feat: implement entity-based sprite system for HUD display (lives)

- Spawn HUD elements as Renderables with simple change-based entity updates
- Updated rendering systems to accommodate new precise pixel positioning for life sprites.

Cargo.lock

@@ -663,7 +663,7 @@ checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
 
 [[package]]
 name = "pacman"
-version = "0.78.0"
+version = "0.78.2"
 dependencies = [
  "anyhow",
  "bevy_ecs",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pacman"
-version = "0.78.0"
+version = "0.78.2"
 authors = ["Xevion"]
 edition = "2021"
 rust-version = "1.86.0"

src/constants.rs

@@ -25,12 +25,25 @@ pub const SCALE: f32 = 2.6;
 /// screen for score display, player lives, and other UI elements.
 pub const BOARD_CELL_OFFSET: UVec2 = UVec2::new(0, 3);
 
+/// Bottom HUD row offset to reserve space below the game board.
+///
+/// The 2-cell vertical offset (16 pixels) provides space at the bottom of the
+/// screen for displaying Pac-Man's lives (left) and fruit symbols (right).
+pub const BOARD_BOTTOM_CELL_OFFSET: UVec2 = UVec2::new(0, 2);
+
 /// Pixel-space equivalent of `BOARD_CELL_OFFSET` for rendering calculations.
 ///
 /// Automatically calculated from the cell offset to maintain consistency
 /// when the cell size changes. Used for positioning sprites and debug overlays.
 pub const BOARD_PIXEL_OFFSET: UVec2 = UVec2::new(BOARD_CELL_OFFSET.x * CELL_SIZE, BOARD_CELL_OFFSET.y * CELL_SIZE);
 
+/// Pixel-space equivalent of `BOARD_BOTTOM_CELL_OFFSET` for rendering calculations.
+///
+/// Automatically calculated from the cell offset to maintain consistency
+/// when the cell size changes. Used for positioning bottom HUD elements.
+pub const BOARD_BOTTOM_PIXEL_OFFSET: UVec2 =
+    UVec2::new(BOARD_BOTTOM_CELL_OFFSET.x * CELL_SIZE, BOARD_BOTTOM_CELL_OFFSET.y * CELL_SIZE);
+
 /// Animation timing constants for ghost state management
 pub mod animation {
     /// Normal ghost movement animation speed (ticks per frame at 60 ticks/sec)
@@ -45,15 +58,15 @@ pub mod animation {
 }
 /// The size of the canvas, in pixels.
 pub const CANVAS_SIZE: UVec2 = UVec2::new(
-    (BOARD_CELL_SIZE.x + BOARD_CELL_OFFSET.x) * CELL_SIZE,
-    (BOARD_CELL_SIZE.y + BOARD_CELL_OFFSET.y) * CELL_SIZE,
+    (BOARD_CELL_SIZE.x + BOARD_CELL_OFFSET.x + BOARD_BOTTOM_CELL_OFFSET.x) * CELL_SIZE,
+    (BOARD_CELL_SIZE.y + BOARD_CELL_OFFSET.y + BOARD_BOTTOM_CELL_OFFSET.y) * CELL_SIZE,
 );
 
 pub const LARGE_SCALE: f32 = 2.6;
 
 pub const LARGE_CANVAS_SIZE: UVec2 = UVec2::new(
-    (((BOARD_CELL_SIZE.x + BOARD_CELL_OFFSET.x) * CELL_SIZE) as f32 * LARGE_SCALE) as u32,
-    (((BOARD_CELL_SIZE.y + BOARD_CELL_OFFSET.y) * CELL_SIZE) as f32 * LARGE_SCALE) as u32,
+    (((BOARD_CELL_SIZE.x + BOARD_CELL_OFFSET.x + BOARD_BOTTOM_CELL_OFFSET.x) * CELL_SIZE) as f32 * LARGE_SCALE) as u32,
+    (((BOARD_CELL_SIZE.y + BOARD_CELL_OFFSET.y + BOARD_BOTTOM_CELL_OFFSET.y) * CELL_SIZE) as f32 * LARGE_SCALE) as u32,
 );
 
