From e13d0ffe7a8bdcac943dbf5d5ae988135408b2c4 Mon Sep 17 00:00:00 2001
From: Daniel Huth <4455258+Agreon@users.noreply.github.com>
Date: Sun, 9 Oct 2022 11:12:30 +1300
Subject: [PATCH] Skip spawn of non visible player characters (#100)

* Skip spawn of non visible player characters
* Don't spawn player if player list is `None`

Co-authored-by: Ryan <ryanj00a@gmail.com>
---
 src/client.rs      | 29 ++++++++++++++++++++---------
 src/player_list.rs | 14 ++++++++++++++
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/src/client.rs b/src/client.rs
index cbd4308..c64b17e 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -188,8 +188,8 @@ pub struct Client<C: Config> {
     username: String,
     textures: Option<SignedPlayerTextures>,
     world: WorldId,
+    player_list: Option<PlayerListId>,
     old_player_list: Option<PlayerListId>,
-    new_player_list: Option<PlayerListId>,
     position: Vec3<f64>,
     old_position: Vec3<f64>,
     /// Measured in m/s.
@@ -271,7 +271,7 @@ impl<C: Config> Client<C> {
             textures: ncd.textures,
             world: WorldId::default(),
             old_player_list: None,
-            new_player_list: None,
+            player_list: None,
             position: Vec3::default(),
             old_position: Vec3::default(),
             velocity: Vec3::default(),
@@ -334,14 +334,14 @@ impl<C: Config> Client<C> {
 
     /// Gets the player list this client sees.
     pub fn player_list(&self) -> Option<&PlayerListId> {
-        self.new_player_list.as_ref()
+        self.player_list.as_ref()
     }
 
     /// Sets the player list this client sees.
     ///
     /// The previous player list ID is returned.
     pub fn set_player_list(&mut self, id: impl Into<Option<PlayerListId>>) -> Option<PlayerListId> {
-        mem::replace(&mut self.new_player_list, id.into())
+        mem::replace(&mut self.player_list, id.into())
     }
 
     /// Sets if this client sees the world as superflat. Superflat worlds have
@@ -1035,7 +1035,7 @@ impl<C: Config> Client<C> {
         if self.created_this_tick() {
             self.bits.set_spawn(false);
 
-            if let Some(id) = &self.new_player_list {
+            if let Some(id) = &self.player_list {
                 player_lists
                     .get(id)
                     .initial_packets(|p| send_packet(&mut self.send, p));
@@ -1118,7 +1118,7 @@ impl<C: Config> Client<C> {
             }
 
             // If the player list was changed...
-            if self.old_player_list != self.new_player_list {
+            if self.old_player_list != self.player_list {
                 // Delete existing entries from old player list.
                 if let Some(id) = &self.old_player_list {
                     player_lists
@@ -1127,14 +1127,14 @@ impl<C: Config> Client<C> {
                 }
 
                 // Get initial packets for new player list.
-                if let Some(id) = &self.new_player_list {
+                if let Some(id) = &self.player_list {
                     player_lists
                         .get(id)
                         .initial_packets(|p| send_packet(&mut self.send, p));
                 }
 
-                self.old_player_list = self.new_player_list.clone();
-            } else if let Some(id) = &self.new_player_list {
+                self.old_player_list = self.player_list.clone();
+            } else if let Some(id) = &self.player_list {
                 // Update current player list.
                 player_lists
                     .get(id)
@@ -1452,6 +1452,17 @@ impl<C: Config> Client<C> {
                 let entity = entities
                     .get(id)
                     .expect("entity IDs in spatial index should be valid at this point");
+
+                // Skip spawning players not in the player list because they would be invisible
+                // otherwise.
+                if entity.kind() == EntityKind::Player {
+                    if let Some(list_id) = &self.player_list {
+                        player_lists.get(list_id).entry(entity.uuid())?;
+                    } else {
+                        return None;
+                    }
+                }
+
                 if entity.kind() != EntityKind::Marker
                     && entity.uuid() != self.uuid
                     && self.loaded_entities.insert(id)
diff --git a/src/player_list.rs b/src/player_list.rs
index f116004..8415006 100644
--- a/src/player_list.rs
+++ b/src/player_list.rs
@@ -222,6 +222,20 @@ impl<C: Config> PlayerList<C> {
         }
     }
 
+    /// Returns a reference to the entry with the given UUID.
+    ///
+    /// If the entry does not exist, `None` is returned.
+    pub fn entry(&self, uuid: Uuid) -> Option<&PlayerListEntry> {
+        self.entries.get(&uuid)
+    }
+
+    /// Returns a mutable reference to the entry with the given UUID.
+    ///
+    /// If the entry does not exist, `None` is returned.
+    pub fn entry_mut(&mut self, uuid: Uuid) -> Option<&mut PlayerListEntry> {
+        self.entries.get_mut(&uuid)
+    }
+
     /// Returns an iterator over all entries in an unspecified order.
     pub fn entries(&self) -> impl Iterator<Item = (Uuid, &PlayerListEntry)> + '_ {
         self.entries.iter().map(|(k, v)| (*k, v))