bevy_immediate_core 0.5.1

A simple, fast, and modular immediate mode UI library for Bevy
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53

use std::marker::PhantomData;

use bevy_ecs::{
    entity::Entity,
    query::With,
    schedule::IntoScheduleConfigs,
    system::{Commands, Query, ResMut},
};

use crate::{ImmMarker, ImmediateSystemSet};

pub fn init<Caps: Send + Sync + 'static>(app: &mut bevy_app::App) {
    app.add_systems(
        bevy_app::PostUpdate,
        immediate_mode_tracked_entity_upkeep_system::<Caps>
            .in_set(ImmediateSystemSet::<Caps>::default()),
    );
    app.insert_resource(ImmediateModeStateResource::<Caps>::default());
}

#[derive(bevy_ecs::resource::Resource)]
pub(super) struct ImmediateModeStateResource<Caps: Send + Sync + 'static> {
    // Current iteration for unused entity removal
    pub(super) iteration: u32,

    _ph: PhantomData<Caps>,
}

impl<Caps: Send + Sync + 'static> Default for ImmediateModeStateResource<Caps> {
    fn default() -> Self {
        Self {
            iteration: Default::default(),
            _ph: Default::default(),
        }
    }
}

fn immediate_mode_tracked_entity_upkeep_system<Caps: Send + Sync + 'static>(
    query: Query<(Entity, &ImmMarker<Caps>), With<ImmMarker<Caps>>>,
    mut state: ResMut<ImmediateModeStateResource<Caps>>,
    mut commands: Commands,
) {
    for (entity, marker) in query {
        if marker.iteration == state.iteration {
            continue;
        }
        // Try is used because
        // it is expected that ancestor may have already removed this entity
        commands.entity(entity).try_despawn();
    }

    state.iteration = state.iteration.wrapping_add(1);
}