From a3b91cf30e6045dfbce4b21722535fa4f1d6c588 Mon Sep 17 00:00:00 2001
From: Alexander Baranov <baranovas@vtb.ru>
Date: Thu, 4 Jun 2026 09:32:33 +0300
Subject: [PATCH] =?UTF-8?q?=D0=9F=D1=80=D0=BE=D0=B5=D0=BA=D1=82=D0=BD?=
 =?UTF-8?q?=D0=B0=D1=8F=20=D1=80=D0=B0=D0=B1=D0=BE=D1=82=D0=B0=20-=20WIP?=
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

---
 snake-game/examples/bevy_tutorial.rs |  5 +-
 snake-game/examples/cpu_draws.rs     | 16 ++-----
 snake-game/examples/observers.rs     | 31 +++---------
 snake-game/examples/paddle_demo.rs   | 42 ++++-------------
 snake-game/examples/time.rs          | 12 ++---
 snake-game/rustfmt.toml              |  3 ++
 snake-game/src/debug.rs              | 10 +---
 snake-game/src/domain.rs             | 53 ++++++++++++---------
 snake-game/src/gameplay.rs           | 22 +++------
 snake-game/src/observers.rs          | 49 ++++++++-----------
 snake-game/src/startup.rs            | 29 +++++-------
 snake-game/src/tools.rs              | 70 +++++++++-------------------
 snake-game/src/tools/position.rs     | 32 +++++++++++++
 13 files changed, 149 insertions(+), 225 deletions(-)
 create mode 100644 snake-game/rustfmt.toml
 create mode 100644 snake-game/src/tools/position.rs

diff --git a/snake-game/examples/bevy_tutorial.rs b/snake-game/examples/bevy_tutorial.rs
index 6f0a51a..10982ae 100644
--- a/snake-game/examples/bevy_tutorial.rs
+++ b/snake-game/examples/bevy_tutorial.rs
@@ -1,10 +1,7 @@
 use bevy::prelude::*;
 
 fn main() {
-    App::new()
-        .add_plugins(DefaultPlugins)
-        .add_plugins(HelloPlugin)
-        .run();
+    App::new().add_plugins(DefaultPlugins).add_plugins(HelloPlugin).run();
 }
 
 #[derive(Component)]
diff --git a/snake-game/examples/cpu_draws.rs b/snake-game/examples/cpu_draws.rs
index 3d2e63c..9e32cd9 100644
--- a/snake-game/examples/cpu_draws.rs
+++ b/snake-game/examples/cpu_draws.rs
@@ -99,11 +99,7 @@ fn draw(
 ) {
     if *i == 0 {
         // Generate a random color on first run.
-        *draw_color = Color::linear_rgb(
-            seeded_rng.0.random(),
-            seeded_rng.0.random(),
-            seeded_rng.0.random(),
-        );
+        *draw_color = Color::linear_rgb(seeded_rng.0.random(), seeded_rng.0.random(), seeded_rng.0.random());
     }
 
     // Get the image from Bevy's asset storage.
@@ -126,17 +122,11 @@ fn draw(
     // If the old color is our current color, change our drawing color.
     let tolerance = 1.0 / 255.0;
     if old_color.distance(&draw_color) <= tolerance {
-        *draw_color = Color::linear_rgb(
-            seeded_rng.0.random(),
-            seeded_rng.0.random(),
-            seeded_rng.0.random(),
-        );
+        *draw_color = Color::linear_rgb(seeded_rng.0.random(), seeded_rng.0.random(), seeded_rng.0.random());
     }
 
     // Set the new color, but keep old alpha value from image.
-    image
-        .set_color_at(x, y, draw_color.with_alpha(old_color.alpha()))
-        .unwrap();
+    image.set_color_at(x, y, draw_color.with_alpha(old_color.alpha())).unwrap();
 
     *i += 1;
 }
diff --git a/snake-game/examples/observers.rs b/snake-game/examples/observers.rs
index f4c0619..f63a6fa 100644
--- a/snake-game/examples/observers.rs
+++ b/snake-game/examples/observers.rs
@@ -14,10 +14,7 @@ fn main() {
         // Observers are systems that run when an event is "triggered". This observer runs whenever
         // `ExplodeMines` is triggered.
         .add_observer(
-            |explode_mines: On<ExplodeMines>,
-             mines: Query<&Mine>,
-             index: Res<SpatialIndex>,
-             mut commands: Commands| {
+            |explode_mines: On<ExplodeMines>, mines: Query<&Mine>, index: Res<SpatialIndex>, mut commands: Commands| {
                 // Access resources
                 for entity in index.get_nearby(explode_mines.pos) {
                     // Run queries
@@ -47,10 +44,7 @@ struct Mine {
 impl Mine {
     fn random(rand: &mut ChaCha8Rng) -> Self {
         Mine {
-            pos: Vec2::new(
-                (rand.random::<f32>() - 0.5) * 1200.0,
-                (rand.random::<f32>() - 0.5) * 600.0,
-            ),
+            pos: Vec2::new((rand.random::<f32>() - 0.5) * 1200.0, (rand.random::<f32>() - 0.5) * 600.0),
             size: 4.0 + rand.random::<f32>() * 16.0,
         }
     }
@@ -116,20 +110,14 @@ fn setup(mut commands: Commands) {
 
