feat: Implement Pom and Pom movement (#16, #20)

src/components/pom.rs

@@ -1,4 +1,39 @@
+use std::collections::VecDeque;
+
 use bevy::prelude::*;
 
 #[derive(Component)]
 pub struct Pom;
+
+#[derive(Component)]
+pub struct GridPosition {
+    pub x: u32,
+    pub y: u32,
+}
+
+#[derive(Component, Default)]
+pub struct PathQueue {
+    pub steps: VecDeque<(u32, u32)>,
+}
+
+#[derive(Component, Default)]
+pub enum MovingState {
+    #[default]
+    Idle,
+    MovingUp,
+    MovingDown,
+    MovingLeft,
+    MovingRight,
+}
+
+impl MovingState {
+    pub fn is_moving(&self) -> bool {
+        matches!(
+            self,
+            MovingState::MovingUp
+                | MovingState::MovingDown
+                | MovingState::MovingLeft
+                | MovingState::MovingRight
+        )
+    }
+}

src/components/tile.rs

@@ -1,5 +1,6 @@
 use bevy::prelude::*;
-use bevy_aseprite_ultra::prelude::AseSlice;
+
+use crate::errors::GridError;
 
 #[derive(Component)]
 pub struct Tile {
@@ -15,9 +16,49 @@ pub enum TileState {
     Occupied,
 }
 
+impl TileState {
+    pub fn is_blocking(&self) -> bool {
+        match self {
+            TileState::Occupied => true,
+            _ => false,
+        }
+    }
+}
+
 #[derive(Resource)]
 pub struct Grid {
     pub width: u32,
     pub height: u32,
     pub tiles: Vec<Vec<Entity>>,
 }
+
+impl Grid {
+    pub fn get_tile(&self, pos: (u32, u32)) -> Result<Entity, GridError> {
+        if pos.0 >= self.width || pos.1 >= self.height {
+            return Err(GridError::OutOfBounds {
+                x: pos.0 as i32,
+                y: pos.1 as i32,
+            });
+        }
+        Ok(self.tiles[pos.0 as usize][pos.1 as usize])
+    }
+
+    pub fn map_tile_state<F>(
+        &self,
+        pos: (u32, u32),
+        mapper: F,
+        mut tile_query: Query<&mut TileState>,
+    ) -> Result<(), GridError>
+    where
+        F: FnOnce(&TileState) -> TileState,
+    {
+        let tile_entity = self.get_tile(pos)?;
+
+        let mut tile_state = tile_query
+            .get_mut(tile_entity)
+            .map_err(|_| GridError::UnknownError)?;
+
+        *tile_state = mapper(&*tile_state);
+        Ok(())
+    }
+}

src/errors.rs

@@ -0,0 +1,15 @@
+use std::{error::Error, fmt};
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum GridError {
+    OutOfBounds { x: i32, y: i32 },
+    UnknownError,
+}
+
+impl Error for GridError {}
+
+impl fmt::Display for GridError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "GridError: {}", &self.to_string())
+    }
+}

src/lib.rs

@@ -1,3 +1,6 @@
 pub mod components;
+pub mod errors;
+pub mod messages;
 pub mod plugins;
 pub mod states;
+pub mod utils;

src/main.rs

@@ -26,6 +26,8 @@ fn main() {
             plugins::StartScreenPlugin,
             plugins::GameScreenPlugin,
             plugins::GridPlugin,
+            plugins::PomPlugin,
+            plugins::InputPlugin,
         ))
         .run();
 }

src/messages.rs

@@ -0,0 +1,18 @@
+use bevy::prelude::*;
+
+#[derive(Message)]
+pub struct MoveMessage {
+    pub x: u32,
+    pub y: u32,
+}
+
+#[derive(Message)]
+pub struct InvalidMoveMessage {
+    pub message: String,
+}
+
+#[derive(Message)]
+pub struct InteractStartMessage {
+    pub x: u32,
+    pub y: u32,
+}

src/plugins/game_screen.rs

@@ -1,7 +1,5 @@
-use crate::components::*;
 use crate::states::*;
 use bevy::prelude::*;
-use bevy_aseprite_ultra::prelude::*;
 
 pub struct GameScreenPlugin;
 
