iOS screen rotation broken in 0.15

[extrawurst]

Bevy version

bevy 0.15

[Optional] Relevant system information

MacOs 15.1.1 (24B91)
XCode 16.1 (16B40)

Tested in Simulator

AdapterInfo { name: "Apple iOS simulator GPU", vendor: 0, device: 0, device_type: DiscreteGpu, driver: "", driver_info: "", backend: Metal }

What you did

Just running bevy_mobile_example in the iOS Simulator

What went wrong

If you rotate the device, bevy should adapt its viewport from portrait to landscape but it is stuck in portrait:

[seivan]

@extrawurst Have you tested raw WGPU + Winit?
What Winit / Window settings did you have?

[extrawurst]

@extrawurst Have you tested raw WGPU + Winit?

No

What Winit / Window settings did you have?

The one the bevy_mobile_example inside the bevy repo uses

[Braymatter]

Adding on to this - Winit/bevy_winit is emitting window resized events, with appropriate dimensions:

What is interesting is that touch events don't register when tapping the black / unrendered portion of the screen:

On my app animations are still running so I think we're still requesting redraws from winit - since there wasn't a new version of Winit from version 0.14 to 0.15, I think the issue is definitely in the bevy code.

I'm unsure what actually determines the render area for the camera etc. but as Winit is not sending touch gestures back up to bevy in the black area - it seems as though the actual winit-window isn't actually resizing (unless we're doing bounds checking on touch/pointer inputs somewhere I didn't see)

[HackerFoo]

I spent some time on this. The render target has the right dimensions after changing window size, and Bevy can only request a window size change, but the iOS backend ignores this anyway.

Furthermore, the sizes in winits WinitView::draw_rect and WinitView::layout_subviews all seem correct, and the file hasn't been touched for about 2 years. I think it's also unlikely that Apple changed the API.

Nonetheless, this can be tested easily by running an iOS app as "Design for iPad" and resizing the window. No matter how the window is resized, the rendered rectangle stays the same size, surrounded by gray.

[HackerFoo]

I ran git bisect using the mobile example and it led to this commit upgrading to wgpu 23.

[HackerFoo]

Downgrading wgpu fixed my app. So now I need to bisect wgpu.

[HackerFoo]

Starting with wgpu-v23.0.1, reverting gfx-rs/wgpu#6535 then gfx-rs/wgpu#6535 then gfx-rs/wgpu#6107 fixed the problem: https://github.com/HackerFoo/wgpu/commits/fix/

[BenjaminBrienen]

Can you create an issue in wgpu to address this regression?