 fn on_add_mine(add: On<Add, Mine>, query: Query<&Mine>, mut index: ResMut<SpatialIndex>) {
     let mine = query.get(add.entity).unwrap();
-    let tile = (
-        (mine.pos.x / CELL_SIZE).floor() as i32,
-        (mine.pos.y / CELL_SIZE).floor() as i32,
-    );
+    let tile = ((mine.pos.x / CELL_SIZE).floor() as i32, (mine.pos.y / CELL_SIZE).floor() as i32);
     index.map.entry(tile).or_default().insert(add.entity);
 }
 
 // Remove despawned mines from our index
 fn on_remove_mine(remove: On<Remove, Mine>, query: Query<&Mine>, mut index: ResMut<SpatialIndex>) {
     let mine = query.get(remove.entity).unwrap();
-    let tile = (
-        (mine.pos.x / CELL_SIZE).floor() as i32,
-        (mine.pos.y / CELL_SIZE).floor() as i32,
-    );
+    let tile = ((mine.pos.x / CELL_SIZE).floor() as i32, (mine.pos.y / CELL_SIZE).floor() as i32);
     index.map.entry(tile).and_modify(|set| {
         set.remove(&remove.entity);
     });
@@ -153,11 +141,7 @@ fn explode_mine(explode: On<Explode>, query: Query<&Mine>, mut commands: Command
 // Draw a circle for each mine using `Gizmos`
 fn draw_shapes(mut gizmos: Gizmos, mines: Query<&Mine>) {
     for mine in &mines {
-        gizmos.circle_2d(
-            mine.pos,
-            mine.size,
-            Color::hsl((mine.size - 4.0) / 16.0 * 360.0, 1.0, 0.8),
-        );
+        gizmos.circle_2d(mine.pos, mine.size, Color::hsl((mine.size - 4.0) / 16.0 * 360.0, 1.0, 0.8));
     }
 }
 
@@ -194,10 +178,7 @@ const CELL_SIZE: f32 = 64.0;
 impl SpatialIndex {
     // Lookup all entities within adjacent cells of our spatial index
     fn get_nearby(&self, pos: Vec2) -> Vec<Entity> {
-        let tile = (
-            (pos.x / CELL_SIZE).floor() as i32,
-            (pos.y / CELL_SIZE).floor() as i32,
-        );
+        let tile = ((pos.x / CELL_SIZE).floor() as i32, (pos.y / CELL_SIZE).floor() as i32);
         let mut nearby = Vec::new();
         for x in -1..2 {
             for y in -1..2 {
diff --git a/snake-game/examples/paddle_demo.rs b/snake-game/examples/paddle_demo.rs
index 9345eba..3556b8b 100644
--- a/snake-game/examples/paddle_demo.rs
+++ b/snake-game/examples/paddle_demo.rs
@@ -1,4 +1,3 @@
-
 use bevy::math::bounding::{Aabb2d, BoundingCircle, BoundingVolume, IntersectsVolume};
 use bevy::prelude::*;
 
@@ -7,10 +6,7 @@ fn main() {
         .add_plugins(DefaultPlugins)
         .insert_resource(ClearColor(Color::srgb(0.8, 0.8, 1.0)))
         .add_systems(Startup, setup)
-        .add_systems(
-            FixedUpdate,
-            (move_paddle, apply_velocity, check_for_collisions),
-        )
+        .add_systems(FixedUpdate, (move_paddle, apply_velocity, check_for_collisions))
         .run();
 }
 
@@ -40,11 +36,7 @@ struct Ball;
 #[derive(Component)]
 struct Collider;
 
-fn setup(
-    mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
-    mut materials: ResMut<Assets<ColorMaterial>>,
-) {
+fn setup(mut commands: Commands, mut meshes: ResMut<Assets<Mesh>>, mut materials: ResMut<Assets<ColorMaterial>>) {
     commands.spawn(Camera2d);
 
     let paddle_y = BOTTOM_WALL + PADDLE_GAP_Y;
@@ -77,11 +69,7 @@ fn setup(
     commands.spawn(Wall::new(WallLocation::Bottom));
 }
 
