Initial work on rollback and refactor

src/netcode/mod.rs

@@ -0,0 +1,31 @@
+//! Rollback networking: session setup and the engine-level rollback
+//! registrations. Gameplay components are registered by the plugin that owns
+//! them, not here.
+
+use bevy::prelude::*;
+use bevy_egui::EguiPrimaryContextPass;
+use bevy_ggrs::prelude::*;
+
+pub mod debug;
+pub mod session;
+
+/// The GGRS configuration for this game — notably, what a frame of input is.
+pub type GGRSCfg = GgrsConfig<crate::input::FighterInputFrame>;
+
+#[derive(Default)]
+pub struct FighterNetcodePlugin;
+
+impl Plugin for FighterNetcodePlugin {
+    fn build(&self, app: &mut App) {
+        let plugin = GgrsPlugin::<GGRSCfg>::default();
+        app.add_plugins(plugin)
+            .add_systems(Startup, session::netcode_setup)
+            // Engine-level components that every rolled-back entity may carry.
+            // Gameplay components are registered by the plugin that owns them.
+            .rollback_component_with_clone::<Transform>()
+            .rollback_component_with_clone::<Name>()
+            .add_systems(EguiPrimaryContextPass, debug::network_debug)
+            .add_systems(Update, session::print_events_system)
+            .insert_resource(RollbackFrameRate(60));
+    }
+}