docs: document many major functions, types, enums for important functionality

src/app.rs

@@ -12,6 +12,11 @@ use crate::constants::{CANVAS_SIZE, LOOP_TIME, SCALE};
 use crate::game::Game;
 use crate::platform::get_platform;
 
+/// Main application wrapper that manages SDL initialization, window lifecycle, and the game loop.
+///
+/// Handles platform-specific setup, maintains consistent frame timing, and delegates
+/// game logic to the contained `Game` instance. The app manages focus state to
+/// optimize CPU usage when the window loses focus.
 pub struct App {
     pub game: Game,
     last_tick: Instant,
@@ -20,6 +25,16 @@ pub struct App {
 }
 
 impl App {
+    /// Initializes SDL subsystems, creates the game window, and sets up the game state.
+    ///
+    /// Performs comprehensive initialization including video/audio subsystems, platform-specific
+    /// console setup, window creation with proper scaling, and canvas configuration. All SDL
+    /// resources are leaked to maintain 'static lifetimes required by the game architecture.
+    ///
+    /// # Errors
+    ///
+    /// Returns `GameError::Sdl` if any SDL initialization step fails, or propagates
+    /// errors from `Game::new()` during game state setup.
     pub fn new() -> GameResult<Self> {
         let sdl_context: &'static Sdl = Box::leak(Box::new(sdl2::init().map_err(|e| GameError::Sdl(e.to_string()))?));
         let video_subsystem: &'static VideoSubsystem =
@@ -70,6 +85,16 @@ impl App {
         })
     }
 
+    /// Executes a single frame of the game loop with consistent timing and optional sleep.
+    ///
+    /// Calculates delta time since the last frame, runs game logic via `game.tick()`,
+    /// and implements frame rate limiting by sleeping for remaining time if the frame
+    /// completed faster than the target `LOOP_TIME`. Sleep behavior varies based on
+    /// window focus to conserve CPU when the game is not active.
+    ///
+    /// # Returns
+    ///
+    /// `true` if the game should continue running, `false` if the game requested exit.
     pub fn run(&mut self) -> bool {
         {
             let start = Instant::now();

src/asset.rs

@@ -5,17 +5,28 @@
 use std::borrow::Cow;
 use strum_macros::EnumIter;
 
+/// Enumeration of all game assets with cross-platform loading support.
+///
+/// Each variant corresponds to a specific file that can be loaded either from
+/// binary-embedded data or embedded filesystem (Emscripten).
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, EnumIter)]
 pub enum Asset {
     Wav1,
     Wav2,
     Wav3,
     Wav4,
+    /// Main sprite atlas containing all game graphics (atlas.png)
     AtlasImage,
+    /// Terminal Vector font for text rendering (TerminalVector.ttf)
     Font,
 }
 
 impl Asset {
+    /// Returns the relative file path for this asset within the game's asset directory.
+    ///
+    /// Paths are consistent across platforms and used by the Emscripten backend
+    /// for filesystem loading. Desktop builds embed assets directly and don't
+    /// use these paths at runtime.
     #[allow(dead_code)]
     pub fn path(&self) -> &str {
         use Asset::*;
@@ -35,7 +46,17 @@ mod imp {
     use crate::error::AssetError;
     use crate::platform::get_platform;
 
-    /// Returns the raw bytes of the given asset.
+    /// Loads asset bytes using the appropriate platform-specific method.
+    ///
+    /// On desktop platforms, returns embedded compile-time data via `include_bytes!`.
+    /// On Emscripten, loads from the filesystem using the asset's path. The returned
+    /// `Cow` allows zero-copy access to embedded data while supporting owned data
+    /// when loaded from disk.
+    ///
+    /// # Errors
+    ///
+    /// Returns `AssetError::NotFound` if the asset file cannot be located (Emscripten only),
+    /// or `AssetError::Io` for filesystem I/O failures.
     pub fn get_asset_bytes(asset: Asset) -> Result<Cow<'static, [u8]>, AssetError> {
         get_platform().get_asset_bytes(asset)
     }

