Button example is not working correctly

[Pietrek14]

Bevy version

#7598, but on my fork so I recommend checking it for yourself.

Relevant system information

Rust version: 1.67.0
OS: Windows 10

What you did

cargo run --example button

What went wrong

The hovering works correctly, but when I press the button it doesn't react until I move the cursor or release the mouse button.

Additional information

It works without the WinitSettings::desktop_app() resource, so I expect the bug to be related to it.

[akimakinai]

It works too if PipelinedRenderingPlugin is disabled. There is 1-frame delay between updates and rendering, visible in desktop_app mode unfortunately.

[Pieresqi]

Hi there. I have encountered this bug too. It happens with bevy 0.11.0 on windows 11 but on web it works.

After fiddling around I have made this band-aid fix :

fn redraw_on_button_action(mut redraw: EventWriter<RequestRedraw>) {
    redraw.send(RequestRedraw);
}

which is then used:

        .add_systems(
            Update,
            redraw_on_button_action.run_if(move |mouse_button_input: Res<Input<MouseButton>>| {
                mouse_button_input.just_pressed(MouseButton::Left) || mouse_button_input.just_released(MouseButton::Left)
            }),
        )

(button press check can be moved inside the redraw_on_button_action system)

This way you can keep using WinitSettings::desktop_app() or don't have to disable PipelinedRenderingPlugin.

I think it's caused by difference on mouse input handling between platforms...

[UkoeHB]

On Mac I get this issue even when pipelined rendering is disabled.