 /// Collider size constants for different entity types

src/game.rs

@@ -13,13 +13,13 @@ use crate::map::direction::Direction;
 use crate::systems::{
     self, audio_system, blinking_system, collision_system, combined_render_system, directional_render_system,
     dirty_render_system, eaten_ghost_system, ghost_collision_system, ghost_movement_system, ghost_state_system,
-    hud_render_system, item_system, linear_render_system, present_system, profile, time_to_live_system, touch_ui_render_system,
-    AudioEvent, AudioResource, AudioState, BackbufferResource, Blinking, BufferedDirection, Collider, DebugState,
-    DebugTextureResource, DeltaTime, DirectionalAnimation, EntityType, Frozen, GameStage, Ghost, GhostAnimation, GhostAnimations,
-    GhostBundle, GhostCollider, GhostState, GlobalState, Hidden, ItemBundle, ItemCollider, LastAnimationState, LinearAnimation,
-    MapTextureResource, MovementModifiers, NodeId, PacmanCollider, PlayerAnimation, PlayerBundle, PlayerControlled,
-    PlayerDeathAnimation, PlayerLives, Position, RenderDirty, Renderable, ScoreResource, StartupSequence, SystemId,
-    SystemTimings, Timing, TouchState, Velocity,
+    hud_render_system, item_system, linear_render_system, player_life_sprite_system, present_system, profile,
+    time_to_live_system, touch_ui_render_system, AudioEvent, AudioResource, AudioState, BackbufferResource, Blinking,
+    BufferedDirection, Collider, DebugState, DebugTextureResource, DeltaTime, DirectionalAnimation, EntityType, Frozen,
+    GameStage, Ghost, GhostAnimation, GhostAnimations, GhostBundle, GhostCollider, GhostState, GlobalState, Hidden, ItemBundle,
+    ItemCollider, LastAnimationState, LinearAnimation, MapTextureResource, MovementModifiers, NodeId, PacmanCollider,
+    PlayerAnimation, PlayerBundle, PlayerControlled, PlayerDeathAnimation, PlayerLives, Position, RenderDirty, Renderable,
+    ScoreResource, StartupSequence, SystemId, SystemTimings, Timing, TouchState, Velocity,
 };
 
 use crate::texture::animated::{DirectionalTiles, TileSequence};
@@ -449,10 +449,9 @@ impl Game {
         let linear_render_system = profile(SystemId::LinearRender, linear_render_system);
         let dirty_render_system = profile(SystemId::DirtyRender, dirty_render_system);
         let hud_render_system = profile(SystemId::HudRender, hud_render_system);
+        let player_life_sprite_system = profile(SystemId::HudRender, player_life_sprite_system);
         let present_system = profile(SystemId::Present, present_system);
         let unified_ghost_state_system = profile(SystemId::GhostStateAnimation, ghost_state_system);
-        // let death_sequence_system = profile(SystemId::DeathSequence, death_sequence_system);
-        // let game_over_system = profile(SystemId::GameOver, systems::game_over_system);
         let eaten_ghost_system = profile(SystemId::EatenGhost, eaten_ghost_system);
         let time_to_live_system = profile(SystemId::TimeToLive, time_to_live_system);
 
@@ -460,10 +459,8 @@ impl Game {
             dirty.0 = true;
         };
 
-        schedule.add_systems(
-            forced_dirty_system
-                .run_if(|score: Res<ScoreResource>, stage: Res<GameStage>| score.is_changed() || stage.is_changed()),
-        );
+        schedule.add_systems((forced_dirty_system
+            .run_if(|score: Res<ScoreResource>, stage: Res<GameStage>| score.is_changed() || stage.is_changed()),));
 
         // Input system should always run to prevent SDL event pump from blocking
         let input_systems = (
@@ -496,6 +493,7 @@ impl Game {
                 dirty_render_system,
                 combined_render_system,
                 hud_render_system,
+                player_life_sprite_system,
                 touch_ui_render_system,
                 present_system,
             )

src/systems/components.rs

@@ -229,6 +229,14 @@ pub struct Eaten;
 #[derive(Component, Debug, Clone, Copy)]
 pub struct Dying;
 
