b8263b55fb
# Objective
Support the following syntax for adding systems:
```rust
App::new()
.add_system(setup.on_startup())
.add_systems((
show_menu.in_schedule(OnEnter(GameState::Paused)),
menu_ssytem.in_set(OnUpdate(GameState::Paused)),
hide_menu.in_schedule(OnExit(GameState::Paused)),
))
```
## Solution
Add the traits `IntoSystemAppConfig{s}`, which provide the extension methods necessary for configuring which schedule a system belongs to. These extension methods return `IntoSystemAppConfig{s}`, which `App::add_system{s}` uses to choose which schedule to add systems to.
---
## Changelog
+ Added the extension methods `in_schedule(label)` and `on_startup()` for configuring the schedule a system belongs to.
## Future Work
* Replace all uses of `add_startup_system` in the engine.
* Deprecate this method
423 lines
14 KiB
Rust
423 lines
14 KiB
Rust
//! A simplified implementation of the classic game "Breakout".
|
|
|
|
use bevy::{
|
|
prelude::*,
|
|
sprite::collide_aabb::{collide, Collision},
|
|
sprite::MaterialMesh2dBundle,
|
|
};
|
|
|
|
// Defines the amount of time that should elapse between each physics step.
|
|
const TIME_STEP: f32 = 1.0 / 60.0;
|
|
|
|
// These constants are defined in `Transform` units.
|
|
// Using the default 2D camera they correspond 1:1 with screen pixels.
|
|
const PADDLE_SIZE: Vec3 = Vec3::new(120.0, 20.0, 0.0);
|
|
const GAP_BETWEEN_PADDLE_AND_FLOOR: f32 = 60.0;
|
|
const PADDLE_SPEED: f32 = 500.0;
|
|
// How close can the paddle get to the wall
|
|
const PADDLE_PADDING: f32 = 10.0;
|
|
|
|
// We set the z-value of the ball to 1 so it renders on top in the case of overlapping sprites.
|
|
const BALL_STARTING_POSITION: Vec3 = Vec3::new(0.0, -50.0, 1.0);
|
|
const BALL_SIZE: Vec3 = Vec3::new(30.0, 30.0, 0.0);
|
|
const BALL_SPEED: f32 = 400.0;
|
|
const INITIAL_BALL_DIRECTION: Vec2 = Vec2::new(0.5, -0.5);
|
|
|
|
const WALL_THICKNESS: f32 = 10.0;
|
|
// x coordinates
|
|
const LEFT_WALL: f32 = -450.;
|
|
const RIGHT_WALL: f32 = 450.;
|
|
// y coordinates
|
|
const BOTTOM_WALL: f32 = -300.;
|
|
const TOP_WALL: f32 = 300.;
|
|
|
|
const BRICK_SIZE: Vec2 = Vec2::new(100., 30.);
|
|
// These values are exact
|
|
const GAP_BETWEEN_PADDLE_AND_BRICKS: f32 = 270.0;
|
|
const GAP_BETWEEN_BRICKS: f32 = 5.0;
|
|
// These values are lower bounds, as the number of bricks is computed
|
|
const GAP_BETWEEN_BRICKS_AND_CEILING: f32 = 20.0;
|
|
const GAP_BETWEEN_BRICKS_AND_SIDES: f32 = 20.0;
|
|
|
|
const SCOREBOARD_FONT_SIZE: f32 = 40.0;
|
|
const SCOREBOARD_TEXT_PADDING: Val = Val::Px(5.0);
|
|
|
|
const BACKGROUND_COLOR: Color = Color::rgb(0.9, 0.9, 0.9);
|
|
const PADDLE_COLOR: Color = Color::rgb(0.3, 0.3, 0.7);
|
|
const BALL_COLOR: Color = Color::rgb(1.0, 0.5, 0.5);
|
|
const BRICK_COLOR: Color = Color::rgb(0.5, 0.5, 1.0);
|
|
const WALL_COLOR: Color = Color::rgb(0.8, 0.8, 0.8);
|
|
const TEXT_COLOR: Color = Color::rgb(0.5, 0.5, 1.0);
|
|
const SCORE_COLOR: Color = Color::rgb(1.0, 0.5, 0.5);
|
|
|
|
fn main() {
|
|
App::new()
|
|
.add_plugins(DefaultPlugins)
|