@@ -12,17 +10,7 @@ impl Plugin for GameScreenPlugin {
     }
 }
 
-fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
-    commands.spawn((
-        pom::Pom,
-        AseAnimation {
-            aseprite: asset_server.load("pom/pom-sleep.aseprite"),
-            animation: Animation::tag("sleep-sit-start").with_repeat(AnimationRepeat::Loop),
-        },
-        Sprite::default(),
-        Transform::from_xyz(0.0, 0.0, 1.0),
-    ));
-
+fn setup(mut commands: Commands) {
     commands.insert_resource(ClearColor(Color::srgb(0.294, 0.412, 0.184)));
 }
 

src/plugins/grid.rs

@@ -5,12 +5,12 @@ use crate::{
 use bevy::prelude::*;
 use bevy_aseprite_ultra::prelude::AseSlice;
 
-const TILE_SIZE: f32 = 32.0;
-const GRID_WIDTH: u32 = 10;
-const GRID_HEIGHT: u32 = 10;
+pub const TILE_SIZE: f32 = 32.0;
+pub const GRID_WIDTH: u32 = 10;
+pub const GRID_HEIGHT: u32 = 10;
 
-const GRID_START_X: f32 = -(GRID_WIDTH as f32 * TILE_SIZE) / 2.0 + TILE_SIZE / 2.0;
-const GRID_START_Y: f32 = -(GRID_HEIGHT as f32 * TILE_SIZE) / 2.0 + TILE_SIZE / 2.0;
+pub const GRID_START_X: f32 = -(GRID_WIDTH as f32 * TILE_SIZE) / 2.0 + TILE_SIZE / 2.0;
+pub const GRID_START_Y: f32 = -(GRID_HEIGHT as f32 * TILE_SIZE) / 2.0 + TILE_SIZE / 2.0;
 
 pub struct GridPlugin;
 
@@ -42,11 +42,7 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
                         aseprite: asset_server.load("tiles/tile-unclaimed.aseprite"),
                     },
                     Sprite::default(),
-                    Transform::from_xyz(
-                        GRID_START_X + x as f32 * TILE_SIZE,
-                        GRID_START_Y + y as f32 * TILE_SIZE,
-                        0.0,
-                    ),
+                    Transform::from_translation(grid_to_world_coords(x, y, None)),
                 ))
                 .id();
             column.push(tile_entity);
@@ -87,3 +83,28 @@ fn update_tile_colors(
         };
     }
 }
+
+pub fn world_to_grid_coords(world_pos: Vec3) -> (u32, u32) {
+    let x = ((world_pos.x - GRID_START_X + TILE_SIZE / 2.0) / TILE_SIZE).floor();
+    let y = ((world_pos.y - GRID_START_Y + TILE_SIZE / 2.0) / TILE_SIZE).floor();
+
+    let mut x_u32 = x as u32;
+    let mut y_u32 = y as u32;
+
+    if x_u32 >= GRID_WIDTH {
+        x_u32 = GRID_WIDTH - 1;
+    }
+    if y_u32 >= GRID_HEIGHT {
+        y_u32 = GRID_HEIGHT - 1;
+    }
+
+    (x_u32, y_u32)
+}
+
+pub fn grid_to_world_coords(grid_x: u32, grid_y: u32, z: Option<f32>) -> Vec3 {
+    Vec3::new(
+        GRID_START_X + grid_x as f32 * TILE_SIZE,
+        GRID_START_Y + grid_y as f32 * TILE_SIZE,
+        z.unwrap_or(0.0),
+    )
+}

