Upgrade to bevy 0.14

Now need to get the game to actually use the camera...

.cargo/config.toml

@@ -25,10 +25,6 @@ rustflags = [
 
 [target.x86_64-pc-windows-msvc]
 linker = "rust-lld.exe" # Use LLD Linker
-rustflags = [
-  "-Zshare-generics=n",
-  "-Zthreads=0",        # (Nightly) Use improved multithreading with the recommended amount of threads.
-]
 
 [target.wasm32-unknown-unknown]
 runner = "wasm-server-runner"

Cargo.toml

@@ -4,10 +4,23 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-bevy = "0.13"
+bevy = { version = "0.14", features = ["file_watcher", "dynamic_linking"] }
 wee_alloc = "*"
-bevy_mod_picking = "0.18"
+bevy_mod_picking = "0.20"
+thiserror = "1"
+nom = "7"
+# Entity Uuid parsing
+uuid = "1.7.0"
 
+# Enable a small amount of optimization in debug mode
+[profile.dev]
+opt-level = 1
+
+# Enable high optimizations for dependencies (incl. Bevy), but not for our code:
+[profile.dev.package."*"]
+opt-level = 3
+
+# Prioritize binary size for wasm
 [profile.wasm-release]
 inherits = "release"
 opt-level = "z"

assets/README.md

@@ -0,0 +1,18 @@
+# Assets
+
+## Custom Assets
+
+### `.entity` files
+
+Files ending in `.entity` store entity information.
+
+Note: This data is not auto-magically de/serialized by Bevy, we write our own parser using `nom`.
+This custom reading/writing can be found in `src/save.rs`.
+
+All `.entity` files list one component per line.
+Components include:
+* `name <string>` Human readable name for entity
+* `uuid <UUID string>` Globally unique ID for entity
+* `transform translation <f32> <f32> <f32> rotation <f32> <f32> <f32> <f32> scale <f32> <f32> <f32>` 3D Location, Rotation, and Scale for entity
+* `model "<path string>" "<string>"` Declares the entity's 3d model
+* `camera` Marks the entity as a camera

assets/levels/00/entities/camera.entity

@@ -0,0 +1,4 @@
+name camera
+uuid 2e45b7e9-6722-4d50-8ea5-67f25b8b0f62
+transform translation 2.0 2.0 0.0 rotation 0.0 0.0 0.0 1.0 scale 1.0 1.0 1.0
+camera

assets/levels/00/entities/van.entity

@@ -0,0 +1,4 @@
+name van
+uuid 5c270e84-814c-4d51-9ccd-ab79d9e01f1d
+transform translation 0.0 0.0 0.0 rotation 0.0 0.0 0.0 1.0 scale 1.0 1.0 1.0
+model "models/van.glb" "Scene"