-fn move_paddle(
-    input: Res<ButtonInput<KeyCode>>,
-    time: Res<Time>,
-    mut paddle_transform: Single<&mut Transform, With<Paddle>>,
-) {
+fn move_paddle(input: Res<ButtonInput<KeyCode>>, time: Res<Time>, mut paddle_transform: Single<&mut Transform, With<Paddle>>) {
     let direction = if input.pressed(KeyCode::ArrowLeft) {
         -1.0
     } else if input.pressed(KeyCode::ArrowRight) {
@@ -107,19 +95,13 @@ fn apply_velocity(time: Res<Time>, mut query: Query<(&mut Transform, &Velocity)>
     }
 }
 
-fn check_for_collisions(
-    ball_query: Single<(&mut Velocity, &Transform), With<Ball>>,
-    collider_query: Query<&Transform, With<Collider>>,
-) {
+fn check_for_collisions(ball_query: Single<(&mut Velocity, &Transform), With<Ball>>, collider_query: Query<&Transform, With<Collider>>) {
     let (mut ball_velocity, ball_transform) = ball_query.into_inner();
 
     for collider_transform in &collider_query {
         let collision = ball_collision(
             BoundingCircle::new(ball_transform.translation.truncate(), BALL_DIAMETER / 2.0),
-            Aabb2d::new(
-                collider_transform.translation.truncate(),
-                collider_transform.scale.truncate() / 2.0,
-            ),
+            Aabb2d::new(collider_transform.translation.truncate(), collider_transform.scale.truncate() / 2.0),
         );
 
         if let Some(collision) = collision {
@@ -160,11 +142,7 @@ fn ball_collision(circle: BoundingCircle, rect: Aabb2d) -> Option<Collision> {
     let offset = circle.center() - closest;
 
     let side = if offset.x.abs() > offset.y.abs() {
-        if offset.x < 0.0 {
-            Collision::Left
-        } else {
-            Collision::Right
-        }
+        if offset.x < 0.0 { Collision::Left } else { Collision::Right }
     } else if offset.y > 0.0 {
         Collision::Top
     } else {
@@ -212,12 +190,8 @@ impl WallLocation {
 
     fn size(&self) -> Vec2 {
         match self {
-            WallLocation::Left | WallLocation::Right => {
-                Vec2::new(WALL_WIDTH, TOP_WALL - BOTTOM_WALL)
-            }
-            WallLocation::Top | WallLocation::Bottom => {
-                Vec2::new(RIGHT_WALL - LEFT_WALL, WALL_WIDTH)
-            }
+            WallLocation::Left | WallLocation::Right => Vec2::new(WALL_WIDTH, TOP_WALL - BOTTOM_WALL),
+            WallLocation::Top | WallLocation::Bottom => Vec2::new(RIGHT_WALL - LEFT_WALL, WALL_WIDTH),
         }
     }
 }
diff --git a/snake-game/examples/time.rs b/snake-game/examples/time.rs
index c9f21d9..4be23b7 100644
--- a/snake-game/examples/time.rs
+++ b/snake-game/examples/time.rs
@@ -47,21 +47,15 @@ fn runner(mut app: App) -> AppExit {
             }
             "f" => {
                 println!("FAST: setting relative speed to 2x");
-                app.world_mut()
-                    .resource_mut::<Time<Virtual>>()
-                    .set_relative_speed(2.0);
+                app.world_mut().resource_mut::<Time<Virtual>>().set_relative_speed(2.0);
             }
             "n" => {
                 println!("NORMAL: setting relative speed to 1x");
-                app.world_mut()
-                    .resource_mut::<Time<Virtual>>()
-                    .set_relative_speed(1.0);
+                app.world_mut().resource_mut::<Time<Virtual>>().set_relative_speed(1.0);
             }
             "s" => {
                 println!("SLOW: setting relative speed to 0.5x");
-                app.world_mut()
-                    .resource_mut::<Time<Virtual>>()
-                    .set_relative_speed(0.5);
+                app.world_mut().resource_mut::<Time<Virtual>>().set_relative_speed(0.5);
             }
             "p" => {
                 println!("PAUSE: pausing virtual clock");
diff --git a/snake-game/rustfmt.toml b/snake-game/rustfmt.toml
new file mode 100644
index 0000000..ac173ef
--- /dev/null
+++ b/snake-game/rustfmt.toml
@@ -0,0 +1,3 @@
+max_width = 160
+newline_style = "Unix"
+fn_single_line = true
diff --git a/snake-game/src/debug.rs b/snake-game/src/debug.rs
index a70919b..8729a29 100644
--- a/snake-game/src/debug.rs
+++ b/snake-game/src/debug.rs
@@ -8,11 +8,7 @@ pub fn print_all_entities(mut commands: Commands, query: Query<Entity>) {
 }
 