src/plugins/input.rs

@@ -0,0 +1,84 @@
+use bevy::input::mouse::MouseButton;
+use bevy::prelude::*;
+use bevy::window::PrimaryWindow;
+
+use crate::components::tile::{Grid, TileState};
+use crate::messages::{InteractStartMessage, InvalidMoveMessage, MoveMessage};
+use crate::plugins::grid::world_to_grid_coords;
+use crate::states::AppState;
+
+pub struct InputPlugin;
+
+impl Plugin for InputPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_message::<MoveMessage>();
+        app.add_message::<InvalidMoveMessage>();
+        app.add_systems(Update, move_click.run_if(in_state(AppState::GameScreen)));
+
+        app.add_message::<InteractStartMessage>();
+        app.add_systems(
+            Update,
+            interact_click.run_if(in_state(AppState::GameScreen)),
+        );
+    }
+}
+
+fn move_click(
+    mut move_messages: MessageWriter<MoveMessage>,
+    mouse_btn: Res<ButtonInput<MouseButton>>,
+    window: Single<&Window, With<PrimaryWindow>>,
+    camera: Single<(&Camera, &GlobalTransform), With<Camera2d>>,
+) {
+    if mouse_btn.just_pressed(MouseButton::Right) {
+        let (cam, cam_transform) = *camera;
+
+        let Some(cursor_pos) = window.cursor_position() else {
+            return;
+        };
+        let Ok(world_pos) = cam.viewport_to_world(cam_transform, cursor_pos) else {
+            return;
+        };
+        let (x, y) = world_to_grid_coords(world_pos.origin);
+
+        println!("Move Click: ({}, {})", x, y);
+        move_messages.write(MoveMessage { x, y });
+    }
+}
+
+fn interact_click(
+    mut interact_messages: MessageWriter<InteractStartMessage>,
+    mouse_btn: Res<ButtonInput<MouseButton>>,
+    window: Single<&Window, With<PrimaryWindow>>,
+    camera: Single<(&Camera, &GlobalTransform), With<Camera2d>>,
+    // for debug
+    grid: ResMut<Grid>,
+    tile_query: Query<&mut TileState>,
+) {
+    if mouse_btn.just_pressed(MouseButton::Left) {
+        let (cam, cam_transform) = *camera;
+
+        let Some(cursor_pos) = window.cursor_position() else {
+            return;
+        };
+        let Ok(world_pos) = cam.viewport_to_world(cam_transform, cursor_pos) else {
+            return;
+        };
+        let (x, y) = world_to_grid_coords(world_pos.origin);
+
+        println!("Interact Click: ({}, {})", x, y);
+        interact_messages.write(InteractStartMessage { x, y });
+
+        if cfg!(debug_assertions) {
+            grid.map_tile_state(
+                (x, y),
+                |state| match state {
+                    TileState::Unclaimed => TileState::Empty,
+                    TileState::Empty => TileState::Occupied,
+                    TileState::Occupied => TileState::Unclaimed,
+                },
+                tile_query,
+            )
+            .unwrap();
+        }
+    }
+}

src/plugins/mod.rs

@@ -1,9 +1,13 @@
 pub mod core;
 pub mod game_screen;
 pub mod grid;
+pub mod input;
+pub mod pom;
 pub mod start_screen;
 
 pub use core::CorePlugin;
 pub use game_screen::GameScreenPlugin;
 pub use grid::GridPlugin;
+pub use input::InputPlugin;
+pub use pom::PomPlugin;
 pub use start_screen::StartScreenPlugin;

