Merge pull request #20 from cBournhonesque/cb/sync-groups

Simplify entity mapping for prediction/replication

NOTES.md

@@ -12,10 +12,11 @@
     because start tick or end tick are not updated correctly in some edge cases.
 
 
-- add PredictionGroup and InterpolationGroup.
+- add PredictionGroup and InterpolationGroup?
   - on top of ReplicationGroup?
   - or do we just re-use the replication group id (that usually will have a remote entity id) and use it to see the prediction/interpolation group?
   - then we add the prediction group id on the Confirmed or Predicted components?
+  - when we receive a replicated group with ShouldBePredicted, we udpate the replication graph of the prediction group.
 - Then we don't really need the Confirmed/Predicted components anymore, we could just have resources on the Prediction or Interpolation plugin
 - The resource needs:
   - confirmed<->predicted mapping
@@ -25,7 +26,27 @@
   - for each entity, fetch the confirmed/predicted entity
   - do entity mapping if needed
 - users can add their own entities in the prediction group (even if thre )
+- examples:
+  - a shooter, we shoot bullets. the bullets should be in our prediction group?
+    I guess it's not needed if we don't do rollback for those bullets, i.e. we don't give them a Predicted component.
+    Or we could create the bullet, make it part of the entity group; the server will create the bullet a bit later.
+    When the bullet gets replicated on client; we should be able to map the Confirmed to the predicted bullet; so we don't spawn a new predicted.
+    (in practice, for important stuff, we would just wait for the server replication to spawn the entity (instead of spawning it on client and then deleting it if the server version doesn't spawn it?, and for non-important stuff we would just spawn a short-lived entity that is not predicted.)
+  - a character has HasWeapon(Entity), weapon has HasParent(Entity) which forms a cycle. I guess instead of creating this graph of deps,
+    we should just deal with all spawns first separately! Same for prediction, we first do all spawns first
+
 
+
+- TODO: Give an option for rollback to choose how to perform the rollback!
+  - the default option is to snapback instantly to the rollback state.
+  - another option is: snapback to rollback state, perform rollback, then tell the user the previous predicted state and the new predicted state.
+    for example they could choose to lerp over several frames from the [old to new] (i.e correct only 10% of the way).
+    this would cause many consecutive rollback frames, but smoother corrections.
+  - register a component RollbackResult<C> {
+      // use option because the component could have gotten removed
+      old: Option<C>, 
+      new: Option<C>,
+    }
 
 
 - DEBUGGING REPLICATION BOX:

examples/replication_groups/client.rs

@@ -278,7 +278,7 @@ pub(crate) fn interpolate(
                 assert_eq!(tail_status.current, parent_status.current);
                 *tail = tail_start_value.clone();
                 *parent_position = pos_start.clone();
-                info!(
+                debug!(
                     ?tail,
                     ?parent_position,
                     "after interpolation; CURRENT = START"
@@ -296,7 +296,7 @@ pub(crate) fn interpolate(
                     assert_eq!(tail_status.current, parent_status.current);
                     *tail = tail_end_value.clone();
                     *parent_position = pos_end.clone();
-                    info!(
+                    debug!(
                         ?tail,
                         ?parent_position,
                         "after interpolation; CURRENT = END"
@@ -324,13 +324,13 @@ pub(crate) fn interpolate(
                             != tail_start_value.0.front().unwrap().0
                         {
                             tail.0.push_front(tail_end_value.0.front().unwrap().clone());
-                            info!("ADD POINT");
+                            debug!("ADD POINT");
                         }
                         // the path is straight! just move the head and adjust the tail
                         *parent_position =
                             PlayerPosition::lerp(pos_start.clone(), pos_end.clone(), t);
                         tail.shorten_back(parent_position.0, tail_length.0);
-                        info!(
+                        debug!(
                             ?tail,
                             ?parent_position,
                             "after interpolation; FIRST SEGMENT"
@@ -371,7 +371,7 @@ pub(crate) fn interpolate(
                     // now move the head by `pos_distance_to_do` while remaining on the tail path
                     for i in (0..segment_idx).rev() {
                         let dist = segment_length(parent_position.0, tail_end_value.0[i].0);
-                        info!(
+                        debug!(
                             ?i,
                             ?dist,
                             ?pos_distance_to_do,
@@ -380,7 +380,7 @@ pub(crate) fn interpolate(
                             "in other segments"
                         );
                         if pos_distance_to_do < 1000.0 * f32::EPSILON {
-                            info!(?tail, ?parent_position, "after interpolation; ON POINT");
+                            debug!(?tail, ?parent_position, "after interpolation; ON POINT");
                             // no need to change anything
                             continue 'outer;
                         }
@@ -406,7 +406,7 @@ pub(crate) fn interpolate(
                                 .1
                                 .get_tail(tail_end_value.0[i].0, dist - pos_distance_to_do);
                             tail.shorten_back(parent_position.0, tail_length.0);
-                            info!(?tail, ?parent_position, "after interpolation; ELSE");
+                            debug!(?tail, ?parent_position, "after interpolation; ELSE");
                             continue 'outer;
                         }
                     }
@@ -419,7 +419,7 @@ pub(crate) fn interpolate(
                         .1
                         .get_tail(pos_end.0, dist - pos_distance_to_do);
                     tail.shorten_back(parent_position.0, tail_length.0);
-                    info!(?tail, ?parent_position, "after interpolation; ELSE FIRST");
+                    debug!(?tail, ?parent_position, "after interpolation; ELSE FIRST");
                 }
             }
         }

