Bug 229989

Summary: WebGL scissor drawing results have changed in iOS 15 beta
Product: WebKit Reporter: Takuya Yamazaki <zproject.develop>
Component: WebGLAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: dino, gman, kbr, kkinnunen, kpiddington, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Safari Technology Preview   
Hardware: iPhone / iPad   
OS: Other   
See Also: https://bugs.webkit.org/show_bug.cgi?id=230618
Attachments:
Description Flags
test case to observe gl.scissor(0,0,0,0); appers to work none

Takuya Yamazaki
Reported 2021-09-07 02:53:27 PDT
In WebGLRenderingContext.scissor(), the drawing result when width or height are set to 0 has changed from iOS15. Until iOS14: Nothing is drawn From iOS15: All drawn
Attachments
test case to observe gl.scissor(0,0,0,0); appers to work (385 bytes, text/html)
2021-09-09 06:37 PDT, Kimmo Kinnunen 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Kenneth Russell
Comment 1 2021-09-07 16:24:08 PDT
Sounds like a potential regression in
Kenneth Russell
Comment 2 2021-09-07 16:24:42 PDT
(oops, didn't mean to press "enter") Sounds like a potential regression in ANGLE's Metal backend. Is this tested in the conformance suite?
Kimmo Kinnunen
Comment 3 2021-09-09 06:37:17 PDT
Created attachment 437740 [details] test case to observe gl.scissor(0,0,0,0); appers to work
Kimmo Kinnunen
Comment 4 2021-09-09 06:38:10 PDT
Cannot reproduce the problem with brief tests. Takuya Yamazaki, would you be able to upload a reproduction test case for the problem?
Radar WebKit Bug Importer
Comment 5 2021-09-14 02:54:23 PDT
<rdar://problem/83095006>
Kimmo Kinnunen
Comment 6 2021-10-01 06:50:33 PDT
To the original reporter: If you are using preserveDrawingBuffer: true, then you might try if setting that to false affects the result. If so, then this would be related to bug 230618
Takuya Yamazaki
Comment 7 2022-04-14 02:03:09 PDT
Sorry for the delay in confirming this. This issue was fixed in at least iOS 15.4. It was not fixed in iOS 15.2. We are not aware of iOS 15.3.
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