From cdca700297b3bcd6b1f386343b4529713aedf5d7 Mon Sep 17 00:00:00 2001
From: Imbris <imbrisf@gmail.com>
Date: Mon, 5 Jun 2023 18:23:07 -0400
Subject: [PATCH] Properly check conditions for when the client's physics
 components should be synced

---
 client/src/lib.rs             |  7 ++++++
 server/src/state_ext.rs       |  2 +-
 server/src/sys/entity_sync.rs | 45 +++++++++++++++++++++++++----------
 3 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/client/src/lib.rs b/client/src/lib.rs
index c19d73529b..5ccb65ff65 100644
--- a/client/src/lib.rs
+++ b/client/src/lib.rs
@@ -2257,10 +2257,17 @@ impl Client {
                     .apply_entity_sync_package(entity_sync_package, uid);
             },
             ServerGeneral::CompSync(comp_sync_package, force_counter) => {
+                // TODO: Test with and without sync_me = true commented out to see if results are
+                // as expected. (client shouldn't normally receive updates if client physics is
+                // enabled)
+                let b = self.position();
                 self.force_update_counter = force_counter;
                 self.state
                     .ecs_mut()
                     .apply_comp_sync_package(comp_sync_package);
+                if b != self.position() {
+                    println!("{b:?}");
+                }
             },
             ServerGeneral::CreateEntity(entity_package) => {
                 self.state.ecs_mut().apply_entity_package(entity_package);
diff --git a/server/src/state_ext.rs b/server/src/state_ext.rs
index eedded76f5..30746a90c3 100644
--- a/server/src/state_ext.rs
+++ b/server/src/state_ext.rs
@@ -709,7 +709,7 @@ impl StateExt for State {
                         self.ecs()
                             .write_resource::<IdMaps>()
                             .add_character(id, entity);
-                        presence.sync_me = true;
+                        //presence.sync_me = true;
                         Ok(())
                     } else {
                         Err("PresenceKind is not LoadingCharacter")
diff --git a/server/src/sys/entity_sync.rs b/server/src/sys/entity_sync.rs
index e53c5d9aae..898731efd8 100644
--- a/server/src/sys/entity_sync.rs
+++ b/server/src/sys/entity_sync.rs
@@ -4,6 +4,8 @@ use common::{
     calendar::Calendar,
     comp::{Collider, ForceUpdate, InventoryUpdate, Last, Ori, Player, Pos, Presence, Vel},
     event::EventBus,
+    link::Is,
+    mounting::Rider,
     outcome::Outcome,
     region::{Event as RegionEvent, RegionMap},
     resources::{PlayerPhysicsSettings, Time, TimeOfDay, TimeScale},
@@ -247,18 +249,13 @@ impl<'a> System<'a> for Sys {
                     {
                         // Decide how regularly to send physics updates.
                         let send_now = if client_entity == &entity {
-                            let player_physics_setting = players
-                                .get(entity)
-                                .and_then(|p| {
-                                    player_physics_settings.settings.get(&p.uuid()).copied()
-                                })
-                                .unwrap_or_default();
-                            // Don't send client physics updates about itself unless force update is
-                            // set or the client is subject to
-                            // server-authoritative physics
-                            force_updates.get(entity).map_or(false, |f| f.is_forced())
-                                || player_physics_setting.server_authoritative()
-                                || is_rider.get(entity).is_some()
+                            should_sync_client_physics(
+                                entity,
+                                &player_physics_settings,
+                                &players,
+                                &force_updates,
+                                is_rider,
+                            )
                         } else if matches!(collider, Some(Collider::Voxel { .. })) {
                             // Things with a voxel collider (airships, etc.) need to have very
                             // stable physics so we always send updated
@@ -338,7 +335,8 @@ impl<'a> System<'a> for Sys {
             );
 
             if include_all_comps && let Some(&pos) = maybe_pos {
-                add_physics_components(true, &mut comp_sync_package, uid, pos, last_pos, ori, vel);
+                let send_now = should_sync_client_physics(entity, &player_physics_settings, &players, &force_updates, is_rider);
+                add_physics_components(send_now, &mut comp_sync_package, uid, pos, last_pos, ori, vel);
             }
 
             if !comp_sync_package.is_empty() {
@@ -448,6 +446,27 @@ impl<'a> System<'a> for Sys {
     }
 }
 
+/// Determines whether a client should receive an update about its own physics
+/// components.
+fn should_sync_client_physics(
+    entity: specs::Entity,
+    player_physics_settings: &PlayerPhysicsSettings,
+    players: &ReadStorage<'_, Player>,
+    force_updates: &WriteStorage<'_, ForceUpdate>,
+    is_rider: &ReadStorage<'_, Is<Rider>>,
+) -> bool {
+    let player_physics_setting = players
+        .get(entity)
+        .and_then(|p| player_physics_settings.settings.get(&p.uuid()).copied())
+        .unwrap_or_default();
+    // Don't send client physics updates about itself unless force update is
+    // set or the client is subject to
+    // server-authoritative physics
+    force_updates.get(entity).map_or(false, |f| f.is_forced())
+        || player_physics_setting.server_authoritative()
+        || is_rider.contains(entity)
+}
+
 /// Adds physics components if `send_now` is true or `Option<Last<T>>` is
 /// `None`.
 ///