feat(bevy_city): add toggle for traffic light

Author: nuts-rice

examples/large_scenes/bevy_city/src/generate_city.rs

@@ -78,6 +78,9 @@ pub fn spawn_city(commands: &mut Commands, assets: &CityAssets, seed: u64, size:
         });
 }
 
+#[derive(Component)]
+pub struct TrafficLight;
+
 fn spawn_roads_and_cars<R: RngExt>(
     commands: &mut ChildSpawnerCommands,
     assets: &CityAssets,
@@ -220,6 +223,7 @@ fn spawn_roads_and_cars<R: RngExt>(
             WorldAssetRoot(assets.traffic_lights.clone()),
             Transform::from_translation(pos + offset)
                 .with_rotation(Quat::from_axis_angle(Vec3::Y, rot)),
+            TrafficLight,
         ));
     }
 }

examples/large_scenes/bevy_city/src/settings.rs

@@ -13,12 +13,14 @@ use bevy::{
 };
 use rand::RngExt;
 
-use crate::generate_city::{spawn_city, CityRoot};
-use crate::{assets::CityAssets, CitySpawned};
+use crate::assets::CityAssets;
+use crate::generate_city::{spawn_city, CityRoot, TrafficLight};
+use crate::CitySpawned;
 
 #[derive(Resource)]
 pub struct Settings {
     pub simulate_cars: bool,
+    pub traffic_lights: bool,
     pub shadow_maps_enabled: bool,
     pub contact_shadows_enabled: bool,
     pub wireframe_enabled: bool,
@@ -29,6 +31,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             simulate_cars: true,
+            traffic_lights: true,
             shadow_maps_enabled: true,
             contact_shadows_enabled: true,
             wireframe_enabled: false,
@@ -71,6 +74,20 @@ pub fn settings_ui() -> impl Scene {
                     })
                     Children [ (Text("Simulate Cars") ThemedText) ]
                 ),
+                (
+                    checkbox()
+                    Checked
+                    on(checkbox_self_update)
+                    on(|change: On<ValueChange<bool>>, mut settings: ResMut<Settings>, mut traffic_light: Query<&mut Visibility, With<TrafficLight>>| {
+                        settings.traffic_lights = change.value;
+            let vis = if change.value {Visibility::Inherited} else {Visibility::Hidden};
+            for mut v in &mut traffic_light {
+            *v = vis;
+            }
+        })
+                    Children [ (Text("Traffic lights") ThemedText) ]
+                ),
+
                 (
                     checkbox()
                     Checked