src/audio.rs

@@ -114,9 +114,11 @@ impl Audio {
         }
     }
 
-    /// Plays the "eat" sound effect.
+    /// Plays the next waka eating sound in the cycle of four variants.
     ///
-    /// If audio is disabled or muted, this function does nothing.
+    /// Automatically rotates through the four eating sound assets. The sound plays on channel 0 and the internal sound index
+    /// advances to the next variant. Silently returns if audio is disabled, muted,
+    /// or no sounds were loaded successfully.
     #[allow(dead_code)]
     pub fn eat(&mut self) {
         if self.disabled || self.muted || self.sounds.is_empty() {
@@ -136,9 +138,11 @@ impl Audio {
         self.next_sound_index = (self.next_sound_index + 1) % self.sounds.len();
     }
 
-    /// Instantly mute or unmute all channels.
+    /// Instantly mutes or unmutes all audio channels by adjusting their volume.
     ///
-    /// If audio is disabled, this function does nothing.
+    /// Sets all 4 mixer channels to zero volume when muting, or restores them to
+    /// their default volume (32) when unmuting. The mute state is tracked internally
+    /// regardless of whether audio is disabled, allowing the state to be preserved.
     pub fn set_mute(&mut self, mute: bool) {
         if !self.disabled {
             let channels = 4;
@@ -151,12 +155,19 @@ impl Audio {
         self.muted = mute;
     }
 
-    /// Returns `true` if the audio is muted.
+    /// Returns the current mute state regardless of whether audio is functional.
+    ///
+    /// This tracks the user's mute preference and will return `true` if muted
+    /// even when the audio system is disabled due to initialization failures.
     pub fn is_muted(&self) -> bool {
         self.muted
     }
 
-    /// Returns `true` if the audio system is disabled.
+    /// Returns whether the audio system failed to initialize and is non-functional.
+    ///
+    /// Audio can be disabled due to SDL2_mixer initialization failures, missing
+    /// audio device, or failure to load any sound assets. When disabled, all
+    /// audio operations become no-ops.
     #[allow(dead_code)]
     pub fn is_disabled(&self) -> bool {
         self.disabled

src/constants.rs

@@ -4,6 +4,11 @@ use std::time::Duration;
 
 use glam::UVec2;
 
+/// Target frame duration for 60 FPS game loop timing.
+///
+/// Calculated as 1/60th of a second (≈16.67ms).
+///
+/// Written out explicitly to satisfy const-eval constraints.
 pub const LOOP_TIME: Duration = Duration::from_nanos((1_000_000_000.0 / 60.0) as u64);
 
 /// The size of each cell, in pixels.
@@ -14,9 +19,16 @@ pub const BOARD_CELL_SIZE: UVec2 = UVec2::new(28, 31);
 /// The scale factor for the window (integer zoom)
 pub const SCALE: f32 = 2.6;
 
-/// The offset of the game board from the top-left corner of the window, in cells.
+/// Game board offset from window origin to reserve space for HUD elements.
+///
+/// The 3-cell vertical offset (24 pixels) provides space at the top of the
+/// screen for score display, player lives, and other UI elements.
 pub const BOARD_CELL_OFFSET: UVec2 = UVec2::new(0, 3);
-/// The offset of the game board from the top-left corner of the window, in pixels.
+
+/// 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);
 /// The size of the canvas, in pixels.
 pub const CANVAS_SIZE: UVec2 = UVec2::new(
@@ -24,22 +36,24 @@ pub const CANVAS_SIZE: UVec2 = UVec2::new(
     (BOARD_CELL_SIZE.y + BOARD_CELL_OFFSET.y) * CELL_SIZE,
 );
 
-/// An enum representing the different types of tiles on the map.
+/// Map tile types that define gameplay behavior and collision properties.
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum MapTile {
-    /// An empty tile.
+    /// Traversable space with no collectible items
     Empty,
-    /// A wall tile.
     Wall,
-    /// A regular pellet.
+    /// Small collectible. Implicitly a traversable tile.
     Pellet,
-    /// A power pellet.
+    /// Large collectible. Implicitly a traversable tile.
     PowerPellet,
-    /// A tunnel tile.
+    /// Special traversable tile that connects to tunnel portals.
     Tunnel,
 }
 
