGL in UIWebView logs warning in Xcode Console

Originator:mkalmes
Number:rdar://44602283 Date Originated:19-Sep-2018 04:45 PM
Status:Open Resolved:
Product:iOS + SDK Product Version:iOS 12.0
Classification:Other Bug Reproducible:Always
 
Summary:
When using WebGL in a `UIWebView`, the following warning will be logged to the Xcode console:

```
2018-09-19 16:02:43.073254+0200 WebGLDemo[1791:105094] CoreAnimation: [EAGLContext renderbufferStorage:fromDrawable:] was called from a non-main thread in an implicit transaction! Note that this may be unsafe without an explicit CATransaction or a call to [CATransaction flush].
```

This warning will not be logged when using `WKWebView`.

This behavior may result in a crash, when the application will be send to the background. Please refer to the attached crash logs.

Steps to Reproduce:
1. Open the attached demo project
2. Tap on “WebGL with UIWebView”

Expected Results:
No warning will be logged.

Actual Results:
The following warning will be logged:

```
2018-09-19 16:02:43.073254+0200 WebGLDemo[1791:105094] CoreAnimation: [EAGLContext renderbufferStorage:fromDrawable:] was called from a non-main thread in an implicit transaction! Note that this may be unsafe without an explicit CATransaction or a call to [CATransaction flush].
```

Version:
iOS 12.0

Notes:
Notice that `UIWebView` is deprecated since iOS 12.0, but Google-Mobile-Ads-SDK [supports iOS 6 with v7.33.1][1] and still uses `UIWebView`.

[1]: https://github.com/CocoaPods/Specs/blob/master/Specs/5/9/a/Google-Mobile-Ads-SDK/7.33.1/Google-Mobile-Ads-SDK.podspec.json

Comments

The demo project can be found at https://github.com/chefkoch-dev/bugreport.apple.com/tree/master/44602283%20-%20Using%20WebGL%20in%20UIWebView%20logs%20warning%20in%20Xcode%20Console

By mkalmes at Sept. 20, 2018, 5:58 a.m. (reply...)

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