 /// ДЛЯ ОТЛАДКИ - вывод всех сущностей мира по нажатию Enter
-pub fn print_all_entities_by_press_enter(
-    input: Res<ButtonInput<KeyCode>>,
-    mut commands: Commands,
-    query: Query<Entity>,
-) {
+pub fn print_all_entities_by_press_enter(input: Res<ButtonInput<KeyCode>>, mut commands: Commands, query: Query<Entity>) {
     if input.just_pressed(KeyCode::Enter) {
         for entity in query {
             commands.entity(entity).log_components();
@@ -28,9 +24,7 @@ pub struct Grid;
 pub fn spawn_grid(commands: &mut Commands) {
     use crate::domain::GRID_SIZE;
 
-    let grid = commands
-        .spawn((Grid, Transform::default(), Visibility::default()))
-        .id();
+    let grid = commands.spawn((Grid, Transform::default(), Visibility::default())).id();
 
     for x in -20..=20 {
         commands.spawn((
diff --git a/snake-game/src/domain.rs b/snake-game/src/domain.rs
index 3f8da36..2ba6f8b 100644
--- a/snake-game/src/domain.rs
+++ b/snake-game/src/domain.rs
@@ -1,7 +1,9 @@
-use std::collections::HashMap;
+use std::{collections::HashMap, fmt::Debug};
 
 use bevy::prelude::*;
 
+use crate::tools::Position;
+
 pub const GRID_SIZE: u8 = 48;
 pub const HEAD_SIZE: u8 = (GRID_SIZE as f32 * 1.1) as u8;
 pub const SNAKE_VELOCITY: u8 = (GRID_SIZE as f32 / 1.0) as u8;
@@ -20,7 +22,19 @@ pub struct End;
 
 /// Событие прохождения границы сетки
 #[derive(EntityEvent)]
-pub struct GridBarier(pub Entity);
+pub struct GridBarier {
+    pub entity: Entity,
+    #[allow(unused)]
+    pub src_pos: Position,
+    #[allow(unused)]
+    pub dst_pos: Position,
+}
+
+impl GridBarier {
+    pub fn new(entity: Entity, src_pos: Position, dst_pos: Position) -> Self {
+        Self { entity, src_pos, dst_pos }
+    }
+}
 
 /// Направление движения
 #[derive(Component, PartialEq, Clone, Copy, Debug)]
@@ -93,30 +107,27 @@ pub struct Inert(pub Direction);
 
 /// Путь змеи
 #[derive(Resource, Default, Debug)]
-pub struct SnakePath(HashMap<(i16, i16), Direction>);
+pub struct SnakePath(HashMap<Position, Direction>);
 
 impl SnakePath {
-    fn to_key(transform: &Transform) -> (i16, i16) {
-        (
-            (transform.translation.x / GRID_SIZE as f32).floor() as i16,
-            (transform.translation.y / GRID_SIZE as f32).floor() as i16,
-        )
-    }
-
-    pub fn push(&mut self, transform: &Transform, direction: Direction) -> (i16, i16, Direction) {
-        let key = SnakePath::to_key(transform);
+    pub fn push(&mut self, transform: &Transform, direction: Direction) -> (Position, Direction) {
+        let key = transform.into();
         self.0.insert(key, direction.clone());
-        (key.0, key.1, direction.clone())
+        (key, direction.clone())
     }
 
-    pub fn pick(&self, transform: &Transform) -> Option<(i16, i16, Direction)> {
-        let key = SnakePath::to_key(transform);
-        self.0.get(&key).cloned().map(|d| (key.0, key.1, d))
+    pub fn pick(&self, transform: &Transform) -> Option<(Position, Direction)> {
+        let key = transform.into();
+        self.0.get(&key).cloned().map(|d| (key, d))
     }
 
-    pub fn drop(&mut self, transform: &Transform) -> Option<(i16, i16, Direction)> {
-        let key = SnakePath::to_key(transform);
-        self.0.remove(&key).map(|d| (key.0, key.1, d))
+    pub fn drop(&mut self, transform: &Transform) -> Option<(Position, Direction)> {
+        let key = transform.into();
+        self.0.remove(&key).map(|d| (key, d))
+    }
+
+    pub fn debug(&self) -> impl Debug {
+        &self.0
     }
 }
 
@@ -132,10 +143,10 @@ mod test {
         snake_path.push(&Transform::default(), Direction::default());
         assert_eq!(snake_path.0.len(), 1);
 
