From 4e169c1506a6c1f102a061a0797246190c2ce513 Mon Sep 17 00:00:00 2001
From: extrawurst <776816+extrawurst@users.noreply.github.com>
Date: Tue, 9 Dec 2025 22:16:09 +0100
Subject: [PATCH] fix missile trails (#81)

added replicated `SpawnTrail` that acts as a marker and gets picked up by the client to create the visuals.
---
 crates/shared/src/abilities/missile.rs | 41 ++++++---------
 crates/shared/src/character.rs         | 24 +++------
 crates/shared/src/protocol/mod.rs      |  6 ++-
 crates/shared/src/utils/trail.rs       | 71 +++++++++++++++++++++++---
 4 files changed, 91 insertions(+), 51 deletions(-)

diff --git a/crates/shared/src/abilities/missile.rs b/crates/shared/src/abilities/missile.rs
index 0856d8a..65b14c9 100644
--- a/crates/shared/src/abilities/missile.rs
+++ b/crates/shared/src/abilities/missile.rs
@@ -5,7 +5,7 @@ use crate::{
     heads_database::HeadsDatabase,
     physics_layers::GameLayer,
     protocol::{GltfSceneRoot, PlaySound},
-    utils::{global_observer, trail::Trail},
+    utils::{global_observer, trail::SpawnTrail},
 };
 use avian3d::prelude::*;
 use bevy::prelude::*;
@@ -15,7 +15,8 @@ use std::f32::consts::PI;
 const MAX_SHOT_AGES: f32 = 15.;
 const MISSLE_SPEED: f32 = 3.;
 
-#[derive(Component)]
+#[derive(Component, Reflect)]
+#[reflect(Component)]
 struct MissileProjectile {
     time: f32,
     damage: u32,
@@ -40,7 +41,6 @@ fn on_trigger_missile(
     query_transform: Query<&Transform>,
     time: Res<Time>,
     heads_db: Res<HeadsDatabase>,
-    mut gizmo_assets: ResMut<Assets<GizmoAsset>>,
 ) {
     let state = trigger.event().0;
 
@@ -66,6 +66,13 @@ fn on_trigger_missile(
             time: time.elapsed_secs(),
             damage: head.damage,
         },
+        SpawnTrail::new(
+            12,
+            LinearRgba::rgb(1., 0.0, 0.),
+            LinearRgba::rgb(0.9, 0.9, 0.),
+            10.,
+        )
+        .init_with_pos(),
         Collider::capsule_endpoints(0.4, Vec3::new(0., 0., 2.), Vec3::new(0., 0., -2.)),
         CollisionLayers::new(
             LayerMask(GameLayer::Projectile.to_bits()),
@@ -77,29 +84,11 @@ fn on_trigger_missile(
         Visibility::default(),
         transform,
         Replicated,
-        children![
-            (
-                Transform::from_rotation(Quat::from_rotation_x(PI / 2.).inverse()),
-                GltfSceneRoot::Projectile("missile".to_string()),
-                Replicated,
-            ),
-            (
-                Trail::new(
-                    12,
-                    LinearRgba::rgb(1., 0.0, 0.),
-                    LinearRgba::rgb(0.9, 0.9, 0.)
-                )
-                .with_pos(transform.translation),
-                Gizmo {
-                    handle: gizmo_assets.add(GizmoAsset::default()),
-                    line_config: GizmoLineConfig {
-                        width: 10.,
-                        ..default()
-                    },
-                    ..default()
-                },
-            )
-        ],
+        children![(
+            Transform::from_rotation(Quat::from_rotation_x(PI / 2.).inverse()),
+            GltfSceneRoot::Projectile("missile".to_string()),
+            Replicated
+        )],
     ));
 }
 
diff --git a/crates/shared/src/character.rs b/crates/shared/src/character.rs
index 9138b0a..83056e5 100644
--- a/crates/shared/src/character.rs
+++ b/crates/shared/src/character.rs
@@ -3,7 +3,7 @@ use crate::{
     animation::{AnimationController, AnimationFlags},
     heads_database::HeadsDatabase,
     loading_assets::GameAssets,
-    utils::trail::Trail,
+    utils::trail::SpawnTrail,
 };
 use bevy::{
     animation::RepeatAnimation, ecs::system::SystemParam, platform::collections::HashMap,
@@ -125,7 +125,6 @@ fn find_marker_bones(
     mut commands: Commands,
     descendants: Query<&Children>,
     name: Query<&Name>,
-    mut gizmo_assets: ResMut<Assets<GizmoAsset>>,
 ) {
     let entity = trigger.event().entity;
 