src/camera.rs

@@ -0,0 +1,127 @@
+use crate::prelude::*;
+
+/// Menu Plugin; empty struct for Plugin impl
+pub(crate) struct CameraPlugin;
+
+impl Plugin for CameraPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(
+            Update,
+            move_editor_fly_camera.run_if(any_with_component::<FlyCamera>),
+        );
+        app.add_systems(
+            Update,
+            rotate_editor_fly_camera.run_if(any_with_component::<FlyCamera>),
+        );
+    }
+}
+
+#[derive(Component)]
+pub(crate) struct FlyCamera;
+
+/// Fly camera system for moving around like a drone
+/// TODO: Only if key is pressed!
+fn move_editor_fly_camera(
+    mut cameras: Query<(&Camera, &mut Transform), With<FlyCamera>>,
+    windows: Query<&Window>,
+    primary_window: Query<Entity, With<PrimaryWindow>>,
+    keys: Res<ButtonInput<KeyCode>>,
+    time: Res<Time>,
+) {
+    (keys.any_pressed([
+        KeyCode::KeyW,
+        KeyCode::KeyS,
+        KeyCode::KeyA,
+        KeyCode::KeyD,
+        KeyCode::KeyQ,
+        KeyCode::KeyE,
+    ]))
+    .then(|| {
+        // Iterate over all cameras
+        cameras.iter_mut().for_each(|(c, mut t)| {
+            // Determine which window this camera is attached to
+            let target_window = match c.target {
+                RenderTarget::Window(wr) => match wr {
+                    WindowRef::Entity(e) => Some(e),
+                    WindowRef::Primary => Some(primary_window.get_single().unwrap()),
+                },
+                _ => None,
+            };
+            let window = windows.get(target_window.unwrap()).unwrap();
+
+            // If the target window is focused
+            window.focused.then(|| {
+                let move_speed = if keys.pressed(KeyCode::ShiftLeft) {
+                    16.0
+                } else {
+                    4.0
+                };
+                let mut delta = Vec3::ZERO;
+                if keys.pressed(KeyCode::KeyW) {
+                    delta += t.forward() * move_speed * time.delta_seconds()
+                }
+                if keys.pressed(KeyCode::KeyS) {
+                    delta += t.back() * move_speed * time.delta_seconds()
+                }
+                if keys.pressed(KeyCode::KeyA) {
+                    delta += t.left() * move_speed * time.delta_seconds()
+                }
+                if keys.pressed(KeyCode::KeyD) {
+                    delta += t.right() * move_speed * time.delta_seconds()
+                }
+                if keys.pressed(KeyCode::KeyE) {
+                    delta += Vec3::Y * move_speed * time.delta_seconds()
+                }
+                if keys.pressed(KeyCode::KeyQ) {
+                    delta += Vec3::NEG_Y * move_speed * time.delta_seconds()
+                }
+                t.translation += delta;
+            });
+        });
+    });
+}
+
+fn rotate_editor_fly_camera(
+    mut cameras: Query<(&Camera, &mut Transform), With<FlyCamera>>,
+    windows: Query<&Window>,
+    primary_window: Query<Entity, With<PrimaryWindow>>,
+    mouse: Res<ButtonInput<MouseButton>>,
+    mut cursor_events: EventReader<CursorMoved>,
+) {
+    (!cursor_events.is_empty()).then(|| {
+        // Iterate over all cameras
+        cameras.iter_mut().for_each(|(c, mut t)| {
+            // Determine which window this camera is attached to
+            let target_window = match c.target {
+                RenderTarget::Window(wr) => match wr {
+                    WindowRef::Entity(e) => Some(e),
+                    WindowRef::Primary => Some(primary_window.get_single().unwrap()),
+                },
+                _ => None,
+            };
+            let window = windows.get(target_window.unwrap()).unwrap();
+            if mouse.pressed(MouseButton::Middle) {
+                cursor_events
+                    .read()
+                    .filter_map(|CursorMoved { delta, window, .. }| {
+                        (*window == target_window.unwrap()).then_some(delta)
+                    })
+                    .for_each(|delta| {
+                        if let Some(Vec2 { x, y }) = delta {
+                            // Cribbing from bevy_flycam
+                            // Link: https://github.com/sburris0/bevy_flycam/blob/baffe50e0961ad1491d467fa6ab5551f9f21db8f/src/lib.rs#L145-L151
+                            let (mut yaw, mut pitch, _) = t.rotation.to_euler(EulerRot::YXZ);
+                            let window_scale = window.height().min(window.width());
+                            let sensitivity = 0.00012;
+                            pitch -= (sensitivity * y * window_scale).to_radians();
+                            yaw -= (sensitivity * x * window_scale).to_radians();
+                            t.rotation = Quat::from_axis_angle(Vec3::Y, yaw)
+                                * Quat::from_axis_angle(Vec3::X, pitch);
+                        }
+                    });
+            } else {
+                cursor_events.clear();
+            }
+        });
+    });
+}

src/conditions.rs

@@ -1,5 +1,8 @@
 use bevy::prelude::*;
 