-/// The raw layout of the game board, as a 2D array of characters.
+/// ASCII art representation of the classic Pac-Man maze layout.
+///
+/// Uses character symbols to define the game world. This layout is parsed by `MapTileParser`
+/// to generate the navigable graph and collision geometry.
 pub const RAW_BOARD: [&str; BOARD_CELL_SIZE.y as usize] = [
     "############################",
     "#............##............#",

src/events.rs

@@ -2,19 +2,36 @@ use bevy_ecs::{entity::Entity, event::Event};
 
 use crate::map::direction::Direction;
 
+/// Player input commands that trigger specific game actions.
+///
+/// Commands are generated by the input system in response to keyboard events
+/// and processed by appropriate game systems to modify state or behavior.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum GameCommand {
+    /// Request immediate game shutdown
     Exit,
+    /// Set Pac-Man's movement direction
     MovePlayer(Direction),
+    /// Cycle through debug visualization modes
     ToggleDebug,
+    /// Toggle audio mute state
     MuteAudio,
+    /// Restart the current level with fresh entity positions and items
     ResetLevel,
+    /// Pause or resume game ticking logic
     TogglePause,
 }
 
+/// Global events that flow through the ECS event system to coordinate game behavior.
+///
+/// Events enable loose coupling between systems - input generates commands, collision
+/// detection reports overlaps, and various systems respond appropriately without
+/// direct dependencies.
 #[derive(Event, Clone, Copy, Debug, PartialEq, Eq)]
 pub enum GameEvent {
+    /// Player input command to be processed by relevant game systems
     Command(GameCommand),
+    /// Physical overlap detected between two entities requiring gameplay response
     Collision(Entity, Entity),
 }
 

src/game.rs

@@ -48,16 +48,37 @@ use crate::{
     texture::sprite::{AtlasMapper, SpriteAtlas},
 };
 
-/// The `Game` struct is the main entry point for the game.
+/// Core game state manager built on the Bevy ECS architecture.
 ///
-/// It contains the game's state and logic, and is responsible for
-/// handling user input, updating the game state, and rendering the game.
+/// Orchestrates all game systems through a centralized `World` containing entities,
+/// components, and resources, while a `Schedule` defines system execution order.
+/// Handles initialization of graphics resources, entity spawning, and per-frame
+/// game logic coordination. SDL2 resources are stored as `NonSend` to respect
+/// thread safety requirements while integrating with the ECS.
 pub struct Game {
     pub world: World,
     pub schedule: Schedule,
 }
 
 impl Game {
+    /// Initializes the complete game state including ECS world, graphics, and entity spawning.
+    ///
+    /// Performs extensive setup: creates render targets and debug textures, loads and parses
+    /// the sprite atlas, renders the static map to a cached texture, builds the navigation
+    /// graph from the board layout, spawns Pac-Man with directional animations, creates
+    /// all four ghosts with their AI behavior, and places collectible items throughout
+    /// the maze. Registers event types and configures the system execution schedule.
+    ///
+    /// # Arguments
+    ///
+    /// * `canvas` - SDL2 rendering context with static lifetime for ECS storage
+    /// * `texture_creator` - SDL2 texture factory for creating render targets
+    /// * `event_pump` - SDL2 event polling interface for input handling
+    ///
+    /// # Errors
+    ///
+    /// Returns `GameError` for SDL2 failures, asset loading problems, atlas parsing
+    /// errors, or entity initialization issues.
     pub fn new(
         canvas: &'static mut Canvas<Window>,
         texture_creator: &'static mut TextureCreator<WindowContext>,
@@ -289,7 +310,12 @@ impl Game {
         Ok(Game { world, schedule })
     }
 
-    /// Spowns all four ghosts at their starting positions with appropriate textures.
+    /// Creates and spawns all four ghosts with unique AI personalities and directional animations.
+    ///
+    /// # Errors
+    ///
+    /// Returns `GameError::Texture` if any ghost sprite cannot be found in the atlas,
+    /// typically indicating missing or misnamed sprite files.
     fn spawn_ghosts(world: &mut World) -> GameResult<()> {
         // Extract the data we need first to avoid borrow conflicts
         let ghost_start_positions = {
@@ -394,9 +420,21 @@ impl Game {
         Ok(())
     }
 