@@ -139,21 +138,12 @@ fn find_marker_bones(
             commands.entity(child).insert(ProjectileOrigin);
             origin_found = true;
         } else if name.as_str().starts_with("Trail") {
-            commands.entity(child).insert((
-                Trail::new(
-                    20,
-                    LinearRgba::new(1., 1.0, 1., 0.5),
-                    LinearRgba::new(1., 1., 1., 0.5),
-                ),
-                Gizmo {
-                    handle: gizmo_assets.add(GizmoAsset::default()),
-                    line_config: GizmoLineConfig {
-                        width: 24.,
-                        ..default()
-                    },
-                    ..default()
-                },
-            ));
+            commands.entity(child).insert((SpawnTrail::new(
+                20,
+                LinearRgba::new(1., 1.0, 1., 0.5),
+                LinearRgba::new(1., 1., 1., 0.5),
+                24.,
+            ),));
         }
     }
 
diff --git a/crates/shared/src/protocol/mod.rs b/crates/shared/src/protocol/mod.rs
index e181077..5c570fd 100644
--- a/crates/shared/src/protocol/mod.rs
+++ b/crates/shared/src/protocol/mod.rs
@@ -19,7 +19,10 @@ use crate::{
     platforms::ActivePlatform,
     player::{Player, PlayerBodyMesh},
     tick::GameTick,
-    utils::{auto_rotate::AutoRotation, billboards::Billboard, squish_animation::SquishAnimation},
+    utils::{
+        auto_rotate::AutoRotation, billboards::Billboard, squish_animation::SquishAnimation,
+        trail::SpawnTrail,
+    },
 };
 use avian3d::prelude::{
     AngularInertia, AngularVelocity, CenterOfMass, Collider, ColliderDensity, CollisionLayers,
@@ -96,6 +99,7 @@ pub fn plugin(app: &mut App) {
         .replicate_once::<Npc>()
         .replicate::<SquishAnimation>()
         .replicate_once::<Transform>()
+        .replicate_once::<SpawnTrail>()
         .replicate::<UiActiveHeads>()
         .replicate_as::<Visibility, SerVisibility>();
 
diff --git a/crates/shared/src/utils/trail.rs b/crates/shared/src/utils/trail.rs
index 5a10047..293e4f2 100644
--- a/crates/shared/src/utils/trail.rs
+++ b/crates/shared/src/utils/trail.rs
@@ -1,7 +1,36 @@
 use crate::GameState;
 use bevy::prelude::*;
+use serde::{Deserialize, Serialize};
 
-#[derive(Component)]
+#[derive(Copy, Clone, Component, Reflect, Deserialize, Serialize)]
+#[reflect(Component)]
+pub struct SpawnTrail {
+    pub points: usize,
+    pub col_start: LinearRgba,
+    pub col_end: LinearRgba,
+    pub width: f32,
+    pub init_pos: bool,
+}
+
+impl SpawnTrail {
+    pub fn new(points: usize, col_start: LinearRgba, col_end: LinearRgba, width: f32) -> Self {
+        Self {
+            points,
+            col_start,
+            col_end,
+            width,
+            init_pos: false,
+        }
+    }
+
+    pub fn init_with_pos(mut self) -> Self {
+        self.init_pos = true;
+        self
+    }
+}
+
+#[derive(Component, Reflect)]
+#[reflect(Component)]
 pub struct Trail {
     points: Vec<Vec3>,
     col_start: LinearRgba,
@@ -9,17 +38,19 @@ pub struct Trail {
 }
 
 impl Trail {
-    pub fn new(points: usize, col_start: LinearRgba, col_end: LinearRgba) -> Self {
+    pub fn new(trail: SpawnTrail) -> Self {
         Self {
-            points: Vec::with_capacity(points),
-            col_start,
-            col_end,
+            points: Vec::with_capacity(trail.points),
+            col_start: trail.col_start,
+            col_end: trail.col_end,
         }
     }
 
-    pub fn with_pos(self, pos: Vec3) -> Self {
+    pub fn with_pos(self, pos: Option<Vec3>) -> Self {
         let mut trail = self;
-        trail.add(pos);
+        if let Some(pos) = pos {
+            trail.add(pos);
+        }
         trail
     }
 
@@ -36,6 +67,32 @@ pub fn plugin(app: &mut App) {
         FixedUpdate,
         update_trail.run_if(in_state(GameState::Playing)),
     );
+    #[cfg(feature = "client")]
+    app.add_systems(Update, attach_trail.run_if(in_state(GameState::Playing)));
+}
+
+#[cfg(feature = "client")]
+fn attach_trail(
+    mut commands: Commands,
+    query: Query<(Entity, &Transform, &SpawnTrail), Added<SpawnTrail>>,
+    mut gizmo_assets: ResMut<Assets<GizmoAsset>>,
+) {
+    for (entity, transform, trail) in query.iter() {
+        let width = trail.width;
+        let init_pos = trail.init_pos.then_some(transform.translation);
+        let id = commands
+            .spawn((
+                Trail::new(*trail).with_pos(init_pos),
+                Gizmo {
+                    handle: gizmo_assets.add(GizmoAsset::default()),
+                    line_config: GizmoLineConfig { width, ..default() },
+                    ..default()
+                },
+            ))
+            .id();
+
+        commands.entity(entity).add_child(id);
+    }
 }
 
 fn update_trail(