test billboard

src/billboards.rs

@@ -0,0 +1,38 @@
+use bevy::prelude::*;
+use bevy_sprite3d::Sprite3dPlugin;
+
+#[derive(Component, Reflect)]
+#[reflect(Component)]
+pub struct Billboard;
+
+pub fn plugin(app: &mut App) {
+    if !app.is_plugin_added::<Sprite3dPlugin>() {
+        app.add_plugins(Sprite3dPlugin);
+    }
+
+    app.register_type::<Billboard>();
+    app.add_systems(Update, face_camera);
+}
+
+fn face_camera(
+    cam_query: Query<&GlobalTransform, With<Camera>>,
+    mut query: Query<
+        (&mut Transform, &Parent, &InheritedVisibility),
+        (With<Billboard>, Without<Camera>),
+    >,
+    parent_transform: Query<&GlobalTransform>,
+) {
+    let cam_transform = cam_query.single();
+    for (mut transform, parent, visible) in query.iter_mut() {
+        if !matches!(*visible, InheritedVisibility::VISIBLE) {
+            continue;
+        }
+
+        let Ok(parent_global) = parent_transform.get(parent.get()) else {
+            continue;
+        };
+
+        let target = cam_transform.reparented_to(parent_global);
+        transform.look_at(target.translation, Vec3::Y);
+    }
+}

src/main.rs

@@ -1,4 +1,5 @@
 mod alien;
+mod billboards;
 mod camera;
 mod cash;
 mod gates;
@@ -72,6 +73,7 @@ fn main() {
     app.add_plugins(gates::plugin);
     app.add_plugins(platforms::plugin);
     app.add_plugins(movables::plugin);
+    app.add_plugins(billboards::plugin);
 
     app.insert_resource(AmbientLight {
         color: Color::WHITE,

src/player.rs

@@ -3,6 +3,7 @@ use std::{f32::consts::PI, time::Duration};
 use crate::{
     DebugVisuals,
     alien::{ALIEN_ASSET_PATH, Animations},
+    billboards::Billboard,
     camera::GameCameraRig,
     cash::{Cash, CashCollectEvent},
     heads_ui::HeadChanged,
@@ -15,6 +16,7 @@ use bevy::{
     window::{CursorGrabMode, PrimaryWindow},
 };
 use bevy_dolly::prelude::Rig;
+use bevy_sprite3d::{Sprite3dBuilder, Sprite3dParams};
 use bevy_tnua::{TnuaUserControlsSystemSet, prelude::*};
 use bevy_tnua_avian3d::TnuaAvian3dSensorShape;
 
@@ -68,6 +70,7 @@ fn spawn(
     asset_server: Res<AssetServer>,
     query: Query<&Transform, With<SpawnPoint>>,
     mut player_spawned: ResMut<PlayerSpawned>,
+    mut sprite_params: Sprite3dParams,
 ) {
     if player_spawned.spawned {
         return;
@@ -81,6 +84,7 @@ fn spawn(
 
     let mesh = asset_server
         .load(GltfAssetLabel::Scene(0).from_asset("models/heads/angry demonstrator.glb"));
+    let selector = asset_server.load("ui/selector.png");
 
     commands
         .spawn((
@@ -109,6 +113,18 @@ fn spawn(
                 .with_rotation(Quat::from_rotation_y(std::f32::consts::PI))
                 .with_scale(Vec3::splat(1.5)),
             SceneRoot(asset_server.load(GltfAssetLabel::Scene(0).from_asset(ALIEN_ASSET_PATH))),
+        ))
+        .with_child((
+            Billboard,
+            Transform::from_translation(Vec3::new(0., 1.5, 0.)),
+            Sprite3dBuilder {
+                image: selector,
+                pixels_per_metre: 40.,
+                alpha_mode: AlphaMode::Blend,
+                unlit: true,
+                ..default()
+            }
+            .bundle(&mut sprite_params),
         ));
 
     commands.spawn((