How to create multiple windows in multiple monitors?

[lewiszlw]

Bevy version

main branch (lastest commit is cd447fb4e68716fb908158ab9ca64d13746a6b97).

[Optional] Relevant system information

AdapterInfo { name: "Apple M1", vendor: 0, device: 0, device_type: IntegratedGpu, driver: "", driver_info: "", backend: Metal }

SystemInfo { os: "MacOS 13.0 ", kernel: "22.1.0", cpu: "Apple M1", core_count: "8", memory: "16.0 GiB" }

[DisplayInfo { id: 1, x: 0, y: 0, width: 1440, height: 900, rotation: 0.0, scale_factor: 2.0, is_primary: true }, DisplayInfo { id: 2, x: -264, y: -1080, width: 1920, height: 1080, rotation: 0.0, scale_factor: 1.0, is_primary: false }]

What you did

I'm trying to run offical example multiple_windows and want second window putted on second monitor. I tried

    let second_window = commands
        .spawn(Window {
            title: "Second window".to_owned(),
            position: WindowPosition::At(IVec2::new(-264, -1080)),
            resolution: WindowResolution::new(1920., 1080.),
            ..default()
        })
        .id();

and

    let second_window = commands
        .spawn(Window {
            title: "Second window".to_owned(),
            position: WindowPosition::Centered(MonitorSelection::Index(1)),   // I tried 0,1,2,3 here
            resolution: WindowResolution::new(1920., 1080.),
            ..default()
        })
        .id();

What went wrong

The second window is always on my primary monitor.

[lewiszlw]

Hi, @Aceeri , could you give a look at this? I can put second window on second monitor when using bevy 0.9.1. I'm not sure if windows as entities pr breaks this or something I missed.

[Aceeri]

I'll double check that this works, never really tested it specifically myself just took existing code.

[Aceeri]

Hmm, it seems to work fine on Windows. I do have a M1 laptop to try and test this on, but I'll try doing that tomorrow.

[Aceeri]

@lewiszlw Would you mind posting the logs from running the code with

position: WindowPosition::Centered(MonitorSelection::Index(1)),

?

Just wondering if there is maybe a WARN about it not finding the second monitor.

[lewiszlw]

2023-02-16T08:38:20.479995Z  INFO bevy_render::renderer: AdapterInfo { name: "Apple M1", vendor: 0, device: 0, device_type: IntegratedGpu, driver: "", driver_info: "", backend: Metal }
2023-02-16T08:38:20.905247Z  INFO bevy_winit::system: Creating new window "Bevy App" (0v0)
2023-02-16T08:38:21.086569Z  INFO bevy_diagnostic::system_information_diagnostics_plugin::internal: SystemInfo { os: "MacOS 13.0 ", kernel: "22.1.0", cpu: "Apple M1", core_count: "8", memory: "16.0 GiB" }
2023-02-16T08:38:21.212242Z  INFO bevy_winit::system: Creating new window "Second window" (4v0)
2023-02-16T08:38:27.260902Z  INFO bevy_winit::system: Closing window 0v0
2023-02-16T08:38:27.316784Z  WARN bevy_winit: Window 0v0 is missing `Window` component, skipping event Destroyed
2023-02-16T08:38:28.674905Z  INFO bevy_window::system: No windows are open, exiting
2023-02-16T08:38:28.677308Z  INFO bevy_winit::system: Closing window 4v0

[SpecificProtagonist]

Works for me on Linux (X11) too.

[Aceeri]

@lewiszlw Would you be open to debugging this further on your end? Can ask me any questions about the windowing code in general.

Could also do it live somewhere if you think that'd be helpful.

[lewiszlw]

Sure, I'll try a deep dive.

[lewiszlw]

I have some findings @Aceeri

1. When I put primary window on primary monitor, if I set a negative number (ex. -200) to Y of position of the second window, the second window will be created on bottom of my primary monitor rather than second monitor (seems the second monitor wasn't detected).
2. When I put primary window on second monitor, if I set a negative number to Y of position of the second window, the second window will be created on second monitor as expected.

Seems the process behind creating primary window on second monitor will init somthing for the second monitor.

This is my monitors arrangement.

[Aceeri]

Hmm, this makes me think we either are or aren't flipping the coordinate space for position in the y direction.

Either way our vertical coordinate space is differing from winits I think.

[lewiszlw]

I tried winit multiwindow example, everything works fine.

[lewiszlw]

There are some talk in #6526, maybe helpful.

[Aceeri]

Can't seem to repro this still, tried moving my monitors around to be in a similar set up but it seems to work fine hmm

[honungsburk]

I've run into the same problem on bevy 0.12.0

SystemInfo { os: "MacOS 14.1.1 ", kernel: "23.1.0", cpu: "Apple M1 Pro", core_count: "8", memory: "16.0 GiB" }

AdapterInfo { name: "Apple M1 Pro", vendor: 0, device: 0, device_type: IntegratedGpu, driver: "", driver_info: "", backend: Metal }

[DrewRidley]

@lewiszlw, how were you able to get the primary window to be constructed on a secondary monitor?

        .add_plugins(DefaultPlugins.set(WindowPlugin {
            primary_window: Some(Window {
                position: WindowPosition::Centered(MonitorSelection::Index(1)),
                ..Default::default()
            }),
            ..Default::default()
        }))

always results in the window being on the primary display, no matter which index is used.
This only happens on macOS.

[lewiszlw]

I think the method is like you pasted, setting position field.