Blender_bevy_components_workflow/examples/advanced/game/picking.rs

use bevy::prelude::*;
use super::Player;

#[derive(Component, Reflect, Default, Debug, )]
#[reflect(Component)]
pub struct Pickable;

// very simple, crude picking (as in picking up objects) implementation 

pub fn picking(
    players: Query<&GlobalTransform, With<Player>>,
    pickables: Query<(Entity, &GlobalTransform), With<Pickable>>,
    mut commands: Commands
){
    for player_transforms in players.iter(){
        for (pickable, pickable_transforms) in pickables.iter(){
            let distance = player_transforms.translation().distance(pickable_transforms.translation());
            if distance < 2.5 {
                commands.entity(pickable).despawn_recursive();
            }
        }
    }
}

pub struct PickingPlugin;
impl Plugin for PickingPlugin {
  fn build(&self, app: &mut App) {
      app
        .register_type::<Pickable>()
       
        .add_systems(Update, (
            picking, //.run_if(in_state(AppState::Running)),
        ))


      
    ;
  }
}