-        assert!(snake_path.pick(&Transform::default()) == Some((0, 0, Direction::default())));
+        assert!(snake_path.pick(&Transform::default()) == Some((Position::default(), Direction::default())));
         assert_eq!(snake_path.0.len(), 1);
 
-        assert!(snake_path.drop(&Transform::default()) == Some((0, 0, Direction::default())));
+        assert!(snake_path.drop(&Transform::default()) == Some((Position::default(), Direction::default())));
         assert_eq!(snake_path.0.len(), 0);
     }
 }
diff --git a/snake-game/src/gameplay.rs b/snake-game/src/gameplay.rs
index efd27e7..cb11299 100644
--- a/snake-game/src/gameplay.rs
+++ b/snake-game/src/gameplay.rs
@@ -6,11 +6,7 @@ use crate::{
 };
 
 /// Система поворота головы змеи
-pub fn head_rotation(
-    input: Res<ButtonInput<KeyCode>>,
-    query: Single<(&mut Transform, &mut Direction), With<Head>>,
-    mut snake_path: ResMut<SnakePath>,
-) {
+pub fn head_rotation(input: Res<ButtonInput<KeyCode>>, query: Single<(&mut Transform, &mut Direction), With<Head>>, mut snake_path: ResMut<SnakePath>) {
     use core::f32::consts::PI;
 
     let (mut transform, mut direction) = query.into_inner();
@@ -33,17 +29,14 @@ pub fn head_rotation(
 }
 
 /// Система движения для всех движущихся сущностей
-pub fn moving(
-    time: Res<Time<Fixed>>,
-    query: Query<(&mut Transform, &mut Inert, &Direction, &Velocity, Entity)>,
-    mut commands: Commands,
-) {
+pub fn moving(time: Res<Time<Fixed>>, query: Query<(&mut Transform, &mut Inert, &Direction, &Velocity, Entity)>, mut commands: Commands) {
     for (mut transform, mut inert, direction, Velocity(velocity), entity) in query.into_iter() {
+        let src_transftorm = transform.clone();
         let delta = velocity * time.delta_secs();
         let src = inert.0.get_coord(&transform);
         let sign = inert.0.get_change_sign();
         let dst = src + sign * delta;
-        let mut splited = _split_by_grid_tracing(src, dst, GRID_SIZE as f32).into_iter();
+        let mut splited = split_by_grid(src, dst, GRID_SIZE as f32).into_iter();
         let first = splited.next().unwrap_or((0.0, 0.0));
         inert.0.set_coord(&mut transform, first.0);
         if let Some(second) = splited.next() {
@@ -53,16 +46,13 @@ pub fn moving(
             let sign = inert.0.get_change_sign();
             let dst = src + sign * delta;
             inert.0.set_coord(&mut transform, dst);
-            commands.trigger(GridBarier(entity));
+            commands.trigger(GridBarier::new(entity, (&src_transftorm).into(), transform.into()));
         }
     }
 }
 
 fn _split_by_grid_tracing(src: f32, dst: f32, grid: f32) -> Vec<(f32, f32)> {
     let result = split_by_grid(src, dst, grid);
-    trace!(
-        "\tsplit_by_grid({:?}, {:?}, {:?}) -> {:?}",
-        src, dst, grid, result
-    );
+    trace!("\tsplit_by_grid({:?}, {:?}, {:?}) -> {:?}", src, dst, grid, result);
     result
 }
diff --git a/snake-game/src/observers.rs b/snake-game/src/observers.rs
index d6b7a8a..1c9e33a 100644
--- a/snake-game/src/observers.rs
+++ b/snake-game/src/observers.rs
@@ -4,18 +4,12 @@ use bevy::prelude::*;
 
 #[allow(unused)]
 /// Слушатель событий [GridBarier] для хвоста, обновляющий направление его движения из ресурса [SnakePath] и позволяющий следовать за головой
-pub fn tail_observer(
-    event: On<GridBarier>,
-    mut query: Query<(&mut Direction, &Transform)>,
-    snake_path: Res<SnakePath>,
-) {
-    if event.observer() == event.0 {
-        if let Ok((mut direction, transform)) = query.get_mut(event.0) {
-            if let Some((x, y, new_direction)) = snake_path.pick(transform) {
-                trace!(
-                    "change direction for {:?} in ({:?}, {:?}) to {:?}",
-                    event.0, x, y, new_direction
-                );
+pub fn tail_observer(event: On<GridBarier>, mut query: Query<(&mut Direction, &Transform)>, snake_path: Res<SnakePath>) {
+    let entity = event.entity;
+    if event.observer() == entity {
+        if let Ok((mut direction, transform)) = query.get_mut(event.entity) {
+            if let Some((position, new_direction)) = snake_path.pick(transform) {
+                trace!("change direction for {entity:?} in {position:?} to {new_direction:?}");
                 *direction = new_direction;
             }
         }
@@ -23,33 +17,28 @@ pub fn tail_observer(
 }
 
