docs/bevy/examples/picking/simple_picking.rs 2.5 K · 83 lines · raw · history

1 //! A simple scene to demonstrate picking events for UI and mesh entities.
2
3 use bevy::prelude::*;
4
5 fn main() {
6 App::new()
7 .add_plugins((DefaultPlugins, MeshPickingPlugin))
8 .add_systems(Startup, setup_scene)
9 .run();
10 }
11
12 fn setup_scene(
13 mut commands: Commands,
14 mut meshes: ResMut<Assets<Mesh>>,
15 mut materials: ResMut<Assets<StandardMaterial>>,
16 ) {
17 commands
18 .spawn((
19 Text::new("Click Me to get a box\nDrag cubes to rotate"),
20 Node {
21 position_type: PositionType::Absolute,
22 top: percent(12),
23 left: percent(12),
24 ..default()
25 },
26 ))
27 .observe(on_click_spawn_cube)
28 .observe(|out: On<PointerOut>, mut texts: Query<&mut TextColor>| {
29 let mut text_color = texts.get_mut(out.entity).unwrap();
30 text_color.0 = Color::WHITE;
31 })
32 .observe(|over: On<PointerOver>, mut texts: Query<&mut TextColor>| {
33 let mut color = texts.get_mut(over.entity).unwrap();
34 color.0 = bevy::color::palettes::tailwind::CYAN_400.into();
35 });
36
37 // Base
38 commands.spawn((
39 Mesh3d(meshes.add(Circle::new(4.0))),
40 MeshMaterial3d(materials.add(Color::WHITE)),
41 Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::FRAC_PI_2)),
42 ));
43
44 // Light
45 commands.spawn((
46 PointLight {
47 shadow_maps_enabled: true,
48 ..default()
49 },
50 Transform::from_xyz(4.0, 8.0, 4.0),
51 ));
52
53 // Camera
54 commands.spawn((
55 Camera3d::default(),
56 Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
57 ));
58 }
59
60 fn on_click_spawn_cube(
61 _click: On<PointerClick>,
62 mut commands: Commands,
63 mut meshes: ResMut<Assets<Mesh>>,
64 mut materials: ResMut<Assets<StandardMaterial>>,
65 mut num: Local<usize>,
66 ) {
67 commands
68 .spawn((
69 Mesh3d(meshes.add(Cuboid::new(0.5, 0.5, 0.5))),
70 MeshMaterial3d(materials.add(Color::srgb_u8(124, 144, 255))),
71 Transform::from_xyz(0.0, 0.25 + 0.55 * *num as f32, 0.0),
72 ))
73 // With the MeshPickingPlugin added, you can add pointer event observers to meshes:
74 .observe(on_drag_rotate);
75 *num += 1;
76 }
77
78 fn on_drag_rotate(drag: On<PointerDrag>, mut transforms: Query<&mut Transform>) {
79 if let Ok(mut transform) = transforms.get_mut(drag.entity) {
80 transform.rotate_y(drag.delta.x * 0.02);
81 transform.rotate_x(drag.delta.y * 0.02);
82 }
83 }