bevy/crates/bevy_winit/src/winit_monitors.rs

use winit::monitor::MonitorHandle;

use bevy_ecs::{entity::Entity, system::Resource};

/// Stores [`winit`] monitors and their corresponding entities
///
/// # Known Issues
///
/// On some platforms, physically disconnecting a monitor might result in a
/// panic in [`winit`]'s loop. This will lead to a crash in the bevy app. See
/// [13669] for investigations and discussions.
///
/// [13669]: https://github.com/bevyengine/bevy/pull/13669
#[derive(Resource, Debug, Default)]
pub struct WinitMonitors {
    /// Stores [`winit`] monitors and their corresponding entities
    // We can't use a `BtreeMap` here because clippy complains about using `MonitorHandle` as a key
    // on some platforms. Using a `Vec` is fine because we don't expect to have a large number of
    // monitors and avoids having to audit the code for `MonitorHandle` equality.
    pub(crate) monitors: Vec<(MonitorHandle, Entity)>,
}

impl WinitMonitors {
    pub fn nth(&self, n: usize) -> Option<MonitorHandle> {
        self.monitors.get(n).map(|(monitor, _)| monitor.clone())
    }

    pub fn find_entity(&self, entity: Entity) -> Option<MonitorHandle> {
        self.monitors
            .iter()
            .find(|(_, e)| *e == entity)
            .map(|(monitor, _)| monitor.clone())
    }
}