-pub(crate) fn any_component_added<T: Component>(q: Query<Entity, Added<T>>) -> bool {
+///
+/// ECS scheduler active when an entity has a given component added
+///
+pub(crate) fn any_component_added<C: Component>(q: Query<Entity, Added<C>>) -> bool {
     !q.is_empty()
 }

src/editor.rs

@@ -1,3 +1,5 @@
+use bevy::render::primitives::Aabb;
+
 use crate::prelude::*;
 
 pub(crate) struct EditorPlugin;
@@ -12,14 +14,16 @@ impl Plugin for EditorPlugin {
             )
             .add_systems(
                 Update,
-                toggle_editor_window.run_if(state_changed::<EditorState>),
+                (
+                    toggle_editor_window,
+                    toggle_entity_aabb,
+                ).run_if(state_changed::<EditorState>),
             )
             .add_systems(
                 Update,
                 (
                     handle_window_close.run_if(on_event::<WindowCloseRequested>()),
                     plane_gizmos,
-                    // fly_camera,
                 )
                     .run_if(in_state(EditorState::Open)),
             );
@@ -28,7 +32,7 @@ impl Plugin for EditorPlugin {
 
 /// Tracking the open/closed state of the editor
 #[derive(States, Debug, Clone, PartialEq, Eq, Hash, Default, Component)]
-enum EditorState {
+pub(crate) enum EditorState {
     /// The editor is closed => the editor window is disabled
     #[default]
     Closed,
@@ -78,6 +82,7 @@ fn init_editor(mut commands: Commands) {
     let editor_camera = commands
         .spawn((
             EditorTag,
+            FlyCamera,
             Camera3dBundle {
                 camera: Camera {
                     target: RenderTarget::Window(WindowRef::Entity(editor_window)),
@@ -102,7 +107,7 @@ fn init_editor(mut commands: Commands) {
                 TextBundle::from_section(
                     "Welcome to the editor",
                     TextStyle {
-                        color: Color::WHITE,
+                        color: WHITE.into(),
                         ..default()
                     },
                 ),
@@ -162,25 +167,61 @@ fn plane_gizmos(mut gizmos: Gizmos) {
     let r = 20.0;
     let start = -r as i8;
     let end = r as i8;
-    (start..=end).into_iter().for_each(|n| {
+    (start..=end).for_each(|n| {
         {
             let offset = Vec3::Z * (n as f32);
-            gizmos.line(Vec3::NEG_X * r + offset, Vec3::X * r + offset, Color::GRAY);
+            gizmos.line(Vec3::NEG_X * r + offset, Vec3::X * r + offset, GRAY);
         }
         {
             let offset = Vec3::X * (n as f32);
-            gizmos.line(Vec3::NEG_Z * r + offset, Vec3::Z * r + offset, Color::GRAY);
+            gizmos.line(Vec3::NEG_Z * r + offset, Vec3::Z * r + offset, GRAY);
         }
     });
 
     // World origin arrows
     {
-        gizmos.arrow(Vec3::ZERO, Vec3::X, Color::RED);
-        gizmos.arrow(Vec3::ZERO, Vec3::Y, Color::DARK_GREEN);
-        gizmos.arrow(Vec3::ZERO, Vec3::Z, Color::BLUE);
+        gizmos.arrow(Vec3::ZERO, Vec3::X, RED);
+        gizmos.arrow(Vec3::ZERO, Vec3::Y, DARK_GREEN);
+        gizmos.arrow(Vec3::ZERO, Vec3::Z, BLUE);
+    }
+}
+
+fn toggle_entity_aabb(
+    state: Res<State<EditorState>>,
+    query: Query<Entity, With<Handle<SaveEntity>>>,
+    children: Query<&Children>,
+    aabbs: Query<(Entity, &Aabb)>,
+    mut commands: Commands,
+) {
+    let add_component = match state.get() {
+        EditorState::Open => true,
+        EditorState::Closed => false,
+    };
+    query.iter().for_each(|root| {
+        if add_component {
+            commands.entity(root).insert(ShowAabbGizmo { ..default() });
+        } else {
+            commands.entity(root).remove::<ShowAabbGizmo>();
+        }
+
+        let mut child_has_bounding_box = false;
+        for child in children.iter_descendants(root) {
+            if add_component {
+                commands.entity(child).insert(ShowAabbGizmo { ..default() });
+            } else {
+                commands.entity(child).remove::<ShowAabbGizmo>();
+            }
+            if aabbs.contains(child) {
+                commands.entity(child).insert(Aabb { center: Vec3A::ZERO, half_extents: Vec3A::ONE });
+            } else {
+                child_has_bounding_box = true;
             }
         }
 