src/plugins/pom.rs

@@ -0,0 +1,145 @@
+use crate::components::pom::{GridPosition, MovingState, PathQueue, Pom};
+use crate::components::tile::{Grid, TileState};
+use crate::messages::{InvalidMoveMessage, MoveMessage};
+use crate::plugins::grid::{GRID_WIDTH, grid_to_world_coords};
+use crate::states::*;
+use crate::utils::pathfinding::find_path;
+use bevy::prelude::*;
+use bevy_aseprite_ultra::prelude::*;
+
+const MOVE_SPEED: f32 = 2.0 * GRID_WIDTH as f32;
+
+pub struct PomPlugin;
+
+impl Plugin for PomPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(OnEnter(AppState::GameScreen), setup);
+        app.add_systems(OnExit(AppState::GameScreen), cleanup);
+
+        app.add_systems(
+            Update,
+            (handle_move, move_pom, update_pom).run_if(in_state(AppState::GameScreen)),
+        );
+    }
+}
+
+fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
+    commands.spawn((
+        Pom,
+        GridPosition { x: 0, y: 0 },
+        PathQueue::default(),
+        MovingState::default(),
+        AseAnimation {
+            aseprite: asset_server.load("pom/pom-sleep.aseprite"),
+            animation: Animation::tag("sleep-sit-start").with_repeat(AnimationRepeat::Loop),
+        },
+        Sprite::default(),
+        Transform::from_translation(grid_to_world_coords(0, 0, Some(1.0))),
+    ));
+}
+
+fn cleanup(mut commands: Commands, pom_query: Query<Entity, With<Pom>>) {
+    for pom_entity in pom_query.iter() {
+        commands.entity(pom_entity).despawn();
+    }
+}
+
+fn handle_move(
+    mut move_messages: MessageReader<MoveMessage>,
+    mut invalid_move_messages: MessageWriter<InvalidMoveMessage>,
+    grid: Res<Grid>,
+    tile_query: Query<&TileState>,
+    mut pom_query: Query<(&GridPosition, &mut PathQueue)>,
+) {
+    for message in move_messages.read() {
+        for (grid_pos, mut path_queue) in pom_query.iter_mut() {
+            let start = (grid_pos.x, grid_pos.y);
+            let end = (message.x, message.y);
+
+            println!("{}, {}", end.0, end.1);
+
+            match find_path(start, end, &grid, &tile_query) {
+                Some(new_path) => {
+                    path_queue.steps = new_path;
+                    println!("Path found with {} steps", path_queue.steps.len());
+                }
+                None => {
+                    let msg = format!(
+                        "Cannot move to ({}, {}). Path blocked or invalid.",
+                        message.x, message.y
+                    );
+                    println!("{}", msg);
+                    invalid_move_messages.write(InvalidMoveMessage { message: msg });
+                }
+            }
+        }
+    }
+}
+
+fn move_pom(
+    time: Res<Time>,
+    mut query: Query<(
+        &mut Transform,
+        &mut GridPosition,
+        &mut PathQueue,
+        &mut MovingState,
+    )>,
+) {
+    let dt = time.delta_secs();
+
+    for (mut transform, mut grid_pos, mut path_queue, mut moving_state) in query.iter_mut() {
+        if let Some(&target) = path_queue.steps.front() {
+            let target_pos = grid_to_world_coords(target.0, target.1, Some(1.0));
+            let distance = transform.translation.distance(target_pos);
+
+            let dx = target.0 as i32 - grid_pos.x as i32;
+            let dy = target.1 as i32 - grid_pos.y as i32;
+            match (dx, dy) {
+                (0, 1) => *moving_state = MovingState::MovingUp,
+                (0, -1) => *moving_state = MovingState::MovingDown,
+                (1, 0) => *moving_state = MovingState::MovingRight,
+                (-1, 0) => *moving_state = MovingState::MovingLeft,
+                _ => (),
+            }
+
+            if distance < MOVE_SPEED * dt {
+                transform.translation = target_pos;
+                grid_pos.x = target.0;
+                grid_pos.y = target.1;
+                path_queue.steps.pop_front();
+            } else {
+                let direction = (target_pos - transform.translation).normalize();
+                transform.translation += direction * MOVE_SPEED * dt;
+            }
+        } else {
+            *moving_state = MovingState::Idle;
+        }
+    }
+}
+
+fn update_pom(asset_server: Res<AssetServer>, mut query: Query<(&MovingState, &mut AseAnimation)>) {
+    for (moving_state, mut animation) in query.iter_mut() {
+        match moving_state {
+            MovingState::Idle => {
+                *animation = AseAnimation {
+                    aseprite: asset_server.load("pom/pom-sleep.aseprite"),
+                    animation: Animation::tag("sleep-sit-start").with_repeat(AnimationRepeat::Loop),
+                };
+            }
+            s if s.is_moving() => {
+                *animation = AseAnimation {
+                    aseprite: asset_server.load("pom/pom-walk.aseprite"),
+                    animation: (match s {
+                        MovingState::MovingUp => Animation::tag("walk_up"),
+                        MovingState::MovingDown => Animation::tag("walk_down"),
+                        MovingState::MovingLeft => Animation::tag("walk_left"),
+                        MovingState::MovingRight => Animation::tag("walk_right"),
+                        _ => panic!("This shouldn't be reachable"),
+                    })
+                    .with_repeat(AnimationRepeat::Loop),
+                };
+            }
+            _ => (),
+        }
+    }
+}

