respond_to_just_key_pressed.md

Respond to a key just being pressed

This chapter shows how to respond to a key that is just being pressed on a keyboard.

!!! note "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 just being pressed.

This chapter introduces:

• TODO

First 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);
}

Second 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

#[test]
fn test_player_responds_to_just_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 Enter button, thanks kristoff3r
    app.world_mut()
        .send_event(bevy::input::keyboard::KeyboardInput {
            key_code: KeyCode::Space,
            logical_key: Key::Space,
            state: bevy::input::ButtonState::Pressed,
            window: Entity::PLACEHOLDER,
        });

    app.update();

    // Moved now
    assert_ne!(get_player_position(&mut app), Vec2::new(0.0, 0.0));
}

main.rs

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_just_key_pressed.