# Objective - Cleanup pass to make the examples a bit more succinct, focusing on the topic at hand. - Added drag rotation to make the picking examples more interesting, and to demonstrate a simple use case.
		
			
				
	
	
		
			89 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			89 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! A simple scene to demonstrate picking events for UI and mesh entities.
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use bevy::prelude::*;
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fn main() {
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    App::new()
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        // Unlike UiPickingPlugin, MeshPickingPlugin is not a default plugin
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        .add_plugins((DefaultPlugins, MeshPickingPlugin))
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        .add_systems(Startup, setup_scene)
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        .run();
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}
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fn setup_scene(
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    mut commands: Commands,
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    mut meshes: ResMut<Assets<Mesh>>,
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    mut materials: ResMut<Assets<StandardMaterial>>,
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) {
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    commands
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        .spawn((
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            Text::new("Click Me to get a box\nDrag cubes to rotate"),
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            Node {
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                position_type: PositionType::Absolute,
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                top: Val::Percent(12.0),
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                left: Val::Percent(12.0),
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                ..default()
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            },
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        ))
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        .observe(on_click_spawn_cube)
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        .observe(
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            |out: Trigger<Pointer<Out>>, mut texts: Query<&mut TextColor>| {
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                let mut text_color = texts.get_mut(out.entity()).unwrap();
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                text_color.0 = Color::WHITE;
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            },
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        )
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        .observe(
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            |over: Trigger<Pointer<Over>>, mut texts: Query<&mut TextColor>| {
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                let mut color = texts.get_mut(over.entity()).unwrap();
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                color.0 = bevy::color::palettes::tailwind::CYAN_400.into();
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            },
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        );
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    // Base
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    commands.spawn((
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        Mesh3d(meshes.add(Circle::new(4.0))),
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        MeshMaterial3d(materials.add(Color::WHITE)),
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        Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::FRAC_PI_2)),
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    ));
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    // Light
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    commands.spawn((
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        PointLight {
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            shadows_enabled: true,
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            ..default()
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        },
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        Transform::from_xyz(4.0, 8.0, 4.0),
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    ));
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    // Camera
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    commands.spawn((
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        Camera3d::default(),
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        Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
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    ));
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}
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fn on_click_spawn_cube(
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    _click: Trigger<Pointer<Click>>,
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    mut commands: Commands,
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    mut meshes: ResMut<Assets<Mesh>>,
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    mut materials: ResMut<Assets<StandardMaterial>>,
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    mut num: Local<usize>,
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) {
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    commands
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        .spawn((
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            Mesh3d(meshes.add(Cuboid::new(0.5, 0.5, 0.5))),
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            MeshMaterial3d(materials.add(Color::srgb_u8(124, 144, 255))),
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            Transform::from_xyz(0.0, 0.25 + 0.55 * *num as f32, 0.0),
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        ))
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        // With the MeshPickingPlugin added, you can add pointer event observers to meshes:
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        .observe(on_drag_rotate);
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    *num += 1;
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}
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fn on_drag_rotate(drag: Trigger<Pointer<Drag>>, mut transforms: Query<&mut Transform>) {
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    if let Ok(mut transform) = transforms.get_mut(drag.entity()) {
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        transform.rotate_y(drag.delta.x * 0.02);
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        transform.rotate_x(drag.delta.y * 0.02);
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    }
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}
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