src/utils/mod.rs

@@ -0,0 +1 @@
+pub mod pathfinding;

src/utils/pathfinding.rs

@@ -0,0 +1,107 @@
+use crate::components::tile::{Grid, TileState};
+use bevy::prelude::*;
+use std::cmp::Ordering;
+use std::collections::{BinaryHeap, HashMap, VecDeque};
+
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub struct Node {
+    x: u32,
+    y: u32,
+    cost: u32,     // G score (distance from start)
+    priority: u32, // F score (G + H)
+}
+
+impl Ord for Node {
+    fn cmp(&self, other: &Self) -> Ordering {
+        other
+            .priority
+            .cmp(&self.priority)
+            .then_with(|| self.cost.cmp(&other.cost))
+    }
+}
+
+impl PartialOrd for Node {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+pub fn manhattan_distance(x1: u32, y1: u32, x2: u32, y2: u32) -> u32 {
+    (x1 as i32 - x2 as i32).abs() as u32 + (y1 as i32 - y2 as i32).abs() as u32
+}
+
+pub fn find_path(
+    start: (u32, u32),
+    end: (u32, u32),
+    grid: &Grid,
+    tile_query: &Query<&TileState>,
+) -> Option<VecDeque<(u32, u32)>> {
+    println!("find_path");
+
+    let target_entity = grid.get_tile(end).ok()?;
+    let state = tile_query.get(target_entity).unwrap();
+    if (*state).is_blocking() {
+        return None;
+    }
+
+    let mut open_set = BinaryHeap::new();
+    let mut came_from: HashMap<(u32, u32), (u32, u32)> = HashMap::new();
+    let mut g_score: HashMap<(u32, u32), u32> = HashMap::new();
+
+    g_score.insert(start, 0);
+    open_set.push(Node {
+        x: start.0,
+        y: start.1,
+        cost: 0,
+        priority: manhattan_distance(start.0, start.1, end.0, end.1),
+    });
+
+    while let Some(current) = open_set.pop() {
+        let current_pos = (current.x, current.y);
+
+        if current_pos == end {
+            let mut path = VecDeque::new();
+            let mut curr = end;
+            while curr != start {
+                path.push_front(curr);
+                curr = *came_from.get(&curr).unwrap();
+            }
+            return Some(path);
+        }
+
+        let neighbors = [
+            (current.x as i32 + 1, current.y as i32),
+            (current.x as i32 - 1, current.y as i32),
+            (current.x as i32, current.y as i32 + 1),
+            (current.x as i32, current.y as i32 - 1),
+        ];
+
+        for (nx, ny) in neighbors {
+            if nx < 0 || ny < 0 {
+                continue;
+            }
+            let next_pos = (nx as u32, ny as u32);
+
+            let tile_entity = grid.get_tile(next_pos).ok()?;
+            let state = tile_query.get(tile_entity).unwrap();
+            if (*state).is_blocking() {
+                continue;
+            }
+
+            let tentative_g_score = g_score.get(&current_pos).unwrap() + 1;
+            if tentative_g_score < *g_score.get(&next_pos).unwrap_or(&u32::MAX) {
+                came_from.insert(next_pos, current_pos);
+                g_score.insert(next_pos, tentative_g_score);
+                open_set.push(Node {
+                    x: next_pos.0,
+                    y: next_pos.1,
+                    cost: tentative_g_score,
+                    priority: tentative_g_score
+                        + manhattan_distance(next_pos.0, next_pos.1, end.0, end.1),
+                });
+            }
+        }
+    }
+
+    None
+}