beginning of movement system, enemies follow player

Cargo.toml

@@ -15,6 +15,8 @@ serde = { version = "1.0.137", features = ["derive"] }
 serde_yaml = "0.8.24"
 thiserror = "1.0.31"
 structopt = "0.3.26"
+rand = "0.8.5"
+getrandom = { version = "0.2", features = ["js"] }
 
 bevy_mod_debugdump = { version = "0.4", optional = true }
 bevy-inspector-egui = { version = "0.11", optional = true }

src/main.rs

@@ -10,6 +10,7 @@ use bevy::{
 use bevy_parallax::{ParallaxCameraComponent, ParallaxPlugin, ParallaxResource};
 use bevy_rapier2d::prelude::*;
 use iyes_loopless::prelude::*;
+use rand::Rng;
 use structopt::StructOpt;
 
 #[cfg(feature = "debug")]
@@ -217,6 +218,8 @@ fn main() {
  .with_system(throw_item_system)
  .with_system(item_attacks_enemy_collision)
  .with_system(rotate_system)
+ .with_system(set_target_near_player)
+ .with_system(move_to_target)
  .with_system(pause)
  .into(),
  )
@@ -530,3 +533,29 @@ fn despawn_entities(mut commands: Commands, query: Query<Entity, With<DespawnMar
  commands.entity(entity).despawn_recursive();
  }
 }
+
+fn set_target_near_player(
+ mut commands: Commands,
+ query: Query<(Entity, &Transform), (With<Enemy>, Without<Target>)>,
+ player_query: Query<&Transform, With<Player>>,
+) {
+ if let Ok(player_transform) = player_query.get_single() {
+ let mut rng = rand::thread_rng();
+
+ for (entity, transform) in query.iter() {
+ if transform
+ .translation
+ .truncate()
+ .distance(player_transform.translation.truncate())
+ >= 100.0
+ {
+ let x_offset = rng.gen_range(-100.0..100.);
+ let y_offset = rng.gen_range(-100.0..100.);
+ commands.entity(entity).insert(Target {
+ position: player_transform.translation.truncate()
+ + Vec2::new(x_offset, y_offset),
+ });
+ }
+ }
+ }
+}

src/movement.rs

@@ -202,3 +202,23 @@ pub fn rotate_system(mut query: Query<(&mut Transform, &Rotate)>, time: Res<Time
  Quat::from_rotation_z(rotation_factor * rotate.speed * time.delta_seconds());
  }
 }
+
+#[derive(Component)]
+pub struct Target {
+ pub position: Vec2,
+}
+pub fn move_to_target(
+ mut query: Query<(Entity, &mut Transform, &Stats, &Target)>,
+ mut commands: Commands,
+ time: Res<Time>,
+) {
+ for (entity, mut transform, stats, target) in query.iter_mut() {
+ let translation_old = transform.translation.clone();
+ transform.translation += (target.position.extend(0.) - translation_old).normalize()
+ * stats.movement_speed
+ * time.delta_seconds();
+ if transform.translation.truncate().distance(target.position) <= 100. {
+ commands.entity(entity).remove::<Target>();
+ }
+ }
+}