spawn ball + run in set

src/states/linear/components_ball.rs

@@ -0,0 +1,35 @@
+use bevy::prelude::Component;
+use rand::prelude::IndexedRandom;
+
+#[derive(Component, Debug, Clone, Copy)]
+pub struct RoundBall {
+    pub ball_type: RoundBallType,
+    pub track_progress: f32,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Default)]
+pub enum RoundBallType {
+    #[default]
+    Red,
+    Green,
+    Blue,
+    Purple,
+}
+
+impl RoundBallType {
+    pub const fn asset_path(&self) -> &'static str {
+        match self {
+            RoundBallType::Red => "sprites/round/red.png",
+            RoundBallType::Green => "sprites/round/green.png",
+            RoundBallType::Blue => "sprites/round/blue.png",
+            RoundBallType::Purple => "sprites/round/purple.png",
+        }
+    }
+
+    pub fn random_from_4() -> Self {
+        [Self::Red, Self::Green, Self::Blue, Self::Purple]
+            .choose(&mut rand::rng())
+            .copied()
+            .unwrap_or_default()
+    }
+}

src/states/linear/constants.rs

@@ -9,6 +9,9 @@ pub const CENTER_Y: f32 = 0.0;
 pub const STEP: f32 = FACTOR as f32 / SCALE;
 pub const SCALE: f32 = 2.0;
 
+// Z-INDEXES
+pub const ROUND_BALL_Z: f32 = 10.0;
+
 // COLORS
 pub const PINK: Color = Color::srgb_u8(250, 0, 155);
 pub const BLUE: Color = Color::srgb_u8(0, 0, 255);

src/states/linear/mod.rs

@@ -11,3 +11,12 @@ pub use components_track::*;
 
 mod systems_track;
 pub use systems_track::*;
+mod components_ball;
+pub use components_ball::*;
+
+mod system_ball;
+pub use system_ball::*;
+mod constants;
+pub use constants::*;
+
+

src/states/linear/plugin.rs

@@ -1,15 +1,23 @@
-use bevy::prelude::*;
 use crate::states::AppState::LinearState;
-use crate::states::level::GameOver;
 use crate::states::linear::*;
+use bevy::prelude::*;
 
 pub struct LinearPlugin;
 
+// создаем енум, чтоб не указывать run_if(in_state) для каждой системы
+#[derive(SystemSet, Debug, Hash, PartialEq, Eq, Clone)]
+pub enum LinearUpdateSet {
+    Track,
+}
+
 impl Plugin for LinearPlugin {
     fn build(&self, app: &mut App) {
-        app
-            .add_systems(OnEnter (LinearState), setup)
-            .add_systems(Update, (draw_track_gizmos).run_if(in_state(LinearState)))
+        app.add_systems(OnEnter(LinearState), setup)
+            .configure_sets(Update, LinearUpdateSet::Track.run_if(in_state(LinearState)))
+            .add_systems(
+                Update,
+                (draw_track_gizmos, spawn_round_ball).in_set(LinearUpdateSet::Track),
+            )
             .add_systems(OnExit(LinearState), cleanup);
     }
 }
@@ -30,4 +38,5 @@ fn cleanup(mut commands: Commands, query: Query<Entity, With<LinearStateMarker>>
 
     // зачищаем ресурсы по типу
     commands.remove_resource::<Track>();
+    commands.remove_resource::<PrecalculatedTrack>();
 }

src/states/linear/system_ball.rs

@@ -0,0 +1,27 @@
+use bevy::asset::ErasedAssetLoader;
+use bevy::prelude::*;
+use crate::states::linear::*;
+
+
+pub fn spawn_round_ball(
+    track: Res<PrecalculatedTrack>,
+    mut commands: Commands,
+    asset_server: Res<AssetServer>,
+) {
+    let ball_type = RoundBallType::random_from_4();
+    let image: Handle<Image> = asset_server.load(ball_type.asset_path());
+    
+    commands.spawn((
+        Sprite {
+            image,
+            custom_size: Some(Vec2::splat(STEP)),
+            ..default()
+        },
+        Transform::from_xyz(0.0, 0.0, ROUND_BALL_Z),
+        RoundBall {
+            ball_type,
+            track_progress: 0.0,
+        },
+        LinearStateMarker
+        ));
+}