-    /// Ticks the game state.
+    /// Executes one frame of game logic by running all scheduled ECS systems.
     ///
-    /// Returns true if the game should exit.
+    /// Updates the world's delta time resource and runs the complete system pipeline:
+    /// input processing, entity movement, collision detection, item collection,
+    /// audio playback, animation updates, and rendering. Each system operates on
+    /// relevant entities and modifies world state, with the schedule ensuring
+    /// proper execution order and data dependencies.
+    ///
+    /// # Arguments
+    ///
+    /// * `dt` - Frame delta time in seconds for time-based animations and movement
+    ///
+    /// # Returns
+    ///
+    /// `true` if the game should terminate (exit command received), `false` to continue
     pub fn tick(&mut self, dt: f32) -> bool {
         self.world.insert_resource(DeltaTime(dt));
 

src/map/builder.rs

@@ -11,25 +11,37 @@ use tracing::debug;
 
 use crate::error::{GameResult, MapError};
 
-/// The starting positions of the entities in the game.
+/// Predefined spawn locations for all game entities within the navigation graph.
+///
+/// These positions are determined during map parsing and graph construction.
 pub struct NodePositions {
+    /// Pac-Man's starting position in the lower section of the maze
     pub pacman: NodeId,
+    /// Blinky starts at the ghost house entrance
     pub blinky: NodeId,
+    /// Pinky starts in the left area of the ghost house
     pub pinky: NodeId,
+    /// Inky starts in the right area of the ghost house
     pub inky: NodeId,
+    /// Clyde starts in the center of the ghost house
     pub clyde: NodeId,
 }
 
-/// The main map structure containing the game board and navigation graph.
+/// Complete maze representation combining visual layout with navigation pathfinding.
+///
+/// Transforms the ASCII board layout into a fully connected navigation graph
+/// while preserving tile-based collision and rendering data. The graph enables
+/// smooth entity movement with proper pathfinding, while the grid mapping allows
+/// efficient spatial queries and debug visualization.
 #[derive(Resource)]
 pub struct Map {
-    /// The node map for entity movement.
+    /// Connected graph of navigable positions.
     pub graph: Graph,
-    /// A mapping from grid positions to node IDs.
+    /// Bidirectional mapping between 2D grid coordinates and graph node indices.
     pub grid_to_node: HashMap<IVec2, NodeId>,
-    /// A mapping of the starting positions of the entities.
+    /// Predetermined spawn locations for all game entities
     pub start_positions: NodePositions,
-    /// The raw tile data for the map.
+    /// 2D array of tile types for collision detection and rendering
     tiles: [[MapTile; BOARD_CELL_SIZE.y as usize]; BOARD_CELL_SIZE.x as usize],
 }
 
@@ -162,7 +174,18 @@ impl Map {
         })
     }
 
-    /// Builds the house structure in the graph.
+    /// Constructs the ghost house area with restricted access and internal navigation.
+    ///
+    /// Creates a multi-level ghost house with entrance control, internal movement
+    /// areas, and starting positions for each ghost. The house entrance uses
+    /// ghost-only traversal flags to prevent Pac-Man from entering while allowing
+    /// ghosts to exit. Internal nodes are arranged in vertical lines to provide
+    /// distinct starting areas for each ghost character.
+    ///
+    /// # Returns
+    ///
+    /// Tuple of node IDs: (house_entrance, left_center, center_center, right_center)
+    /// representing the four key positions within the ghost house structure.
     fn build_house(
         graph: &mut Graph,
         grid_to_node: &HashMap<IVec2, NodeId>,
@@ -296,7 +319,10 @@ impl Map {
         ))
     }
 
-    /// Builds the tunnel connections in the graph.
+    /// Creates horizontal tunnel portals for instant teleportation across the maze.
+    ///
+    /// Establishes the tunnel system that allows entities to instantly travel from the left edge of the maze to the right edge.
+    /// Creates hidden intermediate nodes beyond the visible tunnel entrances and connects them with zero-distance edges for instantaneous traversal.
     fn build_tunnels(
         graph: &mut Graph,
         grid_to_node: &HashMap<IVec2, NodeId>,

src/map/parser.rs

@@ -4,16 +4,21 @@ use crate::constants::{MapTile, BOARD_CELL_SIZE};
 use crate::error::ParseError;
 use glam::IVec2;
 
