refactor: move DIRECTIONS constant into direction, add as_u8() const fn for array indexing

src/entity/direction.rs

@@ -1,5 +1,6 @@
 use glam::IVec2;
 
+/// The four cardinal directions.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum Direction {
     Up,
@@ -9,7 +10,12 @@ pub enum Direction {
 }
 
 impl Direction {
-    pub fn opposite(&self) -> Direction {
+    /// The four cardinal directions.
+    /// This is just a convenience constant for iterating over the directions.
+    pub const DIRECTIONS: [Direction; 4] = [Direction::Up, Direction::Down, Direction::Left, Direction::Right];
+
+    /// Returns the opposite direction. Constant time.
+    pub const fn opposite(self) -> Direction {
         match self {
             Direction::Up => Direction::Down,
             Direction::Down => Direction::Up,
@@ -18,8 +24,20 @@ impl Direction {
         }
     }
 
-    pub fn as_ivec2(&self) -> IVec2 {
-        (*self).into()
+    /// Returns the direction as an IVec2.
+    pub fn as_ivec2(self) -> IVec2 {
+        self.into()
+    }
+
+    /// Returns the direction as a u8 (0-3). Constant time.
+    /// This is useful for indexing into arrays.
+    pub const fn as_u8(self) -> u8 {
+        match self {
+            Direction::Up => 0,
+            Direction::Down => 1,
+            Direction::Left => 2,
+            Direction::Right => 3,
+        }
     }
 }
 

src/entity/pacman.rs

@@ -1,3 +1,9 @@
+//! Pac-Man entity implementation.
+//!
+//! This module contains the main player character logic, including movement,
+//! animation, and rendering. Pac-Man moves through the game graph using
+//! a traverser and displays directional animated textures.
+
 use glam::{UVec2, Vec2};
 
 use crate::constants::BOARD_PIXEL_OFFSET;
@@ -11,21 +17,34 @@ use sdl2::keyboard::Keycode;
 use sdl2::render::{Canvas, RenderTarget};
 use std::collections::HashMap;
 
+/// Determines if Pac-Man can traverse a given edge.
+///
+/// Pac-Man can only move through edges that allow all entities.
 fn can_pacman_traverse(edge: Edge) -> bool {
     matches!(edge.permissions, EdgePermissions::All)
 }
 
+/// The main player character entity.
+///
+/// Pac-Man moves through the game world using a graph-based navigation system
+/// and displays directional animated sprites based on movement state.
 pub struct Pacman {
+    /// Handles movement through the game graph
     pub traverser: Traverser,
+    /// Manages directional animated textures for different movement states
     texture: DirectionalAnimatedTexture,
 }
 
 impl Pacman {
+    /// Creates a new Pac-Man instance at the specified starting node.
+    ///
+    /// Sets up animated textures for all four directions with moving and stopped states.
+    /// The moving animation cycles through open mouth, closed mouth, and full sprites.
     pub fn new(graph: &Graph, start_node: NodeId, atlas: &SpriteAtlas) -> Self {
         let mut textures = HashMap::new();
         let mut stopped_textures = HashMap::new();
 
-        for &direction in &[Direction::Up, Direction::Down, Direction::Left, Direction::Right] {
+        for direction in Direction::DIRECTIONS {
             let moving_prefix = match direction {
                 Direction::Up => "pacman/up",
                 Direction::Down => "pacman/down",
@@ -56,11 +75,19 @@ impl Pacman {
         }
     }
 
+    /// Updates Pac-Man's position and animation state.
+    ///
+    /// Advances movement through the graph and updates texture animation.
+    /// Movement speed is scaled by 60 FPS and a 1.125 multiplier.
     pub fn tick(&mut self, dt: f32, graph: &Graph) {
         self.traverser.advance(graph, dt * 60.0 * 1.125, &can_pacman_traverse);
         self.texture.tick(dt);
     }
 
+    /// Handles keyboard input to change Pac-Man's direction.
+    ///
+    /// Maps arrow keys to directions and queues the direction change
+    /// for the next valid intersection.
     pub fn handle_key(&mut self, keycode: Keycode) {
         let direction = match keycode {
             Keycode::Up => Some(Direction::Up),
@@ -75,6 +102,9 @@ impl Pacman {
         }
     }
 
+    /// Calculates the current pixel position in the game world.
+    ///
+    /// Interpolates between nodes when moving between them.
     fn get_pixel_pos(&self, graph: &Graph) -> Vec2 {
         match self.traverser.position {
             Position::AtNode(node_id) => graph.get_node(node_id).unwrap().position,
@@ -86,6 +116,10 @@ impl Pacman {
         }
     }
 
+    /// Renders Pac-Man to the canvas.
+    ///
+    /// Calculates screen position, determines if Pac-Man is stopped,
+    /// and renders the appropriate directional texture.
     pub fn render<T: RenderTarget>(&self, canvas: &mut Canvas<T>, atlas: &mut SpriteAtlas, graph: &Graph) {
         let pixel_pos = self.get_pixel_pos(graph).round().as_ivec2() + BOARD_PIXEL_OFFSET.as_ivec2();
         let dest = centered_with_size(pixel_pos, UVec2::new(16, 16));

src/map/builder.rs

@@ -1,7 +1,7 @@
 //! Map construction and building functionality.
 
 use crate::constants::{MapTile, BOARD_CELL_SIZE, CELL_SIZE};
-use crate::entity::direction::{Direction, DIRECTIONS};
+use crate::entity::direction::Direction;
 use crate::entity::graph::{EdgePermissions, Graph, Node, NodeId};
 use crate::map::parser::MapTileParser;
 use crate::map::render::MapRenderer;
@@ -75,7 +75,7 @@ impl Map {
 
         // Iterate over the queue, adding nodes to the graph and connecting them to their neighbors
         while let Some(source_position) = queue.pop_front() {
-            for &dir in DIRECTIONS.iter() {
+            for dir in Direction::DIRECTIONS {
                 let new_position = source_position + dir.as_ivec2();
 
                 // Skip if the new position is out of bounds
@@ -121,7 +121,7 @@ impl Map {
 
         // While most nodes are already connected to their neighbors, some may not be, so we need to connect them
         for (grid_pos, &node_id) in &grid_to_node {
-            for dir in DIRECTIONS {
+            for dir in Direction::DIRECTIONS {
                 // If the node doesn't have an edge in this direction, look for a neighbor in that direction
                 if graph.adjacency_list[node_id].get(dir).is_none() {
                     let neighbor = grid_pos + dir.as_ivec2();