-fn _fly_camera(mut _camera: Query<&mut Transform, (With<Camera>, With<EditorTag>)>) {
-    todo!()
+        if !aabbs.contains(root) && !child_has_bounding_box {
+            commands.entity(root).insert(Aabb { center: Vec3A::ZERO, half_extents: Vec3A::ONE });
+        } else {
+            commands.entity(root).remove::<Aabb>();
+        }
+    })
 }

src/main.rs

@@ -1,3 +1,5 @@
+/// Camera controller
+pub(crate) mod camera;
 /// ECS scheduling `run_if` conditions
 pub(crate) mod conditions;
 /// Editor: debugging and run-time modifications to the game
@@ -6,6 +8,8 @@ pub(crate) mod editor;
 pub(crate) mod menu;
 /// Helper module containing common imports across the project
 pub(crate) mod prelude;
+/// Level saving/loading logic
+pub(crate) mod save;
 /// Window handling
 pub(crate) mod window;
 
@@ -19,8 +23,10 @@ fn main() {
             exit_condition: bevy::window::ExitCondition::OnPrimaryClosed,
             ..default()
         }))
-        .add_plugins(menu::MenuPlugin)
+        .add_plugins(camera::CameraPlugin)
         .add_plugins(editor::EditorPlugin)
+        .add_plugins(menu::MenuPlugin)
+        .add_plugins(save::SavePlugin)
         .add_plugins(window::WindowPlugin)
         .run();
 }

src/menu.rs

@@ -9,7 +9,7 @@ impl Plugin for MenuPlugin {
 }
 
 fn init_menu(mut commands: Commands) {
-    commands.spawn(Camera3dBundle { ..default() });
+    // commands.spawn(Camera3dBundle { ..default() });
     commands
         .spawn(NodeBundle {
             style: Style {

src/prelude.rs

@@ -1,9 +1,26 @@
-pub(crate) use bevy::app::AppExit;
-pub(crate) use bevy::input::common_conditions::input_just_pressed;
-pub(crate) use bevy::prelude::*;
-pub(crate) use bevy::render::camera::RenderTarget;
-pub(crate) use bevy::window::PrimaryWindow;
-pub(crate) use bevy::window::WindowCloseRequested;
-pub(crate) use bevy::window::WindowRef;
+pub(crate) use bevy::{
+	app::AppExit,
+	asset::{io::Reader, AssetLoader, LoadContext, AsyncReadExt},
+	color::palettes::css::{WHITE, GRAY, RED, DARK_GREEN, BLUE},
+	gltf::Gltf,
+	input::common_conditions::input_just_pressed,
+	math::Vec3A,
+	prelude::*,
+	render::camera::RenderTarget,
+	window::{WindowRef, WindowCloseRequested, PrimaryWindow},
+};
+pub(crate) use nom::{
+	IResult,
+	bytes::complete::{tag, take_until1},
+	character::complete::space1,
+	number::complete::float,
+	sequence::tuple,
+};
+pub(crate) use uuid::Uuid;
+pub(crate) use thiserror::Error;
 
-pub(crate) use crate::conditions::*;
+pub(crate) use crate::{
+	camera::*,
+	conditions::*,
+	save::*,
+};