-/// Represents the parsed data from a raw board layout.
+/// Structured representation of parsed ASCII board layout with extracted special positions.
+///
+/// Contains the complete board state after character-to-tile conversion, along with
+/// the locations of special gameplay elements that require additional processing
+/// during graph construction. Special positions are extracted during parsing to
+/// enable proper map builder initialization.
 #[derive(Debug)]
 pub struct ParsedMap {
-    /// The parsed tile layout.
+    /// 2D array of tiles converted from ASCII characters
     pub tiles: [[MapTile; BOARD_CELL_SIZE.y as usize]; BOARD_CELL_SIZE.x as usize],
-    /// The positions of the house door tiles.
+    /// Two positions marking the ghost house entrance (represented by '=' characters)
     pub house_door: [Option<IVec2>; 2],
-    /// The positions of the tunnel end tiles.
+    /// Two positions marking tunnel portals for wraparound teleportation ('T' characters)
     pub tunnel_ends: [Option<IVec2>; 2],
-    /// Pac-Man's starting position.
+    /// Starting position for Pac-Man (marked by 'X' character in the layout)
     pub pacman_start: Option<IVec2>,
 }
 
@@ -21,15 +26,18 @@ pub struct ParsedMap {
 pub struct MapTileParser;
 
 impl MapTileParser {
-    /// Parses a single character into a map tile.
+    /// Converts ASCII characters from the board layout into corresponding tile types.
     ///
-    /// # Arguments
+    /// Interprets the character-based maze representation: walls (`#`), collectible
+    /// pellets (`.` and `o`), traversable spaces (` `), tunnel entrances (`T`),
+    /// ghost house doors (`=`), and entity spawn markers (`X`). Special characters
+    /// that don't represent tiles in the final map (like spawn markers) are
+    /// converted to `Empty` tiles while their positions are tracked separately.
     ///
-    /// * `c` - The character to parse
+    /// # Errors
     ///
-    /// # Returns
-    ///
-    /// The parsed map tile, or an error if the character is unknown.
+    /// Returns `ParseError::UnknownCharacter` for any character not defined
+    /// in the game's ASCII art vocabulary.
     pub fn parse_character(c: char) -> Result<MapTile, ParseError> {
         match c {
             '#' => Ok(MapTile::Wall),

src/platform/mod.rs

@@ -10,29 +10,29 @@ mod desktop;
 #[cfg(target_os = "emscripten")]
 mod emscripten;
 
-/// Platform abstraction trait that defines cross-platform functionality.
+/// Cross-platform abstraction layer providing unified APIs for platform-specific operations.
 pub trait CommonPlatform {
-    /// Sleep for the specified duration using platform-appropriate method.
+    /// Platform-specific sleep function (required due to Emscripten's non-standard sleep requirements).
+    ///
+    /// Provides access to current window focus state, useful for changing sleep algorithm conditionally.
     fn sleep(&self, duration: Duration, focused: bool);
 
-    /// Get the current time in seconds since some reference point.
-    /// This is available for future use in timing and performance monitoring.
     #[allow(dead_code)]
     fn get_time(&self) -> f64;
 
-    /// Initialize platform-specific console functionality.
+    /// Configures platform-specific console and debugging output capabilities.
     fn init_console(&self) -> Result<(), PlatformError>;
 
-    /// Get canvas size for platforms that need it (e.g., Emscripten).
-    /// This is available for future use in responsive design.
+    /// Retrieves the actual display canvas dimensions.
     #[allow(dead_code)]
     fn get_canvas_size(&self) -> Option<(u32, u32)>;
 
-    /// Load asset bytes using platform-appropriate method.
+    /// Loads raw asset data using the appropriate platform-specific method.
+
     fn get_asset_bytes(&self, asset: Asset) -> Result<Cow<'static, [u8]>, AssetError>;
 }
 
