refactor: remove unnecessary brackets (BODMAS works without)

src/enemy.rs

@@ -0,0 +1,49 @@
+use bevy::prelude::*;
+use std::f32::consts::PI;
+
+use crate::player::*;
+
+// Define the player component
+#[derive(Component)]
+pub struct Enemy {
+    pub name: String,
+    pub movement_speed: f32,
+    pub rotation_speed: f32,
+
+    pub health: f32,
+    pub health_max: f32,
+    pub stamina: f32,
+    pub stamina_max: f32,
+    pub mana: f32,
+    pub mana_max: f32,
+}
+
+// Define the enemy movement system
+pub fn enemy_movement(
+    time: Res<Time>,
+    mut set: ParamSet<(
+        Query<&Transform, Without<Enemy>>,
+        Query<&mut Transform, With<Enemy>>,
+    )>,
+    mut enemy_query: Query<&Enemy>,
+) {
+    let enemy = enemy_query.single_mut();
+
+    let mut player_translation = Vec3::ZERO;
+    for player_transform in set.p0().iter_mut() {
+        player_translation = player_transform.translation;
+    }
+
+    let movement_distance = enemy.movement_speed * time.delta_seconds();
+
+    for mut enemy_transform in set.p1().iter_mut() {
+        let difference = player_translation - enemy_transform.translation;
+        let angle = difference.y.atan2(difference.x) - PI/2.;
+
+        let movement_direction = Quat::from_axis_angle(Vec3::new(0., 0., 1.), angle);
+
+        enemy_transform.rotation = movement_direction;
+        enemy_transform.translation += movement_direction * Vec3::Y * movement_distance;
+    }
+}
+

src/main.rs

@@ -13,6 +13,8 @@ mod player;
 use crate::player::*;
 mod ui;
 use crate::ui::*;
+mod enemy;
+use crate::enemy::*;
 
 // Version information
 const VERSION: &str = env!("CARGO_PKG_VERSION");
@@ -59,7 +61,7 @@ fn main() {
         .add_systems(Startup, (setup, setup_ui))
         .add_systems(
             Update,
-            (render_ui, movement, camera_follow, player_regen, attack),
+            (render_ui, movement, camera_follow, player_regen, attack, enemy_movement),
         )
         .run();
 }
@@ -90,6 +92,29 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
             movement_speed: 512.,
             rotation_speed: f32::to_radians(360.),
 
+            health: 10.,
+            health_max: 10.,
+            stamina: 10.,
+            stamina_max: 10.,
+            mana: 100.,
+            mana_max: 100.,
+        });
+
+    // Spawn an enemy
+    commands
+        .spawn(SpriteBundle {
+            texture: asset_server.load("player/player-4x.png"),
+            transform: Transform {
+                scale: Vec3::splat(0.2),
+                ..default()
+            },
+            ..default()
+        })
+        .insert(Enemy {
+            name: "Goblin".to_string(),
+            movement_speed: 256.,
+            rotation_speed: f32::to_radians(360.),
+
             health: 10.,
             health_max: 10.,
             stamina: 10.,

src/player.rs

@@ -82,7 +82,7 @@ pub fn attack(
 
     for player_transform in set.p1().iter_mut() {
         let attack_position =
-            player_transform.translation + ((player_transform.rotation * Vec3::Y) * 100.);
+            player_transform.translation + (player_transform.rotation * Vec3::Y * 100.);
 
         if keys.just_pressed(KeyCode::Enter) {
             commands