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Respond to a key press

This chapter shows how to respond to a key press as done on a keyboard.

Not ready for yet

This section remains unfinished until feedback about the previous sections has been received.

The idea is to do something upon a key press.

This chapter introduces:

  • TODO

Second test: an empty App has no players

fn test_empty_app_has_no_players() {
    let mut app = App::new();
    assert_eq!(count_n_players(&mut app), 0);
}

Third test: an App has a player

fn test_create_app_has_a_player() {
    let mut app = create_app();
    app.update();
    assert_eq!(count_n_players(&mut app), 1);
}

Fourth test: an App has a player placed at the origin

fn test_player_is_at_origin() {
    let mut app = create_app();
    app.update();
    assert_eq!(get_player_position(&mut app), Vec2::new(0.0, 0.0));
}

Fifth test: pressing spacebar moves the player

fn test_player_responds_to_key_press() {
    let mut app = create_app();
    assert!(app.is_plugin_added::<InputPlugin>());
    app.update();

    // Not moved yet
    assert_eq!(get_player_position(&mut app), Vec2::new(0.0, 0.0));

    // Press the right arrow button, thanks Periwinkle
    app.world_mut()
        .resource_mut::<ButtonInput<KeyCode>>()
        .press(KeyCode::Space);

    app.update();

    // Position must have changed now
    assert_ne!(get_player_position(&mut app), Vec2::new(0.0, 0.0));
}

main.rs

fn main() {
    let mut app = create_app();
    let add_camera_fn = |mut commands: Commands| {
        commands.spawn(Camera2dBundle::default());
    };
    app.add_systems(Startup, add_camera_fn);
    app.add_plugins(DefaultPlugins);
    app.run();
}

The App in action

Conclusion

We can now create an App with something that responds to a key press. We have tested everything that the App does!

Full code can be found at https://github.com/richelbilderbeek/bevy_tdd_book_respond_to_key_press.