-/// Get the current platform implementation.
+/// Returns the appropriate platform implementation based on compile-time target.
 #[allow(dead_code)]
 pub fn get_platform() -> &'static dyn CommonPlatform {
     #[cfg(not(target_os = "emscripten"))]

src/systems/collision.rs

@@ -9,6 +9,13 @@ use crate::map::builder::Map;
 use crate::systems::components::{Collider, ItemCollider, PacmanCollider};
 use crate::systems::movement::Position;
 
+/// Detects overlapping entities and generates collision events for gameplay systems.
+///
+/// Performs distance-based collision detection between Pac-Man and collectible items
+/// using each entity's position and collision radius. When entities overlap, emits
+/// a `GameEvent::Collision` for the item system to handle scoring and removal.
+/// Collision detection accounts for both entities being in motion and supports
+/// circular collision boundaries for accurate gameplay feel.
 pub fn collision_system(
     map: Res<Map>,
     pacman_query: Query<(Entity, &Position, &Collider), With<PacmanCollider>>,

src/systems/ghost.rs

@@ -14,10 +14,7 @@ use crate::{
     },
 };
 
-/// Ghost AI system that handles randomized movement decisions.
-///
-/// This system runs on all ghosts and makes periodic decisions about
-/// which direction to move in when they reach intersections.
+/// Autonomous ghost AI system implementing randomized movement with backtracking avoidance.
 pub fn ghost_movement_system(
     map: Res<Map>,
     delta_time: Res<DeltaTime>,

src/systems/movement.rs

@@ -4,7 +4,10 @@ use crate::map::graph::Graph;
 use bevy_ecs::component::Component;
 use glam::Vec2;
 
-/// A unique identifier for a node, represented by its index in the graph's storage.
+/// Zero-based index identifying a specific node in the navigation graph.
+///
+/// Nodes represent discrete movement targets in the maze. The index directly corresponds to the node's position in the
+/// graph's internal storage arrays.
 pub type NodeId = usize;
 
 /// A component that represents the speed and cardinal direction of an entity.
@@ -24,15 +27,19 @@ pub enum BufferedDirection {
     Some { direction: Direction, remaining_time: f32 },
 }
 
-/// Pure spatial position component - works for both static and dynamic entities.
+/// Entity position state that handles both stationary entities and moving entities.
+///
+/// Supports precise positioning during movement between discrete navigation nodes.
+/// When moving, entities smoothly interpolate along edges while tracking exact distance remaining to the target node.
 #[derive(Component, Debug, Copy, Clone, PartialEq)]
 pub enum Position {
-    Stopped {
-        node: NodeId,
-    },
+    /// Entity is stationary at a specific graph node.
+    Stopped { node: NodeId },
+    /// Entity is traveling between two nodes.
     Moving {
         from: NodeId,
         to: NodeId,
+        /// Distance remaining to reach the target node.
         remaining_distance: f32,
     },
 }
@@ -82,9 +89,21 @@ impl Position {
         ))
     }
 
-    /// Moves the position by a given distance towards it's current target node.
+    /// Advances movement progress by the specified distance with overflow handling.
     ///
-    /// Returns the overflow distance, if any.
+    /// For moving entities, decreases the remaining distance to the target node.
+    /// If the distance would overshoot the target, the entity transitions to
+    /// `Stopped` state and returns the excess distance for chaining movement
+    /// to the next edge in the same frame.
+    ///
+    /// # Arguments
+    ///
+    /// * `distance` - Distance to travel this frame (typically speed × delta_time)
+    ///
+    /// # Returns
+    ///
+    /// `Some(overflow)` if the target was reached with distance remaining,
+    /// `None` if still moving or already stopped.
     pub fn tick(&mut self, distance: f32) -> Option<f32> {
         if distance <= 0.0 || self.is_at_node() {
             return None;

src/systems/player.rs

@@ -17,7 +17,12 @@ use crate::{
     },
 };
 
-// Handles player input and control
+/// Processes player input commands and updates game state accordingly.
+///
+/// Handles keyboard-driven commands like movement direction changes, debug mode
+/// toggling, audio muting, and game exit requests. Movement commands are buffered
+/// to allow direction changes before reaching intersections, improving gameplay
+/// responsiveness. Non-movement commands immediately modify global game state.
 pub fn player_control_system(
     mut events: EventReader<GameEvent>,
     mut state: ResMut<GlobalState>,
@@ -69,6 +74,11 @@ fn can_traverse(entity_type: EntityType, edge: Edge) -> bool {
     edge.traversal_flags.contains(entity_flags)
 }
 