 /// Слушатель событий [GridBarier] для конца змеи, обновляющий направление его движения из ресурса [SnakePath] и удаляющий полученные значения из [SnakePath]
-pub fn cleanup_snake_path(
-    event: On<GridBarier>,
-    mut commands: Commands,
-    query: Query<&Transform, With<End>>,
-) {
-    if let Ok(transform) = query.get(event.0) {
+pub fn cleanup_snake_path(event: On<GridBarier>, mut commands: Commands, query: Query<&Transform, With<End>>) {
+    if let Ok(transform) = query.get(event.entity) {
         // trace!("schedule cleaning SnakePath for {:?}", transform);
         let transform = transform.clone();
         commands.queue(move |world: &mut World| {
             let mut snake_path = world.resource_mut::<SnakePath>();
-            if let Some((x, y, dir)) = snake_path.drop(&transform) {
-                trace!(
-                    "removed entry from SnakePath: ({:?}, {:?}) => {:?}\n\tsnake_path: {:?}",
-                    x, y, dir, *snake_path
-                );
+            if let Some((pos, dir)) = snake_path.drop(&transform) {
+                let map = snake_path.debug();
+                trace!("removed entry from SnakePath: {pos:?} => {dir:?}\n\tsnake_path: {map:?}");
             }
         });
     }
 }
 
 /// Запланировать установку скорости движения [Velocity] при следующем событии [GridBarier]
-pub fn schedule_set_velocity(tail: Entity) -> impl Fn(On<GridBarier>, Commands) {
-    move |event: On<GridBarier>, mut commands: Commands| {
-        commands
-            .entity(tail)
-            .entry::<Velocity>()
-            .and_modify(|mut velocity| velocity.0 = SNAKE_VELOCITY as f32);
-        commands.entity(event.observer()).despawn();
+pub fn schedule_set_velocity(tail: Entity) -> impl Fn(On<GridBarier>, Commands, Query<(&mut Velocity, &Transform)>) {
+    move |event: On<GridBarier>, mut commands: Commands, mut query: Query<(&mut Velocity, &Transform)>| {
+        if let Ok((mut velocity, transform)) = query.get_mut(tail) {
+            if event.dst_pos != transform.into() {
+                velocity.0 = SNAKE_VELOCITY as f32;
+                commands.entity(event.observer()).despawn();
+            }
+        }
     }
 }
diff --git a/snake-game/src/startup.rs b/snake-game/src/startup.rs
index 2600c73..5c9bba0 100644
--- a/snake-game/src/startup.rs
+++ b/snake-game/src/startup.rs
@@ -1,7 +1,7 @@
 use bevy::prelude::*;
 
 use crate::{
-    domain::{End, SnakePath, Tail},
+    domain::{End, GridBarier, SnakePath, Tail},
     observers::{cleanup_snake_path, schedule_set_velocity, tail_observer},
 };
 
@@ -20,16 +20,20 @@ fn spawn_snake(commands: &mut Commands) {
     commands.insert_resource(SnakePath::default());
     commands.spawn(Observer::new(cleanup_snake_path));
 
