229706 2021-08-31 03:24:43 -0700 REGRESSION (Safari 14): webgl_loader_texture_basis three.js example sometimes fails 2021-10-27 00:46:32 -0700 1 1 1 Unclassified WebKit WebKit2 Safari 14 iPhone / iPad iOS 14 NEW InRadar P2 Normal --- 1 michael.herzog webkit-unassigned achristensen ap blascoburguillos cdumez dino kkinnunen sabouhallawa simon.fraser webkit-bug-importer oldest_to_newest 1788851 0 michael.herzog 2021-08-31 03:24:43 -0700 The following example pages decodes a texture in a web worker, transfers the result into the main thread via "postMessage()" and then renders the result on a plane. https://threejs.org/examples/webgl_loader_texture_basis Expected behavior: The texture is always rendered correctly. Actual behavior: Sometimes the plane is white since no texture is applied. This only happens sporadicly (maybe one out of ten reloads). A user at GitHub found out that the root cause of this issue is a missing message from the worker. Meaning the worker sends the message but it never reaches the main thread. https://github.com/mrdoob/three.js/issues/19717#issuecomment-653581829 This issue only happens in WebKit based browsers on iOS, iPadOS and macOS. According to the comments at GitHub the example used to work consistently in earlier version of Safari (meaning < 14). 1790328 1 cdumez 2021-09-03 13:19:47 -0700 Thank you for the bug report and the test site. It looks like I can I am able to reproduce on Safari 15 on macOS. 1790338 2 cdumez 2021-09-03 13:39:37 -0700 Hmm, I see the page sending 2 messages to the worker and us dispatching those 2 message events on the WorkerGlobalScope. However, I do not see any messages being sent *from* the worker (no WorkerGlobalScope.postMessage() or MessagePort.postMessage() calls). 1790369 3 cdumez 2021-09-03 14:39:52 -0700 I don't think this is an issue with postMessage(). The worker simply doesn't call postMessage() to send back the results, even though it received 2 messages from the main thread. So presumably, whatever operation is happening between the worker receiving the messages and the worker calling postMessage() with the results is getting stuck, sometimes. 1790393 4 cdumez 2021-09-03 15:02:11 -0700 Since canvas is involved, I tried disabling the GPU process but it didn't help. 1790528 5 michael.herzog 2021-09-05 01:08:35 -0700 The worker definitely calls "postMessage()" at this place: https://github.com/mrdoob/three.js/blob/105bd07ffce14f8f8982417e16b99c0d066ce3f1/examples/jsm/loaders/BasisTextureLoader.js#L418 Interestingly, when I add a console.log() right before this line, you see a console log when the demo works. However, when the plane keeps white (so when the issue appears), there is no log in the console. 1790580 6 ap 2021-09-05 14:59:12 -0700 Re-titling to say what we know about the issue, as it's been demonstrated to NOT be related to postMessage(), given that the execution doesn't even reach postMessage() in the worker. 1790926 7 webkit-bug-importer 2021-09-07 03:25:17 -0700 <rdar://problem/82814418> 1809194 8 blascoburguillos 2021-10-27 00:46:32 -0700 I´m also experiencing this issue. Any news or updates?