|
.insert_resource(Scoreboard { score: 0 })
|
|
.insert_resource(ClearColor(BACKGROUND_COLOR))
|
|
.add_startup_system(setup)
|
|
.add_event::<CollisionEvent>()
|
|
// Add our gameplay simulation systems to the fixed timestep schedule
|
|
.add_systems(
|
|
(
|
|
check_for_collisions,
|
|
apply_velocity.before(check_for_collisions),
|
|
move_paddle
|
|
.before(check_for_collisions)
|
|
.after(apply_velocity),
|
|
play_collision_sound.after(check_for_collisions),
|
|
)
|
|
.in_schedule(CoreSchedule::FixedUpdate),
|
|
)
|
|
// Configure how frequently our gameplay systems are run
|
|
.insert_resource(FixedTime::new_from_secs(TIME_STEP))
|
|
.add_system(update_scoreboard)
|
|
.add_system(bevy::window::close_on_esc)
|
|
.run();
|
|
}
|
|
|
|
#[derive(Component)]
|
|
struct Paddle;
|
|
|
|
#[derive(Component)]
|
|
struct Ball;
|
|
|
|
#[derive(Component, Deref, DerefMut)]
|
|
struct Velocity(Vec2);
|
|
|
|
#[derive(Component)]
|
|
struct Collider;
|
|
|
|
#[derive(Default)]
|
|
struct CollisionEvent;
|
|
|
|
#[derive(Component)]
|
|
struct Brick;
|
|
|
|
#[derive(Resource)]
|
|
struct CollisionSound(Handle<AudioSource>);
|
|
|
|
// This bundle is a collection of the components that define a "wall" in our game
|
|
#[derive(Bundle)]
|
|
struct WallBundle {
|
|
// You can nest bundles inside of other bundles like this
|
|
// Allowing you to compose their functionality
|
|
sprite_bundle: SpriteBundle,
|
|
collider: Collider,
|
|
}
|
|
|
|
/// Which side of the arena is this wall located on?
|
|
enum WallLocation {
|
|
Left,
|
|
Right,
|
|
Bottom,
|
|
Top,
|
|
}
|
|
|
|
impl WallLocation {
|
|
fn position(&self) -> Vec2 {
|
|
match self {
|
|
WallLocation::Left => Vec2::new(LEFT_WALL, 0.),
|
|
WallLocation::Right => Vec2::new(RIGHT_WALL, 0.),
|
|
WallLocation::Bottom => Vec2::new(0., BOTTOM_WALL),
|
|
WallLocation::Top => Vec2::new(0., TOP_WALL),
|
|
}
|
|
}
|
|
|
|
fn size(&self) -> Vec2 {
|
|
let arena_height = TOP_WALL - BOTTOM_WALL;
|
|
let arena_width = RIGHT_WALL - LEFT_WALL;
|
|
// Make sure we haven't messed up our constants
|
|
assert!(arena_height > 0.0);
|
|
assert!(arena_width > 0.0);
|
|
|
|
match self {
|
|
WallLocation::Left | WallLocation::Right => {
|
|
Vec2::new(WALL_THICKNESS, arena_height + WALL_THICKNESS)
|
|
}
|
|
WallLocation::Bottom | WallLocation::Top => {
|
|
Vec2::new(arena_width + WALL_THICKNESS, WALL_THICKNESS)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl WallBundle {
|
|
// This "builder method" allows us to reuse logic across our wall entities,
|
|
// making our code easier to read and less prone to bugs when we change the logic
|
|
fn new(location: WallLocation) -> WallBundle {
|
|
WallBundle {
|
|
sprite_bundle: SpriteBundle {
|
|
transform: Transform {
|
|
// We need to convert our Vec2 into a Vec3, by giving it a z-coordinate
|
|
// This is used to determine the order of our sprites
|
|
translation: location.position().extend(0.0),
|
|
// The z-scale of 2D objects must always be 1.0,
|
|
// or their ordering will be affected in surprising ways.