examples/replication_groups/shared.rs

@@ -28,14 +28,10 @@ pub struct SharedPlugin;
 
 impl Plugin for SharedPlugin {
     fn build(&self, app: &mut App) {
-        app.add_plugins(WorldInspectorPlugin::new());
         app.add_systems(Update, draw_snakes);
     }
 }
 
-// head
-// snake
-
 // This system defines how we update the player's positions when we receive an input
 pub(crate) fn shared_movement_behaviour(position: &mut PlayerPosition, input: &Inputs) {
     const MOVE_SPEED: f32 = 10.0;
@@ -121,13 +117,13 @@ pub(crate) fn draw_snakes(
         if position.0.x != points.0.front().unwrap().0.x
             && position.0.y != points.0.front().unwrap().0.y
         {
-            info!("DIAGONAL");
+            debug!("DIAGONAL");
         }
         // draw the rest of the lines
         for (start, end) in points.0.iter().zip(points.0.iter().skip(1)) {
             gizmos.line_2d(start.0, end.0, color.0);
             if start.0.x != end.0.x && start.0.y != end.0.y {
-                info!("DIAGONAL");
+                debug!("DIAGONAL");
             }
         }
     }

lightyear/src/channel/builder.rs

@@ -1,7 +1,8 @@
 //! This module contains the [`Channel`] trait
-use lightyear_macros::ChannelInternal;
 use std::time::Duration;
 
+use lightyear_macros::ChannelInternal;
+
 use crate::channel::receivers::ordered_reliable::OrderedReliableReceiver;
 use crate::channel::receivers::sequenced_reliable::SequencedReliableReceiver;
 use crate::channel::receivers::sequenced_unreliable::SequencedUnreliableReceiver;

lightyear/src/channel/receivers/mod.rs

@@ -1,8 +1,8 @@
-use enum_dispatch::enum_dispatch;
-
-use crate::packet::message::{MessageContainer, SingleData};
+use crate::packet::message::MessageContainer;
+use crate::packet::message::{FragmentData, SingleData};
 use crate::shared::tick_manager::TickManager;
 use crate::shared::time_manager::TimeManager;
+use enum_dispatch::enum_dispatch;
 
 /// Utilities to receive a Message from multiple fragment packets
 pub(crate) mod fragment_receiver;

lightyear/src/channel/senders/fragment_ack_receiver.rs

@@ -1,11 +1,8 @@
-use bevy::utils::HashMap;
-
 use anyhow::Result;
-use bytes::Bytes;
+use bevy::utils::HashMap;
 use tracing::{error, trace};
 
-use crate::packet::message::{FragmentData, FragmentIndex, MessageAck, MessageId, SingleData};
-use crate::packet::packet::FRAGMENT_SIZE;
+use crate::packet::message::{FragmentIndex, MessageId};
 use crate::shared::time_manager::WrappedTime;
 
 /// `FragmentReceiver` is used to reconstruct fragmented messages
@@ -103,8 +100,6 @@ impl FragmentAckTracker {
 
