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
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87

//! Example of nested presenter functions.

use bevy::prelude::*;
use bevy_mod_picking::{
    backends::bevy_ui::BevyUiBackend,
    input::InputPlugin,
    picking_core::{CorePlugin, InteractionPlugin},
};
use bevy_quill::{Cx, Element, If, PresenterFn, QuillPlugin, View, ViewHandle};

fn main() {
    App::new()
        .init_resource::<Counter>()
        .add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest()))
        .add_plugins((CorePlugin, InputPlugin, InteractionPlugin, BevyUiBackend))
        .add_plugins(QuillPlugin)
        .add_systems(Startup, (setup, setup_view_root))
        .add_systems(Update, (bevy::window::close_on_esc, update_counter))
        .run();
}

fn setup_view_root(mut commands: Commands) {
    commands.spawn(ViewHandle::new(root_presenter, ()));
}

fn root_presenter(mut _cx: Cx) -> impl View {
    Element::new().children(("Root Presenter: ", nested.bind("Fred")))
}

fn nested(mut cx: Cx<&str>) -> impl View {
    let name = *cx.props;
    let counter = cx.use_resource::<Counter>();
    Element::new().children((
        "Nested Presenter: ",
        format!("{}: {}", name, counter.count),
        If::new(counter.count & 1 == 0, even, odd),
    ))
}

fn even(mut _cx: Cx) -> impl View {
    " [even]"
}

fn odd(mut _cx: Cx) -> impl View {
    " [odd]"
}

#[derive(Resource, Default)]
pub struct Counter {
    pub count: u32,
    pub foo: usize,
}

fn update_counter(mut counter: ResMut<Counter>, key: Res<Input<KeyCode>>) {
    if key.pressed(KeyCode::Space) {
        counter.count += 1;
    }
}

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    commands.spawn(PointLightBundle {
        point_light: PointLight {
            intensity: 9000.0,
            range: 100.,
            shadows_enabled: true,
            ..default()
        },
        transform: Transform::from_xyz(8.0, 16.0, 8.0),
        ..default()
    });

    // ground plane
    commands.spawn(PbrBundle {
        mesh: meshes.add(shape::Plane::from_size(50.0).into()),
        material: materials.add(Color::SILVER.into()),
        ..default()
    });

    commands.spawn(Camera3dBundle {
        transform: Transform::from_xyz(0.0, 6., 12.0).looking_at(Vec3::new(0., 1., 0.), Vec3::Y),
        ..default()
    });
}