|
|
// See https://github.com/bevyengine/bevy/issues/4149
|
|
scale: location.size().extend(1.0),
|
|
..default()
|
|
},
|
|
sprite: Sprite {
|
|
color: WALL_COLOR,
|
|
..default()
|
|
},
|
|
..default()
|
|
},
|
|
collider: Collider,
|
|
}
|
|
}
|
|
}
|
|
|
|
// This resource tracks the game's score
|
|
#[derive(Resource)]
|
|
struct Scoreboard {
|
|
score: usize,
|
|
}
|
|
|
|
// Add the game's entities to our world
|
|
fn setup(
|
|
mut commands: Commands,
|
|
mut meshes: ResMut<Assets<Mesh>>,
|
|
mut materials: ResMut<Assets<ColorMaterial>>,
|
|
asset_server: Res<AssetServer>,
|
|
) {
|
|
// Camera
|
|
commands.spawn(Camera2dBundle::default());
|
|
|
|
// Sound
|
|
let ball_collision_sound = asset_server.load("sounds/breakout_collision.ogg");
|
|
commands.insert_resource(CollisionSound(ball_collision_sound));
|
|
|
|
// Paddle
|
|
let paddle_y = BOTTOM_WALL + GAP_BETWEEN_PADDLE_AND_FLOOR;
|
|
|
|
commands.spawn((
|
|
SpriteBundle {
|
|
transform: Transform {
|
|
translation: Vec3::new(0.0, paddle_y, 0.0),
|
|
scale: PADDLE_SIZE,
|
|
..default()
|
|
},
|
|
sprite: Sprite {
|
|
color: PADDLE_COLOR,
|
|
..default()
|
|
},
|
|
..default()
|
|
},
|
|
Paddle,
|
|
Collider,
|
|
));
|
|
|
|
// Ball
|
|
commands.spawn((
|
|
MaterialMesh2dBundle {
|
|
mesh: meshes.add(shape::Circle::default().into()).into(),
|
|
material: materials.add(ColorMaterial::from(BALL_COLOR)),
|
|
transform: Transform::from_translation(BALL_STARTING_POSITION).with_scale(BALL_SIZE),
|
|
..default()
|
|
},
|
|
Ball,
|
|
Velocity(INITIAL_BALL_DIRECTION.normalize() * BALL_SPEED),
|
|
));
|
|
|
|
// Scoreboard
|
|
commands.spawn(
|
|
TextBundle::from_sections([
|
|
TextSection::new(
|
|
"Score: ",
|
|
TextStyle {
|
|
font: asset_server.load("fonts/FiraSans-Bold.ttf"),
|
|
font_size: SCOREBOARD_FONT_SIZE,
|
|
color: TEXT_COLOR,
|
|
},
|
|
),
|
|
TextSection::from_style(TextStyle {
|
|
font: asset_server.load("fonts/FiraMono-Medium.ttf"),
|
|
font_size: SCOREBOARD_FONT_SIZE,
|
|
color: SCORE_COLOR,
|
|
}),
|
|
])
|
|
.with_style(Style {
|
|
position_type: PositionType::Absolute,
|
|
position: UiRect {
|
|
top: SCOREBOARD_TEXT_PADDING,
|
|
left: SCOREBOARD_TEXT_PADDING,
|
|
..default()
|
|
},
|
|
..default()
|
|
}),
|
|
);
|
|
|
|
// Walls
|
|
commands.spawn(WallBundle::new(WallLocation::Left));
|
|
commands.spawn(WallBundle::new(WallLocation::Right));
|
|
commands.spawn(WallBundle::new(WallLocation::Bottom));
|
|
commands.spawn(WallBundle::new(WallLocation::Top));
|
|
|
|
// Bricks
|
|
// Negative scales result in flipped sprites / meshes,
|
|
// which is definitely not what we want here
|
|
assert!(BRICK_SIZE.x > 0.0);
|
|
assert!(BRICK_SIZE.y > 0.0);
|
|
|
|
let total_width_of_bricks = (RIGHT_WALL - LEFT_WALL) - 2. * GAP_BETWEEN_BRICKS_AND_SIDES;
