Bug 227081 – Using a video as a source for a WebGL texture is slow and hangs on iOS 15

• Status: RESOLVED
• Resolution: FIXED
• Component: WebGL

[Paris Morgan]

Created attachment 431562 [details]
Video of the repro app running on an iPhone12 Pro Max with iOS 15

On iOS 15 using a video as a texture is very slow and hangs. This is a regression from iOS 14.6. 

Repro app: https://8w.8thwall.app/performance-test-video-texture
Repro code: https://codesandbox.io/s/video-texture-performance-test-hmybu

This sample code uses a Three.js THREE.VideoTexture as the texture for a material on a cube. Result:
- iPhone 12 Pro Max iOS 15.0: The render loop takes ~60 ms and has constant hangs with both WebGL 1 and WebGL 2, and with "WebGL via Metal" = true / false. 
- iPhone 12 Pro iOS 14.6: The render loops takes 4.2 ms with no hangs with both WebGL 1 and WebGL 2.
As noted above I have tested with WebGL 1 / 2 and "WebGL via Metal" = true / false (on iOS 15), and no combination fixes the issue on iOS 15 or causes it to repro on iOS 14.6.

Attached is a video of the repro app. Please let me know if I can provide more info, thank you.

[Paris Morgan]

Created attachment 431563 [details]
Video of the repro app running on an Phone 12 Pro with iOS 14.6

[Kenneth Russell]

Kimmo, would you be able to triage this since it's happening on hardware? May be related to Bug 226830, though that one seems specific to video elements created from getUserMedia.

[Kenneth Russell]

Note that this is a key code path that was carefully ensured to retain performance in the ANGLE/GLES code path. Not sure whether the GPU process has been deployed in Safari on iOS 15, or whether this might be a regression in ANGLE/Metal.

[Kenneth Russell]

Actually, this may be a duplicate of Bug 223740.

[Kimmo Kinnunen]

Created attachment 432031 [details]
Patch

[Radar WebKit Bug Importer]

<rdar://problem/79673064>

[Eric Carlson]

Comment on attachment 432031 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=432031&action=review

This looks great to me, thanks!

> Source/WebKit/Scripts/webkit/tests/TestWithCVPixelBufferMessageReceiver.cpp:2
> + * Copyright (C) 2010-2021 Apple Inc. All rights reserved.

Probably only need `2021` for a new file.

> Source/WebKit/Scripts/webkit/tests/TestWithCVPixelBufferMessages.h:2
> + * Copyright (C) 2010-2021 Apple Inc. All rights reserved.

Ditto

> Source/WebKit/Scripts/webkit/tests/TestWithCVPixelBufferMessagesReplies.h:2
> + * Copyright (C) 2010-2021 Apple Inc. All rights reserved.

Ditto

[Kenneth Russell]

Amazing diagnosis and fix Kimmo!

[Kimmo Kinnunen]

Created attachment 432153 [details]
Patch for landing

[EWS]

Committed r279221 (239107@main): <https://commits.webkit.org/239107@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 432153 [details].

[Kimmo Kinnunen]

Thanks for the report and the test case!