 #[cfg(test)]
 mod tests {
-    use crate::channel::senders::fragment_sender::FragmentSender;
-
     use super::*;
 
     #[test]

lightyear/src/channel/senders/mod.rs

@@ -1,13 +1,11 @@
-use std::collections::VecDeque;
-
-use bytes::Bytes;
-use crossbeam_channel::Receiver;
-use enum_dispatch::enum_dispatch;
-
 use crate::packet::message::{FragmentData, MessageAck, MessageId, SingleData};
 use crate::shared::ping::manager::PingManager;
 use crate::shared::tick_manager::TickManager;
 use crate::shared::time_manager::TimeManager;
+use bytes::Bytes;
+use crossbeam_channel::Receiver;
+use enum_dispatch::enum_dispatch;
+use std::collections::VecDeque;
 
 pub(crate) mod fragment_ack_receiver;
 pub(crate) mod fragment_sender;

lightyear/src/channel/senders/reliable.rs

@@ -4,7 +4,7 @@ use std::time::Duration;
 
 use bytes::Bytes;
 use crossbeam_channel::Receiver;
-use tracing::{info, trace};
+use tracing::trace;
 
 use crate::channel::builder::ReliableSettings;
 use crate::channel::senders::fragment_sender::FragmentSender;

lightyear/src/channel/senders/unordered_unreliable_with_acks.rs

@@ -1,16 +1,15 @@
-use bevy::utils::HashMap;
 use std::collections::VecDeque;
 
 use bytes::Bytes;
+use crossbeam_channel::{Receiver, Sender};
 
 use crate::channel::senders::fragment_ack_receiver::FragmentAckReceiver;
 use crate::channel::senders::fragment_sender::FragmentSender;
 use crate::channel::senders::ChannelSend;
-use crate::packet::message::{FragmentData, FragmentIndex, MessageAck, MessageId, SingleData};
+use crate::packet::message::{FragmentData, MessageAck, MessageId, SingleData};
 use crate::shared::ping::manager::PingManager;
 use crate::shared::tick_manager::TickManager;
 use crate::shared::time_manager::{TimeManager, WrappedTime};
-use crossbeam_channel::{Receiver, Sender};
 
 const DISCARD_AFTER: chrono::Duration = chrono::Duration::milliseconds(3000);
 
@@ -130,10 +129,9 @@ impl ChannelSend for UnorderedUnreliableWithAcksSender {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-    use crate::channel::senders::fragment_ack_receiver::FragmentAckTracker;
     use crate::packet::packet::FRAGMENT_SIZE;
-    use crossbeam_channel::TryRecvError;
+
+    use super::*;
 
     #[test]
     fn test_receive_ack() {

lightyear/src/client/components.rs

@@ -1,11 +1,11 @@
 /*!
 Defines components that are used for the client-side prediction and interpolation
 */
+use std::fmt::Debug;
 
-use crate::prelude::{Named, TypeNamed};
-use bevy::ecs::component::TableStorage;
 use bevy::prelude::{Component, Entity};
-use std::fmt::{Debug, Formatter};
+
+use crate::prelude::{MapEntities, Named};
 
 /// Marks an entity that contains the server-updates that are received from the Server
 /// (this entity is a copy of Predicted that is RTT ticks behind)
@@ -15,7 +15,7 @@ pub struct Confirmed {
     pub interpolated: Option<Entity>,
 }
 
-pub trait SyncComponent: Component + Clone + PartialEq + Named {
+pub trait SyncComponent: Component + Clone + PartialEq + Named + for<'a> MapEntities<'a> {
     fn mode() -> ComponentSyncMode;
 }
 

lightyear/src/client/config.rs

@@ -6,8 +6,6 @@ use crate::client::interpolation::plugin::InterpolationConfig;
 use crate::client::prediction::plugin::PredictionConfig;
 use crate::client::sync::SyncConfig;
 use crate::shared::config::SharedConfig;
-use crate::transport::io::IoConfig;
-
 use crate::shared::ping::manager::PingConfig;
 
 #[derive(Clone)]

lightyear/src/client/connection.rs

@@ -3,20 +3,14 @@
 use std::time::Duration;
 
 use anyhow::Result;
-use bevy::prelude::World;
-use tracing::{debug, info, trace};
+use tracing::{debug, trace};
 