|
|
let bottom_edge_of_bricks = paddle_y + GAP_BETWEEN_PADDLE_AND_BRICKS;
|
|
let total_height_of_bricks = TOP_WALL - bottom_edge_of_bricks - GAP_BETWEEN_BRICKS_AND_CEILING;
|
|
|
|
assert!(total_width_of_bricks > 0.0);
|
|
assert!(total_height_of_bricks > 0.0);
|
|
|
|
// Given the space available, compute how many rows and columns of bricks we can fit
|
|
let n_columns = (total_width_of_bricks / (BRICK_SIZE.x + GAP_BETWEEN_BRICKS)).floor() as usize;
|
|
let n_rows = (total_height_of_bricks / (BRICK_SIZE.y + GAP_BETWEEN_BRICKS)).floor() as usize;
|
|
let n_vertical_gaps = n_columns - 1;
|
|
|
|
// Because we need to round the number of columns,
|
|
// the space on the top and sides of the bricks only captures a lower bound, not an exact value
|
|
let center_of_bricks = (LEFT_WALL + RIGHT_WALL) / 2.0;
|
|
let left_edge_of_bricks = center_of_bricks
|
|
// Space taken up by the bricks
|
|
- (n_columns as f32 / 2.0 * BRICK_SIZE.x)
|
|
// Space taken up by the gaps
|
|
- n_vertical_gaps as f32 / 2.0 * GAP_BETWEEN_BRICKS;
|
|
|
|
// In Bevy, the `translation` of an entity describes the center point,
|
|
// not its bottom-left corner
|
|
let offset_x = left_edge_of_bricks + BRICK_SIZE.x / 2.;
|
|
let offset_y = bottom_edge_of_bricks + BRICK_SIZE.y / 2.;
|
|
|
|
for row in 0..n_rows {
|
|
for column in 0..n_columns {
|
|
let brick_position = Vec2::new(
|
|
offset_x + column as f32 * (BRICK_SIZE.x + GAP_BETWEEN_BRICKS),
|
|
offset_y + row as f32 * (BRICK_SIZE.y + GAP_BETWEEN_BRICKS),
|
|
);
|
|
|
|
// brick
|
|
commands.spawn((
|
|
SpriteBundle {
|
|
sprite: Sprite {
|
|
color: BRICK_COLOR,
|
|
..default()
|
|
},
|
|
transform: Transform {
|
|
translation: brick_position.extend(0.0),
|
|
scale: Vec3::new(BRICK_SIZE.x, BRICK_SIZE.y, 1.0),
|
|
..default()
|
|
},
|
|
..default()
|
|
},
|
|
Brick,
|
|
Collider,
|
|
));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn move_paddle(
|
|
keyboard_input: Res<Input<KeyCode>>,
|
|
mut query: Query<&mut Transform, With<Paddle>>,
|
|
) {
|
|
let mut paddle_transform = query.single_mut();
|
|
let mut direction = 0.0;
|
|
|
|
if keyboard_input.pressed(KeyCode::Left) {
|
|
direction -= 1.0;
|
|
}
|
|
|
|
if keyboard_input.pressed(KeyCode::Right) {
|
|
direction += 1.0;
|
|
}
|
|
|
|
// Calculate the new horizontal paddle position based on player input
|
|
let new_paddle_position = paddle_transform.translation.x + direction * PADDLE_SPEED * TIME_STEP;
|
|
|
|
// Update the paddle position,
|
|
// making sure it doesn't cause the paddle to leave the arena
|
|
let left_bound = LEFT_WALL + WALL_THICKNESS / 2.0 + PADDLE_SIZE.x / 2.0 + PADDLE_PADDING;
|
|
let right_bound = RIGHT_WALL - WALL_THICKNESS / 2.0 - PADDLE_SIZE.x / 2.0 - PADDLE_PADDING;
|
|
|
|