+    commands.spawn(Observer::new(|e: On<GridBarier>| {
+        let entity = e.entity;
+        let src = e.src_pos;
+        let dst = e.dst_pos;
+        trace!("...<{entity:?}> moving {src:>16} => {dst:>16}");
+    }));
+
     let head = commands
         .spawn((
             Head,
             Direction::default(),
             Inert::default(),
             Velocity(SNAKE_VELOCITY as f32),
-            Sprite::from_color(
-                Color::srgb(1., 1., 1.),
-                vec2(HEAD_SIZE as f32, HEAD_SIZE as f32),
-            ),
+            Sprite::from_color(Color::srgb(1., 1., 1.), vec2(HEAD_SIZE as f32, HEAD_SIZE as f32)),
             Transform {
                 translation: vec3(0.0, 0.0, 1.0),
                 ..Default::default()
@@ -37,10 +41,7 @@ fn spawn_snake(commands: &mut Commands) {
         ))
         .id();
     commands.spawn((
-        Sprite::from_color(
-            Color::srgb(1., 0., 0.),
-            vec2(HEAD_SIZE as f32 * 0.3, HEAD_SIZE as f32 * 0.3),
-        ),
+        Sprite::from_color(Color::srgb(1., 0., 0.), vec2(HEAD_SIZE as f32 * 0.3, HEAD_SIZE as f32 * 0.3)),
         Transform {
             translation: vec3(HEAD_SIZE as f32 * -0.25, HEAD_SIZE as f32 * 0.25, 1.0),
             ..Default::default()
@@ -48,10 +49,7 @@ fn spawn_snake(commands: &mut Commands) {
         ChildOf(head),
     ));
     commands.spawn((
-        Sprite::from_color(
-            Color::srgb(0., 0., 1.),
-            vec2(HEAD_SIZE as f32 * 0.2, HEAD_SIZE as f32 * 0.2),
-        ),
+        Sprite::from_color(Color::srgb(0., 0., 1.), vec2(HEAD_SIZE as f32 * 0.2, HEAD_SIZE as f32 * 0.2)),
         Transform {
             translation: vec3(HEAD_SIZE as f32 * 0.25, HEAD_SIZE as f32 * 0.25, 1.0),
             ..Default::default()
@@ -66,10 +64,7 @@ fn spawn_snake(commands: &mut Commands) {
             Direction::default(),
             Inert::default(),
             Velocity(0.0),
-            Sprite::from_color(
-                Color::srgb(0.7, 0.7, 0.7),
-                vec2(HEAD_SIZE as f32 * 0.8, HEAD_SIZE as f32 * 0.8),
-            ),
+            Sprite::from_color(Color::srgb(0.7, 0.7, 0.7), vec2(HEAD_SIZE as f32 * 0.8, HEAD_SIZE as f32 * 0.8)),
             Transform {
                 translation: vec3(0.0, 0.0, 0.0),
                 ..Default::default()
diff --git a/snake-game/src/tools.rs b/snake-game/src/tools.rs
index baf600d..8e9a4f0 100644
--- a/snake-game/src/tools.rs
+++ b/snake-game/src/tools.rs
@@ -13,12 +13,7 @@ pub fn define_log_layer() -> Option<bevy::log::BoxedFmtLayer> {
         .with_line_number(false)
         .with_filter(targets.clone())
         .boxed();
-    let file = match File::options()
-        .write(true)
-        .create(true)
-        .append(true)
-        .open("snake-game.log")
-    {
+    let file = match File::options().write(true).create(true).append(true).open("snake-game.log") {
         Ok(file) => file,
         Err(e) => {
             eprintln!("No access to log file: {:?}", e);
@@ -54,9 +49,9 @@ pub fn split_by_grid(src: f32, dst: f32, grid: f32) -> Vec<(f32, f32)> {
         let mut src: f32 = src;
         for step in old_grid_right as i32..new_grid_right as i32 {
             let step = step as f32 * grid;
-            if step != src {
-                output.push((step, step - src));
-            }
+            // if step != src {
+            output.push((step, step - src));
+            // }
             src = step;
         }
         output.push((dst, dst - src));
@@ -64,9 +59,9 @@ pub fn split_by_grid(src: f32, dst: f32, grid: f32) -> Vec<(f32, f32)> {
         let mut dst: f32 = dst;
         for step in new_grid_right as i32..old_grid_right as i32 {
             let step = step as f32 * grid;
-            if step != dst {
-                output.push((dst, dst - step));
-            }
+            // if step != dst {
+            output.push((dst, dst - step));
+            // }
             dst = step;
         }
         output.push((dst, dst - src));
@@ -86,53 +81,32 @@ mod test {
         assert_eq!(split_by_grid(3.0, 5.0, 5.0), vec![(5.0, 2.0)]);
         assert_eq!(split_by_grid(3.0, 6.0, 5.0), vec![(5.0, 2.0), (6.0, 1.0)]);
         assert_eq!(split_by_grid(3.0, 10.0, 5.0), vec![(5.0, 2.0), (10.0, 5.0)]);
-        assert_eq!(
-            split_by_grid(3.0, 11.0, 5.0),
-            vec![(5.0, 2.0), (10.0, 5.0), (11.0, 1.0)]
-        );
+        assert_eq!(split_by_grid(3.0, 11.0, 5.0), vec![(5.0, 2.0), (10.0, 5.0), (11.0, 1.0)]);
         assert_eq!(split_by_grid(-2.0, 3.0, 5.0), vec![(0.0, 2.0), (3.0, 3.0)]);
-        assert_eq!(
-            split_by_grid(-6.0, 7.0, 5.0),
-            vec![(-5.0, 1.0), (0.0, 5.0), (5.0, 5.0), (7.0, 2.0)]
-        );
-        assert_eq!(
-            split_by_grid(-6.0, -2.0, 5.0),
-            vec![(-5.0, 1.0), (-2.0, 3.0)]
-        );
+        assert_eq!(split_by_grid(-6.0, 7.0, 5.0), vec![(-5.0, 1.0), (0.0, 5.0), (5.0, 5.0), (7.0, 2.0)]);
+        assert_eq!(split_by_grid(-6.0, -2.0, 5.0), vec![(-5.0, 1.0), (-2.0, 3.0)]);
 
