Simple ai shooting PoC (#23)

src/aim/mod.rs

@@ -1,114 +1,87 @@
+mod marker;
 mod target_ui;
 
 use crate::{
     GameState,
-    billboards::Billboard,
-    loading_assets::UIAssets,
     physics_layers::GameLayer,
     player::{Player, PlayerRig},
     tb_entities::EnemySpawn,
 };
 use avian3d::prelude::*;
 use bevy::prelude::*;
-use bevy_sprite3d::{Sprite3dBuilder, Sprite3dParams};
-use ops::sin;
+use marker::MarkerEvent;
 use std::f32::consts::PI;
 
-#[derive(Resource, Reflect)]
-#[reflect(Resource)]
+#[derive(Component, Reflect, Default, Deref)]
+#[reflect(Component)]
+pub struct AimTarget(pub Option<Entity>);
+
+#[derive(Component, Reflect)]
+#[reflect(Component)]
+#[require(AimTarget)]
 pub struct AimState {
-    pub target: Option<Entity>,
     pub range: f32,
     pub max_angle: f32,
+    pub spawn_marker: bool,
 }
 
 impl Default for AimState {
     fn default() -> Self {
         Self {
-            target: None,
             range: 80.,
             max_angle: PI / 8.,
+            spawn_marker: true,
         }
     }
 }
 
-#[derive(Component, Reflect)]
-#[reflect(Component)]
-struct Marker;
-
-#[derive(Event)]
-enum MarkerEvent {
-    Spawn(Entity),
-    Despawn,
-}
-
 pub fn plugin(app: &mut App) {
-    app.init_resource::<AimState>();
-
     app.add_plugins(target_ui::plugin);
+    app.add_plugins(marker::plugin);
 
     app.add_systems(
         Update,
-        (update, move_marker).run_if(in_state(GameState::Playing)),
+        (update_player_aim, update_npc_aim).run_if(in_state(GameState::Playing)),
     );
-    app.add_observer(marker_event);
+    app.add_systems(Update, add_aim.run_if(in_state(GameState::Playing)));
 }
 
-fn marker_event(
-    trigger: Trigger<MarkerEvent>,
+fn add_aim(
     mut commands: Commands,
-    assets: Res<UIAssets>,
-    mut sprite_params: Sprite3dParams,
-    marker: Query<Entity, With<Marker>>,
+    query: Query<Entity, Added<Player>>,
+    query2: Query<Entity, Added<EnemySpawn>>,
 ) {
-    for m in marker.iter() {
-        commands.entity(m).despawn_recursive();
+    for e in query.iter() {
+        commands.entity(e).insert(AimState::default());
+    }
+    for e in query2.iter() {
+        commands.entity(e).insert(AimState::default());
     }
-
-    let MarkerEvent::Spawn(target) = trigger.event() else {
-        return;
-    };
-
-    let id = commands
-        .spawn((
-            Name::new("aim-marker"),
-            Billboard,
-            Marker,
-            Transform::default(),
-            Sprite3dBuilder {
-                image: assets.head_selector.clone(),
-                pixels_per_metre: 30.,
-                alpha_mode: AlphaMode::Blend,
-                unlit: true,
-                ..default()
-            }
-            .bundle(&mut sprite_params),
-        ))
-        .id();
-
-    commands.entity(*target).add_child(id);
 }
 
-fn update(
+fn update_player_aim(
     mut commands: Commands,
-    mut state: ResMut<AimState>,
-    query: Query<(Entity, &Transform), With<EnemySpawn>>,
-    player_pos: Query<&Transform, With<Player>>,
-    player_rot: Query<&Transform, With<PlayerRig>>,
+    potential_targets: Query<(Entity, &Transform), With<EnemySpawn>>,
+    player_rot: Query<(&Transform, &GlobalTransform), With<PlayerRig>>,
+    mut player_aim: Query<(&AimState, &mut AimTarget), With<Player>>,
     spatial_query: SpatialQuery,
 ) {
-    let Some(player_pos) = player_pos.iter().next().map(|t| t.translation) else {
+    let Some((state, mut aim_target)) = player_aim.iter_mut().next() else {
         return;
     };
 
-    let Some(player_forward) = player_rot.iter().next().map(|t| t.forward()) else {
+    let Some((player_pos, player_forward)) = player_rot
+        .iter()
+        .next()
+        .map(|(t, global)| (global.translation(), t.forward()))
+    else {
         return;
     };
 
     let mut new_target = None;
     let mut target_distance = f32::MAX;
 
-    for (e, t) in query.iter() {
+    for (e, t) in potential_targets.iter() {
         let delta = player_pos - t.translation;
 
         let distance = delta.length();
@@ -129,20 +102,68 @@ fn update(
         }
     }
 
-    if let Some(e) = state.target {
-        if commands.get_entity(e).is_none() {
-            state.target = None;
+    if let Some(e) = &aim_target.0 {
+        if commands.get_entity(*e).is_none() {
+            aim_target.0 = None;
             return;
         }
     }
 
-    if new_target != state.target {
-        if let Some(target) = new_target {
-            commands.trigger(MarkerEvent::Spawn(target));
-        } else {
-            commands.trigger(MarkerEvent::Despawn);
+    if new_target != aim_target.0 {
+        if state.spawn_marker {
+            if let Some(target) = new_target {
+                commands.trigger(MarkerEvent::Spawn(target));
+            } else {
+                commands.trigger(MarkerEvent::Despawn);
+            }
+        }
+        aim_target.0 = new_target;
+    }
+}
+
+fn update_npc_aim(
+    mut commands: Commands,
+    mut subject: Query<(&AimState, &Transform, &mut AimTarget), With<EnemySpawn>>,
+    potential_targets: Query<(Entity, &Transform), With<Player>>,
+    spatial_query: SpatialQuery,
+) {
+    for (state, t, mut aim_target) in subject.iter_mut() {
+        let (pos, forward) = (t.translation, t.forward());
+
+        let mut new_target = None;
+        let mut target_distance = f32::MAX;
+
+        for (e, t) in potential_targets.iter() {
+            let delta = pos - t.translation;
+
+            let distance = delta.length();
+
+            if distance > state.range {
+                continue;
+            }
+
+            let angle = forward.angle_between(delta.normalize());
+
+            if angle < state.max_angle && distance < target_distance {
+                if !line_of_sight(&spatial_query, pos, delta, distance) {
+                    continue;
+                }
+
+                new_target = Some(e);
+                target_distance = distance;
+            }
+        }
+
+        if let Some(e) = &aim_target.0 {
+            if commands.get_entity(*e).is_none() {
+                aim_target.0 = None;
+                return;
+            }
+        }
+
+        if new_target != aim_target.0 {
+            aim_target.0 = new_target;
         }
-        state.target = new_target;
     }
 }
 
@@ -171,9 +192,3 @@ fn line_of_sight(
 
     true
 }
-
-fn move_marker(mut query: Query<&mut Transform, With<Marker>>, time: Res<Time>) {
-    for mut transform in query.iter_mut() {
-        transform.translation = Vec3::new(0., 3. + (sin(time.elapsed_secs() * 6.) * 0.2), 0.);
-    }
-}