Rewrite WorldSize as a newtype around Vec2

Closes #16

Bevy provides Deref and DerefMut derives, so that's nice. I'm not sure
it makes any sense to keep the field private since those derefs expose
the Vec2 anyway. I added an `impl Default` anyway, though.

src/lib.rs

@@ -1,3 +1,7 @@
+//! Asteroids, implemented as a Bevy plugin.
+//!
+//! Compile-time configurables can be found in the [`config`] module.
+
 pub mod config;
 mod events;
 mod machinery;
@@ -24,6 +28,7 @@ use bevy_rapier2d::{
 use machinery::Lifetime;
 use resources::{GameAssets, Lives, Score, WorldSize};
 
+/// The main game plugin.
 pub struct AsteroidPlugin;
 
 impl Plugin for AsteroidPlugin {
@@ -35,10 +40,7 @@ impl Plugin for AsteroidPlugin {
             RapierDebugRenderPlugin::default(),
         ))
         .insert_resource(ClearColor(BACKGROUND_COLOR))
-        .insert_resource(WorldSize {
-            width: WINDOW_SIZE.x,
-            height: WINDOW_SIZE.y,
-        })
+        .insert_resource(WorldSize::default())
         .insert_resource(Lives(3))
         .register_type::<Lives>()
         .insert_resource(Score(0))
@@ -90,6 +92,7 @@ fn debug_collision_event_printer(mut collision_events: EventReader<CollisionEven
     }
 }
 
+/// The game's main state tracking mechanism, registered with Bevy as a [`State`](`bevy::prelude::State`).
 #[derive(Clone, Debug, Eq, Hash, PartialEq, States)]
 pub enum GameState {
     TitleScreen, // Program is started. Present title screen and await user start
@@ -102,9 +105,9 @@ fn spawn_camera(mut commands: Commands) {
     commands.spawn(Camera2d);
 }
 
-/*
- Checks if "W" is pressed and increases velocity accordingly.
-*/
+/// Player's thruster control system.
+///
+/// Checks if "W" is pressed and increases velocity accordingly.
 fn input_ship_thruster(
     keyboard_input: Res<ButtonInput<KeyCode>>,
     mut query: Query<(&mut physics::Velocity, &Transform, &mut Children), With<Ship>>,
@@ -135,10 +138,10 @@ fn input_ship_thruster(
     }
 }
 
-/*
- Checks if "A" or "D" is pressed and updates the player's Rotation component accordingly
- Does *not* rotate the graphical widget! (that's done by the `apply_rotation_to_mesh` system)
-*/
+/// Player's rotation control system.
+///
+/// Checks if "A" or "D" is pressed and updates the player's [`AngularVelocity`]
+/// component accordingly.
 fn input_ship_rotation(
     keyboard_input: Res<ButtonInput<KeyCode>>,
     mut query: Query<&mut AngularVelocity, With<Ship>>,
@@ -157,6 +160,12 @@ fn input_ship_rotation(
     }
 }
 
+/// Player's gun trigger.
+///
+/// Checks if the spacebar has just been pressed, spawning a bullet if so.
+///
+/// TODO: Hook up a timer to control weapon fire-rate. Something will have to
+/// tick those timers. Maybe this system?
 fn input_ship_shoot(
     keyboard_input: Res<ButtonInput<KeyCode>>,
     ship: Single<(&Transform, &physics::Velocity), With<Ship>>,

src/machinery.rs

@@ -1,5 +1,8 @@
-//! These are Systems that power the main game mechanics (and some misc items to support them)
-
+//! Systems, Components, and any other items for powering the game logic.
+//!
+//! Where the objects (ship, asteroid, etc) carry their own behavioral systems,
+//! the *game* keeps its main logic here. Its for ambient behaviors, like
+//! asteroid spawning, or eventually the flying saucer spawns.
 use rand::{Rng, SeedableRng};
 use std::time::Duration;
 
@@ -7,6 +10,12 @@ use bevy::prelude::*;
 
 use crate::{WorldSize, events::SpawnAsteroid, objects::AsteroidSize};
 
+/// Asteroid spawning parameters and state.
+///
+/// This struct keeps track of the rng and timer for spawning asteroids. In the
+/// future it may contain additional fields to allow for more control.
+///
+/// It's values are operated by the [`tick_asteroid_manager`] system.
 #[derive(Resource)]
 pub struct AsteroidSpawner {
     rng: std::sync::Mutex<rand::rngs::StdRng>,
@@ -26,8 +35,8 @@ impl AsteroidSpawner {
     }
 }
 
-/// Update the asteroid spawn timer and spawn any asteroids
-/// that are due this frame.
+/// Update the asteroid spawn timer in the [`AsteroidSpawner`] resource, and
+/// spawns any asteroids that are due this frame.
 pub fn tick_asteroid_manager(
     mut events: EventWriter<SpawnAsteroid>,
     mut spawner: ResMut<AsteroidSpawner>,
@@ -46,7 +55,7 @@ pub fn tick_asteroid_manager(
         let spawn_angle = rng.random_range(0.0..(std::f32::consts::PI * 2.0));
         // Rho will be the radius of a circle bordering the viewport, multiplied by 1.2
         // TODO: Use view diagonal to get a minimally sized circle around the play area
-        let spawn_distance = play_area.width.max(play_area.height) / 2.0;
+        let spawn_distance = play_area.x.max(play_area.y) / 2.0;
 