+/// Executes frame-by-frame movement for Pac-Man.
+///
+/// Handles movement logic including buffered direction changes, edge traversal validation, and continuous movement between nodes.
+/// When stopped, prioritizes buffered directions for responsive controls, falling back to current direction.
+/// Supports movement chaining within a single frame when traveling at high speeds.
 pub fn player_movement_system(
     map: Res<Map>,
     delta_time: Res<DeltaTime>,

src/texture/animated.rs

@@ -1,11 +1,19 @@
 use crate::error::{AnimatedTextureError, GameError, GameResult, TextureError};
 use crate::texture::sprite::AtlasTile;
 
+/// Frame-based animation system for cycling through multiple sprite tiles.
+///
+/// Manages automatic frame progression based on elapsed time.
+/// Uses a time banking system to ensure consistent animation speed regardless of frame rate variations.
 #[derive(Debug, Clone)]
 pub struct AnimatedTexture {
+    /// Sequence of sprite tiles that make up the animation frames
     tiles: Vec<AtlasTile>,
+    /// Duration each frame should be displayed (in seconds)
     frame_duration: f32,
+    /// Index of the currently active frame in the tiles vector
     current_frame: usize,
+    /// Accumulated time since the last frame change (for smooth timing)
     time_bank: f32,
 }
 
@@ -25,6 +33,16 @@ impl AnimatedTexture {
         })
     }
 
+    /// Advances the animation by the specified time delta with automatic frame cycling.
+    ///
+    /// Accumulates time in the time bank and progresses through frames when enough
+    /// time has elapsed. Supports frame rates independent of game frame rate by
+    /// potentially advancing multiple frames in a single call if `dt` is large.
+    /// Animation loops automatically when reaching the final frame.
+    ///
+    /// # Arguments
+    ///
+    /// * `dt` - Time elapsed since the last tick (typically frame delta time)
     pub fn tick(&mut self, dt: f32) {
         self.time_bank += dt;
         while self.time_bank >= self.frame_duration {

src/texture/sprite.rs

@@ -8,8 +8,10 @@ use std::collections::HashMap;
 
 use crate::error::TextureError;
 
+/// Atlas frame mapping data loaded from JSON metadata files.
 #[derive(Clone, Debug, Deserialize)]
 pub struct AtlasMapper {
+    /// Mapping from sprite name to frame bounds within the atlas texture
     pub frames: HashMap<String, MapperFrame>,
 }
 
@@ -72,10 +74,19 @@ impl AtlasTile {
     }
 }
 
+/// High-performance sprite atlas providing fast texture region lookups and rendering.
+///
+/// Combines a single large texture with metadata mapping to enable efficient
+/// sprite rendering without texture switching. Caches color modulation state
+/// to minimize redundant SDL2 calls and supports both named sprite lookups
+/// and optional default color modulation configuration.
 pub struct SpriteAtlas {
+    /// The combined texture containing all sprite frames
     texture: Texture<'static>,
+    /// Mapping from sprite names to their pixel coordinates within the texture
     tiles: HashMap<String, MapperFrame>,
     default_color: Option<Color>,
+    /// Cached color modulation state to avoid redundant SDL2 calls
     last_modulation: Option<Color>,
 }
 
@@ -89,6 +100,12 @@ impl SpriteAtlas {
         }
     }
 
+    /// Retrieves a sprite tile by name from the atlas with fast HashMap lookup.
+    ///
+    /// Returns an `AtlasTile` containing the texture coordinates and dimensions
+    /// for the named sprite, or `None` if the sprite name is not found in the
+    /// atlas. The returned tile can be used for immediate rendering or stored
+    /// for repeated use in animations and entity sprites.
     pub fn get_tile(&self, name: &str) -> Option<AtlasTile> {
         self.tiles.get(name).map(|frame| AtlasTile {
             pos: U16Vec2::new(frame.x, frame.y),