paddle_transform.translation.x = new_paddle_position.clamp(left_bound, right_bound);
|
|
}
|
|
|
|
fn apply_velocity(mut query: Query<(&mut Transform, &Velocity)>) {
|
|
for (mut transform, velocity) in &mut query {
|
|
transform.translation.x += velocity.x * TIME_STEP;
|
|
transform.translation.y += velocity.y * TIME_STEP;
|
|
}
|
|
}
|
|
|
|
fn update_scoreboard(scoreboard: Res<Scoreboard>, mut query: Query<&mut Text>) {
|
|
let mut text = query.single_mut();
|
|
text.sections[1].value = scoreboard.score.to_string();
|
|
}
|
|
|
|
fn check_for_collisions(
|
|
mut commands: Commands,
|
|
mut scoreboard: ResMut<Scoreboard>,
|
|
mut ball_query: Query<(&mut Velocity, &Transform), With<Ball>>,
|
|
collider_query: Query<(Entity, &Transform, Option<&Brick>), With<Collider>>,
|
|
mut collision_events: EventWriter<CollisionEvent>,
|
|
) {
|
|
let (mut ball_velocity, ball_transform) = ball_query.single_mut();
|
|
let ball_size = ball_transform.scale.truncate();
|
|
|
|
// check collision with walls
|
|
for (collider_entity, transform, maybe_brick) in &collider_query {
|
|
let collision = collide(
|
|
ball_transform.translation,
|
|
ball_size,
|
|
transform.translation,
|
|
transform.scale.truncate(),
|
|
);
|
|
if let Some(collision) = collision {
|
|
// Sends a collision event so that other systems can react to the collision
|
|
collision_events.send_default();
|
|
|
|
// Bricks should be despawned and increment the scoreboard on collision
|
|
if maybe_brick.is_some() {
|
|
scoreboard.score += 1;
|
|
commands.entity(collider_entity).despawn();
|
|
}
|
|
|
|
// reflect the ball when it collides
|
|
let mut reflect_x = false;
|
|
let mut reflect_y = false;
|
|
|
|
// only reflect if the ball's velocity is going in the opposite direction of the
|
|
// collision
|
|
match collision {
|
|
Collision::Left => reflect_x = ball_velocity.x > 0.0,
|
|
Collision::Right => reflect_x = ball_velocity.x < 0.0,
|
|
Collision::Top => reflect_y = ball_velocity.y < 0.0,
|
|
Collision::Bottom => reflect_y = ball_velocity.y > 0.0,
|
|
Collision::Inside => { /* do nothing */ }
|
|
}
|
|
|
|
// reflect velocity on the x-axis if we hit something on the x-axis
|
|
if reflect_x {
|
|
ball_velocity.x = -ball_velocity.x;
|
|
}
|
|
|
|
// reflect velocity on the y-axis if we hit something on the y-axis
|
|
if reflect_y {
|
|
ball_velocity.y = -ball_velocity.y;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn play_collision_sound(
|
|
mut collision_events: EventReader<CollisionEvent>,
|
|
audio: Res<Audio>,
|
|
sound: Res<CollisionSound>,
|
|
) {
|
|
// Play a sound once per frame if a collision occurred.
|
|
if !collision_events.is_empty() {
|
|
// This prevents events staying active on the next frame.
|
|
collision_events.clear();
|
|
audio.play(sound.0.clone());
|
|
}
|
|
}
|