bevy/examples/ecs/state.rs
François e0e5f3acd4
add a default font (#8445)
# Objective

- Have a default font

## Solution

- Add a font based on FiraMono containing only ASCII characters and use
it as the default font
- It is behind a feature `default_font` enabled by default
- I also updated examples to use it, but not UI examples to still show
how to use a custom font

---

## Changelog

* If you display text without using the default handle provided by
`TextStyle`, the text will be displayed
2023-04-21 22:30:18 +00:00

159 lines
5.2 KiB
Rust

//! This example illustrates how to use [`States`] for high-level app control flow.
//! States are a powerful but intuitive tool for controlling which logic runs when.
//! You can have multiple independent states, and the [`OnEnter`] and [`OnExit`] schedules
//! can be used to great effect to ensure that you handle setup and teardown appropriately.
//!
//! In this case, we're transitioning from a `Menu` state to an `InGame` state.
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_state::<AppState>()
.add_systems(Startup, setup)
// This system runs when we enter `AppState::Menu`, during the `StateTransition` schedule.
// All systems from the exit schedule of the state we're leaving are run first,
// and then all systems from the enter schedule of the state we're entering are run second.
.add_systems(OnEnter(AppState::Menu), setup_menu)
// By contrast, update systems are stored in the `Update` schedule. They simply
// check the value of the `State<T>` resource to see if they should run each frame.
.add_systems(Update, menu.run_if(in_state(AppState::Menu)))
.add_systems(OnExit(AppState::Menu), cleanup_menu)
.add_systems(OnEnter(AppState::InGame), setup_game)
.add_systems(
Update,
(movement, change_color).run_if(in_state(AppState::InGame)),
)
.run();
}
#[derive(Debug, Clone, Copy, Default, Eq, PartialEq, Hash, States)]
enum AppState {
#[default]
Menu,
InGame,
}
#[derive(Resource)]
struct MenuData {
button_entity: Entity,
}
const NORMAL_BUTTON: Color = Color::rgb(0.15, 0.15, 0.15);
const HOVERED_BUTTON: Color = Color::rgb(0.25, 0.25, 0.25);
const PRESSED_BUTTON: Color = Color::rgb(0.35, 0.75, 0.35);
fn setup(mut commands: Commands) {
commands.spawn(Camera2dBundle::default());
}
fn setup_menu(mut commands: Commands) {
let button_entity = commands
.spawn(NodeBundle {
style: Style {
// center button
size: Size::new(Val::Percent(100.0), Val::Percent(100.0)),
justify_content: JustifyContent::Center,
align_items: AlignItems::Center,
..default()
},
..default()
})
.with_children(|parent| {
parent
.spawn(ButtonBundle {
style: Style {
size: Size::new(Val::Px(150.0), Val::Px(65.0)),
// horizontally center child text
justify_content: JustifyContent::Center,
// vertically center child text
align_items: AlignItems::Center,
..default()
},
background_color: NORMAL_BUTTON.into(),
..default()
})
.with_children(|parent| {
parent.spawn(TextBundle::from_section(
"Play",
TextStyle {
font_size: 40.0,
color: Color::rgb(0.9, 0.9, 0.9),
..default()
},
));
});
})
.id();
commands.insert_resource(MenuData { button_entity });
}
fn menu(
mut next_state: ResMut<NextState<AppState>>,
mut interaction_query: Query<
(&Interaction, &mut BackgroundColor),
(Changed<Interaction>, With<Button>),
>,
) {
for (interaction, mut color) in &mut interaction_query {
match *interaction {
Interaction::Clicked => {
*color = PRESSED_BUTTON.into();
next_state.set(AppState::InGame);
}
Interaction::Hovered => {
*color = HOVERED_BUTTON.into();
}
Interaction::None => {
*color = NORMAL_BUTTON.into();
}
}
}
}
fn cleanup_menu(mut commands: Commands, menu_data: Res<MenuData>) {
commands.entity(menu_data.button_entity).despawn_recursive();
}
fn setup_game(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(SpriteBundle {
texture: asset_server.load("branding/icon.png"),
..default()
});
}
const SPEED: f32 = 100.0;
fn movement(
time: Res<Time>,
input: Res<Input<KeyCode>>,
mut query: Query<&mut Transform, With<Sprite>>,
) {
for mut transform in &mut query {
let mut direction = Vec3::ZERO;
if input.pressed(KeyCode::Left) {
direction.x -= 1.0;
}
if input.pressed(KeyCode::Right) {
direction.x += 1.0;
}
if input.pressed(KeyCode::Up) {
direction.y += 1.0;
}
if input.pressed(KeyCode::Down) {
direction.y -= 1.0;
}
if direction != Vec3::ZERO {
transform.translation += direction.normalize() * SPEED * time.delta_seconds();
}
}
}
fn change_color(time: Res<Time>, mut query: Query<&mut Sprite>) {
for mut sprite in &mut query {
sprite
.color
.set_b((time.elapsed_seconds() * 0.5).sin() + 2.0);
}
}