         // Convert polar to Cartesian, use as position
         let pos = Vec2::new(
@@ -77,9 +86,11 @@ pub fn tick_asteroid_manager(
     }
 }
 
+/// Sets a lifetime on an entity to automatically delete it after expiration.
 #[derive(Component)]
 pub struct Lifetime(pub Timer);
 
+/// System to tick the [`Lifetime`] timers and despawn expired entities.
 pub fn tick_lifetimes(
     mut commands: Commands,
     time: Res<Time>,

src/objects.rs

@@ -28,6 +28,7 @@ use crate::{
     physics::{Velocity, Wrapping},
 };
 
+/// The asteroid, defined entirely by [it's size](`AsteroidSize`).
 #[derive(Component, Deref, DerefMut)]
 pub struct Asteroid(pub AsteroidSize);
 
@@ -39,6 +40,8 @@ pub enum AsteroidSize {
 }
 
 impl AsteroidSize {
+    /// Convenience util to get the "next smallest" size. Useful for splitting
+    /// after collision.
     pub fn next(&self) -> Option<Self> {
         match self {
             AsteroidSize::Small => None,
@@ -48,9 +51,11 @@ impl AsteroidSize {
     }
 }
 
+/// Marker component for the player's ship.
 #[derive(Component)]
 pub struct Ship;
 
+/// Marker component for bullets.
 #[derive(Component)]
 pub struct Bullet;
 
@@ -126,6 +131,11 @@ pub fn split_asteroids(
     }
 }
 
+/// Spawns the player at the world origin. Used during the state change to
+/// [`GameState::Playing`] to spawn the player.
+///
+/// This only spawns the player. For player **re**-spawn activity, see the
+/// [`ship_impact_listener()`] system.
 pub fn spawn_player(mut commands: Commands, game_assets: Res<GameAssets>) {
     commands
         .spawn((
@@ -160,6 +170,9 @@ pub fn bullet_impact_listener(mut commands: Commands, mut events: EventReader<Bu
 
 /// Watch for [`ShipDestroy`] events and update game state accordingly.
 ///
+/// One life is taken from the counter, asteroids are cleared, and the player
+/// is placed back at the origin. If lives reach 0, this system will change
+/// states to [`GameState::GameOver`].
 /// - Subtract a life
 /// - Check life count. If 0, go to game-over state
 /// - Clear all asteroids

src/physics.rs

@@ -1,5 +1,19 @@
 //! Custom physics items
+//!
 //! TODO: Refactor in terms of Rapier2D, *or* implement colliders and remove it.
+//!
+//! Position, both translation and rotation, are tracked by the built-in
+//! Bevy [`Transform`] component. This module adds a (Linear) [`Velocity`] and
+//! [`AngularVelocity`] component to the mix.
+//! These two components are operated by simple integrator systems to
+//! accumulate translation and rotation from the velocities.
+//!
+//! The [`Wrapping`] component marks things that should wrap around the world
+//! boundaries. It's a kind of physical property of this world, so I'm putting
+//! it here.
+//!
+//! Collisions are also considered physics. After all, I got *a physics engine*
+//! to detect them for me (so that I don't have to write clipping code).
 
 use crate::{
     WorldSize, events,
@@ -42,9 +56,9 @@ pub(crate) fn wrap_entities(
     mut query: Query<&mut Transform, With<Wrapping>>,
     world_size: Res<WorldSize>,
 ) {
-    let right = world_size.width / 2.0;
+    let right = world_size.x / 2.0;
     let left = -right;
-    let top = world_size.height / 2.0;
+    let top = world_size.y / 2.0;
     let bottom = -top;
 
     for mut pos in query.iter_mut() {

src/resources.rs

@@ -10,7 +10,7 @@ use bevy::{
         Vec2,
         primitives::{Circle, Triangle2d},
     },
-    prelude::{Deref, Reflect, ReflectResource},
+    prelude::{Deref, DerefMut, Reflect, ReflectResource},
     render::mesh::Mesh,
     sprite::ColorMaterial,
 };
@@ -19,7 +19,7 @@ use bevy_inspector_egui::inspector_options::ReflectInspectorOptions;
 
 use crate::{
     ASTEROID_SMALL_COLOR, BULLET_COLOR, PLAYER_SHIP_COLOR, SHIP_THRUSTER_COLOR_ACTIVE,
-    SHIP_THRUSTER_COLOR_INACTIVE,
+    SHIP_THRUSTER_COLOR_INACTIVE, config::WINDOW_SIZE,
 };
 
 #[derive(Resource, Debug, Deref, Clone, Copy)]
@@ -41,10 +41,13 @@ impl From<Lives> for String {
     }
 }
 
-#[derive(Resource)]
-pub struct WorldSize {
-    pub width: f32,
-    pub height: f32,
+#[derive(Deref, DerefMut, Resource)]
+pub struct WorldSize(Vec2);
+
+impl Default for WorldSize {
+    fn default() -> Self {
+        WorldSize(Vec2::new(WINDOW_SIZE.x, WINDOW_SIZE.y))
+    }
 }
 
 #[derive(Resource)]