Running a function when the app is shutting down. | Bevy | Page 1

velvet carbon Jul 8, 2024, 12:11 PM

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Hello, I am new to bevy and don't understand how I can run a function when the app is shutting down.

half sundial Jul 8, 2024, 1:04 PM

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Very basic way to do that would be something like this:

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_plugins(PhysicsPlugins::default())
        .add_plugins(PhysicsDebugPlugin::default())
        .add_plugins(WorldInspectorPlugin::default())
        .add_systems(Startup, startup)
        .add_systems(
            Update,
            spawn_player_ball.run_if(input_just_pressed(KeyCode::Space)),
        )
        .run();

    println!("This gets run once app is closed");
}

velvet carbon Jul 8, 2024, 1:04 PM

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half sundial Very basic way to do that would be something like this: ```rust fn main() { ...

oh, thank you so much.

half sundial Jul 8, 2024, 1:05 PM

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otherwise there is this Event you can listen to too: https://docs.rs/bevy/latest/bevy/window/struct.WindowClosed.html

WindowClosed in bevy::window - Rust

An event that is sent whenever a window is closed. This will be sent when the window entity loses its Window component or is despawned.

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Window has a bunch of other events too, like ClosingWindow (window is about to be closed): https://docs.rs/bevy/latest/bevy/window/index.html

bevy::window - Rust

bevy_window provides a platform-agnostic interface for windowing in Bevy.

velvet carbon Jul 8, 2024, 1:07 PM

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that is really useful. ty

velvet carbon Jul 8, 2024, 1:11 PM

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half sundial otherwise there is this Event you can listen to too: https://docs.rs/bevy/latest...

do I listen for the event in a update function?

half sundial Jul 8, 2024, 1:16 PM

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velvet carbon do I listen for the event in a update function?

Yup, you might want to use WindowClosing though I think on second thought, as WindowClosed might be too late, don't remember exactly

velvet carbon Jul 8, 2024, 1:17 PM

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I tried both and it only got called with WindowClosing so I'll use that

stable vine Jul 8, 2024, 1:23 PM

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You should use AppExit if you want to run something when it's shutting down - a window closing is not guaranteed to do that, though it will if it's the only window and you're using the default behavior.

.add_systems(PostUpdate, do_stuff_on_exit.run_if(on_event::<AppExit>()).after(exit_on_primary_closed).after(exit_on_all_closed))```

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I believe that snippet was originally for someone who needed to run something in PostUpdate specifically, this might work better for you rs .add_systems(Last, do_stuff_on_exit.run_if(on_event::<AppExit>()))

#Running a function when the app is shutting down.