+/// Component for HUD life sprite entities.
+/// Each life sprite entity has an index indicating its position from left to right (0, 1, 2, etc.).
+/// This mostly functions as a tag component for sprites.
+#[derive(Component, Debug, Clone, Copy)]
+pub struct PlayerLife {
+    pub index: u32,
+}
+
 #[derive(Component, Debug, Clone, Copy)]
 pub enum GhostState {
     /// Normal ghost behavior - chasing Pac-Man

src/systems/render.rs

@@ -1,14 +1,16 @@
 use crate::map::builder::Map;
+use crate::map::direction::Direction;
 use crate::systems::input::TouchState;
 use crate::systems::{
     debug_render_system, BatchedLinesResource, Collider, CursorPosition, DebugState, DebugTextureResource, DeltaTime,
-    DirectionalAnimation, Dying, Frozen, GameStage, LinearAnimation, Looping, PlayerLives, Position, Renderable, ScoreResource,
-    StartupSequence, SystemId, SystemTimings, TtfAtlasResource, Velocity,
+    DirectionalAnimation, Dying, Frozen, GameStage, LinearAnimation, Looping, PlayerLife, PlayerLives, Position, Renderable,
+    ScoreResource, StartupSequence, SystemId, SystemTimings, TtfAtlasResource, Velocity,
 };
 use crate::texture::sprite::SpriteAtlas;
+use crate::texture::sprites::{GameSprite, PacmanSprite};
 use crate::texture::text::TextTexture;
 use crate::{
-    constants::CANVAS_SIZE,
+    constants::{BOARD_BOTTOM_PIXEL_OFFSET, CANVAS_SIZE, CELL_SIZE},
     error::{GameError, TextureError},
 };
 use bevy_ecs::component::Component;
@@ -17,7 +19,8 @@ use bevy_ecs::event::EventWriter;
 use bevy_ecs::query::{Changed, Has, Or, With, Without};
 use bevy_ecs::removal_detection::RemovedComponents;
 use bevy_ecs::resource::Resource;
-use bevy_ecs::system::{NonSendMut, Query, Res, ResMut};
+use bevy_ecs::system::{Commands, NonSendMut, Query, Res, ResMut};
+use glam::Vec2;
 use sdl2::pixels::Color;
 use sdl2::rect::{Point, Rect};
 use sdl2::render::{BlendMode, Canvas, Texture};
@@ -124,6 +127,84 @@ pub fn linear_render_system(
     }
 }
 
+/// System that manages player life sprite entities.
+/// Spawns and despawns life sprite entities based on changes to PlayerLives resource.
+/// Each life sprite is positioned based on its index (0, 1, 2, etc. from left to right).
+pub fn player_life_sprite_system(
+    mut commands: Commands,
+    atlas: NonSendMut<SpriteAtlas>,
+    current_life_sprites: Query<(Entity, &PlayerLife)>,
+    player_lives: Res<PlayerLives>,
+    mut errors: EventWriter<GameError>,
+) {
+    let displayed_lives = player_lives.0.saturating_sub(1);
+
+    // Get current life sprite entities, sorted by index
+    let mut current_sprites: Vec<_> = current_life_sprites.iter().collect();
+    current_sprites.sort_by_key(|(_, life)| life.index);
+    let current_count = current_sprites.len() as u8;
+
+    // Calculate the difference
+    let diff = (displayed_lives as i8) - (current_count as i8);
+
+    if diff > 0 {
+        // Spawn new life sprites
+        let life_sprite = match atlas.get_tile(&GameSprite::Pacman(PacmanSprite::Moving(Direction::Left, 1)).to_path()) {
+            Ok(sprite) => sprite,
+            Err(e) => {
+                errors.write(e.into());
+                return;
+            }
+        };
+
+        for i in 0..diff.abs() {
+            let position = calculate_life_sprite_position(i as u32);
+
+            commands.spawn((
+                PlayerLife { index: i as u32 },
+                Renderable {
+                    sprite: life_sprite,
+                    layer: 255, // High layer to render on top
+                },
+                PixelPosition {
+                    pixel_position: position,
+                },
+            ));
+        }
+    } else if diff < 0 {
+        // Remove excess life sprites (highest indices first)
+        let to_remove = diff.abs() as usize;
+        let sprites_to_remove: Vec<_> = current_sprites
+            .iter()
+            .rev() // Start from highest index
+            .take(to_remove as usize)
+            .map(|(entity, _)| *entity)
+            .collect();
+
+        for entity in sprites_to_remove {
+            commands.entity(entity).despawn();
+        }
+    }
+}
+
+/// Component for Renderables to store an exact pixel position
+#[derive(Component)]
+pub struct PixelPosition {
+    pub pixel_position: Vec2,
+}
+
+/// Calculates the pixel position for a life sprite based on its index
+fn calculate_life_sprite_position(index: u32) -> Vec2 {
+    let start_x = CELL_SIZE * 2; // 2 cells from left
+    let start_y = CANVAS_SIZE.y - BOARD_BOTTOM_PIXEL_OFFSET.y + (CELL_SIZE / 2) + 1; // In bottom area
+    let sprite_spacing = CELL_SIZE + CELL_SIZE / 2; // 1.5 cells between sprites
+
+    let x = start_x + ((index as f32) * (sprite_spacing as f32 * 1.5)).round() as u32;
+    let y = start_y - CELL_SIZE / 2;
+
+    Vec2::new((x + CELL_SIZE) as f32, (y + CELL_SIZE) as f32)
+}
+
 /// A non-send resource for the map texture. This just wraps the texture with a type so it can be differentiated when exposed as a resource.
 pub struct MapTextureResource(pub Texture);
 
