Struct PlayerAreaMap 

pub struct PlayerAreaMap {
    chunks: HashMap<ChunkPos, FxHashSet<i32>>,
    player_chunks: HashMap<i32, FxHashSet<ChunkPos>>,
}

Spatial index for player proximity queries.

Uses packed ChunkPos chunk coordinates as keys for efficient hashing. Thread-safe via scc::HashMap for concurrent access.

The map maintains a dual index:

• chunks: Maps chunk coords to players whose tracking area includes that chunk
• player_chunks: Maps player entity IDs to the set of chunks they’re registered in

This enables O(1) lookup of nearby players and O(tracking area) removal.

Entity IDs are used instead of UUIDs because:

• They are globally unique within a server session (vanilla uses a static atomic counter)
• They are smaller (4 bytes vs 16 bytes) and faster to hash
• PlayerAreaMap only tracks players during a session, not persisted

Fields

chunks: HashMap<ChunkPos, FxHashSet<i32>>

Maps packed chunk coords (ChunkPos) to set of player entity IDs

player_chunks: HashMap<i32, FxHashSet<ChunkPos>>

Maps player entity ID to its current set of tracked chunks (for efficient removal)

Implementations

impl PlayerAreaMap

pub fn new() -> Self

Creates a new player area map.

pub fn on_player_join(&self, player: &Player, view: &PlayerChunkView)

Registers a player at their current position using their chunk view.

pub fn on_player_leave(&self, player: &Arc<Player>)

Removes a player from all tracked chunks.

pub fn remove_by_entity_id(&self, entity_id: i32)

Removes a player from all tracked chunks by entity ID.

This is useful when you don’t have an Arc<Player> reference, such as during respawn cleanup.

pub fn on_player_view_change( &self, entity_id: i32, added_chunks: &[ChunkPos], removed_chunks: &[ChunkPos], )

Updates a player’s tracked chunks using pre-computed view differences.

Call this after computing the difference via PlayerChunkView::difference().

pub fn get_tracking_players(&self, chunk: ChunkPos) -> Vec<i32>

Gets all players tracking the given chunk.

pub fn len(&self) -> usize

Returns the number of tracked players.

pub fn is_empty(&self) -> bool

Returns true if no players are tracked.

fn add_to_chunk(&self, chunk: ChunkPos, entity_id: i32)

fn remove_from_chunk(&self, chunk: ChunkPos, entity_id: i32)

Trait Implementations

impl Default for PlayerAreaMap

fn default() -> Self

Returns the “default value” for a type.