Bug 228904 – WebGL 2.0 doesn't work on A8 devices (iPad mini 4, iPad Air 2)

• Component: WebGL
• Status: RESOLVED FIXED

[Dean Jackson]

WebGL 2.0 doesn't work on A8 devices (iPad mini 4, iPad Air 2)

[Dean Jackson]

rdar://79198313

[Dean Jackson]

Created attachment 435150 [details]
Patch

[Dean Jackson]

Created attachment 435151 [details]
Patch

[John Cunningham]

Comment on attachment 435151 [details]
Patch

LGTM

[Dean Jackson]

Committed r280782 (240365@main): <https://commits.webkit.org/240365@main>

Hey Dean or John,

Any update on what version of iOS will include the version of WebKit that has this fix?

Thanks

[Kyle Piddington]

I'm not sure if this fix took, I'm not seeing us switch automatically to the GL backend on older devices. That, or it was lost in a refactor. 
Visiting https://www.soft8soft.com/webglreport/?v=2 with Metal on ANGLE enabled claims that webGL2 is not supported, where disabling Metal on ANGLE shows support.

[Kyle Piddington]

Reopening, on an iPad Air 2, I'm seeing us fail to switch back to the OpenGL backend.

[Kenneth Russell]

+Kimmo

Perhaps refactors for the GPU process changed the semantics in this area?

platformSupportsMetal() is still present in Source/WebCore/platform/graphics/cocoa/GraphicsContextGLCocoa.mm and it's still called during context creation.

[Dean Jackson]

New radar: rdar://88300200

[Kimmo Kinnunen]

Maybe the ANGLE roll pulled in new ANGLE that defaults to Metal unless OPENGLES explicitly asked..

[Kenneth Russell]

Possible - not sure. Note Chromium's starting to ship ANGLE's OpenGL backend on macOS in preparation for shipping the Metal backend, so it's still known to work to some degree.

[Kimmo Kinnunen]

Seems to be that iOS sandbox denies EAGL usage.

[Harsh]

Hi- Does this issue impact only some devices? What all would be those devices? Also would love some insight on the fix for this. Thanks for the support!

[Harsh]

Hi, I see the two bugs that this issue was dependent on are already closed. Is there a fix for this being release in next version?

[Kimmo Kinnunen]

(In reply to Harsh from comment #15)
> Hi, I see the two bugs that this issue was dependent on are already closed.
> Is there a fix for this being release in next version?

This should fix using WebGL2 on iPad mini 4 on iOS 15.4. 
This should be fixed in iOS 15.4 seed 4.

Hey Kimmo,

Just tested this case on iPad Air 2 on iOS 15.4 and was still able to reproduce the issue. Your last comment noted that it should be fixed on mini 4 on 15.4 - does this mean that it should be fixed on Air 2 as well?

[rahsaraf]

Following up on this as we're still seeing the issue on the iPad Air 2. 

Did the fix that went out in iPadOS 15.4 only affect the iPad Mini 4? 

If so, is there an expected fix and timeframe for the iPad Air 2 (A8X in the iPad Air 2 vs A8 in the iPad Mini 4)