@@ -209,7 +290,6 @@ pub fn hud_render_system(
     mut backbuffer: NonSendMut<BackbufferResource>,
     mut canvas: NonSendMut<&mut Canvas<Window>>,
     mut atlas: NonSendMut<SpriteAtlas>,
-    player_lives: Res<PlayerLives>,
     score: Res<ScoreResource>,
     stage: Res<GameStage>,
     mut errors: EventWriter<GameError>,
@@ -218,11 +298,10 @@ pub fn hud_render_system(
         let mut text_renderer = TextTexture::new(1.0);
 
         // Render lives and high score text in white
-        let lives = player_lives.0;
-        let lives_text = format!("{lives}UP   HIGH SCORE   ");
+        let lives_text = "1UP   HIGH SCORE   ";
         let lives_position = glam::UVec2::new(4 + 8 * 3, 2); // x_offset + lives_offset * 8, y_offset
 
-        if let Err(e) = text_renderer.render(canvas, &mut atlas, &lives_text, lives_position) {
+        if let Err(e) = text_renderer.render(canvas, &mut atlas, lives_text, lives_position) {
             errors.write(TextureError::RenderFailed(format!("Failed to render lives text: {}", e)).into());
         }
 
@@ -288,7 +367,10 @@ pub fn render_system(
     atlas: &mut SpriteAtlas,
     map: &Res<Map>,
     dirty: &Res<RenderDirty>,
-    renderables: &Query<(Entity, &Renderable, &Position), Without<Hidden>>,
+    renderables: &Query<
+        (Entity, &Renderable, Option<&Position>, Option<&PixelPosition>),
+        (Without<Hidden>, Or<(With<Position>, With<PixelPosition>)>),
+    >,
     errors: &mut EventWriter<GameError>,
 ) {
     if !dirty.0 {
@@ -305,12 +387,21 @@ pub fn render_system(
     }
 
     // Render all entities to the backbuffer
-    for (_, renderable, position) in renderables
+    for (_entity, renderable, position, pixel_position) in renderables
         .iter()
-        .sort_by_key::<(Entity, &Renderable, &Position), _>(|(_, renderable, _)| renderable.layer)
+        .sort_by_key::<(Entity, &Renderable, Option<&Position>, Option<&PixelPosition>), _>(|(_, renderable, _, _)| {
+            renderable.layer
+        })
         .rev()
     {
-        let pos = position.get_pixel_position(&map.graph);
+        let pos = if let Some(position) = position {
+            position.get_pixel_position(&map.graph)
+        } else {
+            Ok(pixel_position
+                .expect("Pixel position should be present via query filtering, but got None on both")
+                .pixel_position)
+        };
+
         match pos {
             Ok(pos) => {
                 let dest = Rect::from_center(
@@ -348,7 +439,10 @@ pub fn combined_render_system(
     timing: Res<crate::systems::profiling::Timing>,
     map: Res<Map>,
     dirty: Res<RenderDirty>,
-    renderables: Query<(Entity, &Renderable, &Position), Without<Hidden>>,
+    renderables: Query<
+        (Entity, &Renderable, Option<&Position>, Option<&PixelPosition>),
+        (Without<Hidden>, Or<(With<Position>, With<PixelPosition>)>),
+    >,
     colliders: Query<(&Collider, &Position)>,
     cursor: Res<CursorPosition>,
     mut errors: EventWriter<GameError>,