         // движение влево
         assert_eq!(split_by_grid(4.0, 1.0, 5.0), vec![(1.0, -3.0)]);
         assert_eq!(split_by_grid(5.0, 3.0, 5.0), vec![(3.0, -2.0)]);
         assert_eq!(split_by_grid(6.0, 3.0, 5.0), vec![(5.0, -1.0), (3.0, -2.0)]);
-        assert_eq!(
-            split_by_grid(10.0, 3.0, 5.0),
-            vec![(5.0, -5.0), (3.0, -2.0)]
-        );
-        assert_eq!(
-            split_by_grid(11.0, 3.0, 5.0),
-            vec![(10.0, -1.0), (5.0, -5.0), (3.0, -2.0)]
-        );
-        assert_eq!(
-            split_by_grid(3.0, -2.0, 5.0),
-            vec![(0.0, -3.0), (-2.0, -2.0)]
-        );
-        assert_eq!(
-            split_by_grid(7.0, -6.0, 5.0),
-            vec![(5.0, -2.0), (0.0, -5.0), (-5.0, -5.0), (-6.0, -1.0)]
-        );
-        assert_eq!(
-            split_by_grid(-2.0, -6.0, 5.0),
-            vec![(-5.0, -3.0), (-6.0, -1.0)]
-        );
+        assert_eq!(split_by_grid(10.0, 3.0, 5.0), vec![(5.0, -5.0), (3.0, -2.0)]);
+        assert_eq!(split_by_grid(11.0, 3.0, 5.0), vec![(10.0, -1.0), (5.0, -5.0), (3.0, -2.0)]);
+        assert_eq!(split_by_grid(3.0, -2.0, 5.0), vec![(0.0, -3.0), (-2.0, -2.0)]);
+        assert_eq!(split_by_grid(7.0, -6.0, 5.0), vec![(5.0, -2.0), (0.0, -5.0), (-5.0, -5.0), (-6.0, -1.0)]);
+        assert_eq!(split_by_grid(-2.0, -6.0, 5.0), vec![(-5.0, -3.0), (-6.0, -1.0)]);
 
         // сценарии с нулевой сеткой
         assert_eq!(split_by_grid(1.0, 4.0, 0.0), vec![(4.0, 3.0)]);
         assert_eq!(split_by_grid(4.0, 1.0, 0.0), vec![(1.0, -3.0)]);
 
         // Сценарии со стартом в узле сетки
-        assert_eq!(split_by_grid(0.0, 1.5, 5.0), vec![(1.5, 1.5)]);
-        assert_eq!(split_by_grid(5.0, 7.0, 5.0), vec![(7.0, 2.0)]);
-        assert_eq!(split_by_grid(0.0, -1.5, 5.0), vec![(-1.5, -1.5)]);
-        assert_eq!(split_by_grid(5.0, 3.0, 5.0), vec![(3.0, -2.0)]);
+        assert_eq!(split_by_grid(0.0, 1.5, 5.0), vec![(0.0, 0.0), (1.5, 1.5)]);
+        assert_eq!(split_by_grid(5.0, 7.0, 5.0), vec![(5.0, 0.0), (7.0, 2.0)]);
+        assert_eq!(split_by_grid(0.0, -1.5, 5.0), vec![(0.0, 0.0), (-1.5, -1.5)]);
+        assert_eq!(split_by_grid(5.0, 3.0, 5.0), vec![(5.0, 0.0), (3.0, -2.0)]);
     }
 }
+
+mod position;
+pub use position::Position;
diff --git a/snake-game/src/tools/position.rs b/snake-game/src/tools/position.rs
new file mode 100644
index 0000000..7072836
--- /dev/null
+++ b/snake-game/src/tools/position.rs
@@ -0,0 +1,32 @@
+use std::{fmt::Display, ops::Deref};
+
+use bevy::transform::components::Transform;
+
+use crate::domain::GRID_SIZE;
+
+#[derive(Clone, Copy, Default, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Position {
+    pub x: i8,
+    pub y: i8,
+}
+
+impl Position {
+    pub fn new(x: i8, y: i8) -> Self {
+        Self { x, y }
+    }
+}
+
+impl Display for Position {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "(x:{}, y:{})", self.x, self.y)
+    }
+}
+
+impl<T: Deref<Target = Transform>> From<T> for Position {
+    fn from(value: T) -> Self {
+        Self {
+            x: (value.translation.x / GRID_SIZE as f32) as i8,
+            y: (value.translation.y / GRID_SIZE as f32) as i8,
+        }
+    }
+}