bevy_replicon_snap

A Snapshot Interpolation plugin for the networking solution bevy_replicon in the Bevy game engine.

This library is a very rough proof of concept and not meant to be used in productive games

Features

• Basic but customizable snapshot interpolation for replicated components
• Client-Side prediction:
  • Owner predicted: Owner client of the entity predicts, other clients interpolate

In the examples you can find a clone of the Simple Box example of bevy_replicon, in 3 versions: no interpolation or prediction, interpolated, predicted. I recommend to look at the diffs between those examples to gain a better understanding how this plugin works.

Usage

Setup

Add the bevy_replicon plugin and this plugin to your bevy application.

The plugin needs to know the maximum server tick rate to estimate time between snapshots so it needs to be passed in on initialization:

const MAX_TICK_RATE: u16 = 30;

...

.add_plugins((
    DefaultPlugins,
    ReplicationPlugins
        .build()
        .set(ServerPlugin::new(TickPolicy::MaxTickRate(MAX_TICK_RATE))),
    SnapshotInterpolationPlugin {
        max_tick_rate: MAX_TICK_RATE,
    },
))

...

Interpolation

To allow a Component to be interpolated it needs to implement the traits: Interpolate, SnapSerialize and SnapDeserialze.

Fortunately this library provides derive macros for those (Note: Note Interpolate macro only works for types that have a lerp() function right now)

use bevy_replicon_snap_macros::{Interpolate, SnapDeserialize, SnapSerialize};

#[derive(
    Component,
    Deserialize,
    Serialize,
    Interpolate,
    SnapSerialize,
    SnapDeserialize,
    Clone,
)]
struct PlayerPosition(Vec2);

You can also implement Interpolate manually to customize interpolation behaviour for any component.

Next you need to register the component for Interpolation:

app.replicate_interpolated::<PlayerPosition>()

this also registers the component for replication by bevy_replicon.

Last Step is to add the Interpolated Component to any entity that should be interpolated.

commands.spawn((
    PlayerPosition(Vec2::ZERO),
    Replication,
    Interpolated,
    ...
));

Client-Side Prediction

Coming soon.. In the meantime check the "predicted" example!

Alternatives

• bevy_timewarp An awesome predict/rollback library that also has integration with bevy_replicon