-use crate::channel::builder::PingChannel;
 use crate::client::sync::SyncConfig;
-use crate::connection::events::ConnectionEvents;
-use crate::connection::message::ProtocolMessage;
 use crate::inputs::input_buffer::InputBuffer;
-use crate::packet::packet_manager::Payload;
-use crate::protocol::channel::{ChannelKind, ChannelRegistry};
+use crate::protocol::channel::ChannelRegistry;
 use crate::protocol::Protocol;
 use crate::serialize::reader::ReadBuffer;
-use crate::shared::ping::manager::{PingConfig, PingManager};
-use crate::shared::ping::message::SyncMessage;
+use crate::shared::ping::manager::PingConfig;
 use crate::shared::tick_manager::Tick;
 use crate::shared::tick_manager::TickManager;
 use crate::shared::time_manager::TimeManager;

lightyear/src/client/events.rs

@@ -1,7 +1,6 @@
 //! Wrapper around [`ConnectionEvents`] that adds client-specific functionality
 //!
 use crate::connection::events::ConnectionEvents;
-use crate::prelude::Tick;
 use crate::protocol::Protocol;
 
 pub struct ClientEvents<P: Protocol> {

lightyear/src/client/input.rs

@@ -1,5 +1,4 @@
 //! Handles client-generated inputs
-use anyhow::Context;
 use bevy::prelude::{
     not, App, EventReader, EventWriter, FixedUpdate, IntoSystemConfigs, IntoSystemSetConfigs,
     Plugin, PostUpdate, Res, ResMut, SystemSet,

lightyear/src/client/interpolation/despawn.rs

@@ -1,10 +1,9 @@
-use std::collections::HashMap;
-
-use bevy::prelude::{Commands, Entity, EventReader, Query, RemovedComponents, ResMut, Resource};
+use bevy::prelude::{Commands, EventReader, Query, RemovedComponents, ResMut};
 
 use crate::client::components::{Confirmed, SyncComponent};
 use crate::client::interpolation::interpolate::InterpolateStatus;
 use crate::client::interpolation::interpolation_history::ConfirmedHistory;
+use crate::client::interpolation::resource::InterpolationManager;
 use crate::shared::events::ComponentRemoveEvent;
 
 // Despawn logic:
@@ -17,13 +16,6 @@ use crate::shared::events::ComponentRemoveEvent;
 // - TODO: despawning another client entity as a consequence from prediction, but we want to roll that back:
 //   - maybe we don't do it, and we wait until we are sure (confirmed despawn) before actually despawning the entity
 
-#[derive(Resource, Default)]
-/// Mapping from confirmed entities to interpolated entities
-/// Needed to despawn interpolated entities when the confirmed entity gets despawned
-pub struct InterpolationMapping {
-    pub confirmed_to_interpolated: HashMap<Entity, Entity>,
-}
-
 /// Remove the component from interpolated entities when it gets removed from confirmed
 pub(crate) fn removed_components<C: SyncComponent>(
     mut commands: Commands,
@@ -46,12 +38,16 @@ pub(crate) fn removed_components<C: SyncComponent>(
 /// Despawn interpolated entities when the confirmed entity gets despawned
 /// TODO: we should despawn interpolated only when it reaches the latest confirmed snapshot?
 pub(crate) fn despawn_interpolated(
+    mut manager: ResMut<InterpolationManager>,
     mut commands: Commands,
-    mut mapping: ResMut<InterpolationMapping>,
     mut query: RemovedComponents<Confirmed>,
 ) {
-    for entity in query.read() {
-        if let Some(interpolated) = mapping.confirmed_to_interpolated.remove(&entity) {
+    for confirmed_entity in query.read() {
+        if let Some(interpolated) = manager
+            .interpolated_entity_map
+            .remote_to_interpolated
+            .remove(&confirmed_entity)
+        {
             if let Some(mut entity_mut) = commands.get_entity(interpolated) {
                 entity_mut.despawn();
             }

lightyear/src/client/interpolation/interpolate.rs

@@ -1,5 +1,5 @@
 use bevy::prelude::{Component, Query, ResMut};
-use tracing::{info, trace, warn};
+use tracing::trace;
 
 use crate::client::components::{ComponentSyncMode, SyncComponent};
 use crate::client::interpolation::interpolation_history::ConfirmedHistory;