src/save.rs

@@ -0,0 +1,367 @@
+use crate::prelude::*;
+
+/// Menu Plugin; empty struct for Plugin impl
+pub(crate) struct SavePlugin;
+
+impl Plugin for SavePlugin {
+    fn build(&self, app: &mut App) {
+        app.init_asset::<SaveEntity>()
+            .init_asset_loader::<SaveEntityLoader>()
+            .add_systems(Startup, test_save_entity)
+            .add_systems(
+                Update,
+                check_loaded_entity_assets.run_if(on_event::<AssetEvent<SaveEntity>>()),
+            );
+    }
+}
+
+#[derive(Asset, TypePath, Debug, Default)]
+pub(crate) struct SaveEntity {
+    transform: Option<Transform>,
+    name: Option<Name>,
+    uuid: Option<EntityUuid>,
+    model: Option<(Handle<Gltf>, String)>,
+    // TODO: Option<bool> feels like an antipattern as this is either Some(true) or None and never Some(false).
+    // Either encode more Camera data in this or replace it with Option<()> or just bool.
+    camera: Option<bool>,
+}
+
+impl SaveEntity {
+    fn parse(
+        text: &str,
+        load_context: &mut LoadContext,
+    ) -> Result<SaveEntity, parse::SaveEntityParseError> {
+        let lines = text.split('\n');
+        let mut entity = SaveEntity { ..default() };
+        lines.into_iter().for_each(|line| {
+            if let Ok(name) = parse::parse_save_name(line) {
+                entity.name = Some(name);
+            } else if let Ok(transform) = parse::parse_save_transform(line) {
+                entity.transform = Some(transform);
+            } else if let Ok(uuid) = parse::parse_save_uuid(line) {
+                entity.uuid = Some(EntityUuid(uuid));
+            } else if let Ok((gltf_path, scene_name)) = parse::parse_save_model(line) {
+                let handle = load_context.load(gltf_path);
+                entity.model = Some((handle, scene_name));
+            } else if let Ok(true) = parse::parse_save_camera(line) {
+                entity.camera = Some(true);
+            }
+        });
+        Ok(entity)
+    }
+}
+
+#[derive(Component, Clone, Debug)]
+struct EntityUuid(Uuid);
+
+mod parse {
+    use super::*;
+
+    #[derive(Error, Debug)]
+    pub(crate) enum SaveEntityParseError {
+        #[error("Failed to parse Uuid: {0}")]
+        Uuid(#[from] uuid::Error),
+        #[error("Failed to parse name")]
+        Name,
+        #[error("Failed to parse Transform")]
+        Transform,
+        #[error("Failed to parse Entity")]
+        Nom(nom::Err<nom::error::Error<Box<str>>>),
+    }
+
+    // Convert Nom error to parse error
+    // https://stackoverflow.com/a/77974858/3096574
+    impl From<nom::Err<nom::error::Error<&str>>> for SaveEntityParseError {
+        fn from(err: nom::Err<nom::error::Error<&str>>) -> Self {
+            SaveEntityParseError::Nom(err.map_input(|input| input.into()))
+        }
+    }
+
+    fn parse_word<'a>(w: &'a str) -> impl Fn(&'a str) -> IResult<&'a str, &'a str> {
+        move |i: &'a str| {
+            tag(w)(i)
+        }
+    }
+
+    fn parse_xyz(i: &str) -> IResult<&str, (f32, f32, f32)> {
+        tuple((float, space1, float, space1, float))(i)
+            .map(|(s, (x, _, y, _, z))| (s, (x, y, z)))
+    }
+
+    fn parse_wxyz(i: &str) -> IResult<&str, (f32, f32, f32, f32)> {
+        tuple((
+            float,
+            space1,
+            float,
+            space1,
+            float,
+            space1,
+            float,
+        ))(i)
+        .map(|(s, (w, _, x, _, y, _, z))| (s, (w, x, y, z)))
+    }
+
+    fn parse_string(i: &str) -> IResult<&str, &str> {
+        let (rem, (_, out, _)) = tuple((tag("\""), take_until1("\""), tag("\"")))(i)?;
+        Ok((rem, out))
+    }
+
+    ///
+    /// ```
+    /// let parsed = parse_save_transform("transform translation 1.0 2.0 3.0 rotation 1.0 0.0 0.0 0.0 scale 1.0 1.0 1.0").unwrap();
+    /// let expected = Transform { translation: Vec3::new(1.0, 1.0, 1.0), rotation: Quat::from_xzyw(1.0, 0.0, 0.0, 0.0), scale: Vec3::ONE };
+    ///
+    /// assert_eq!(parsed, expected);
+    /// ```
+    ///
+    pub(crate) fn parse_save_transform(line: &str) -> Result<Transform, SaveEntityParseError> {
+        let (rem, _) = tag("transform")(line)?;
+
+        let mut transform = Transform::default();
+
+        let mut curr = rem.trim_start();
+        for _ in 0..3 {
+            println!("Curr: {:?}", curr);
+            if let Ok((rem, (_, _, (x, y, z)))) = tuple((parse_word("translation"), space1, parse_xyz))(curr.trim_start()) {
+                transform.translation = Vec3::new(x, y, z);
+                curr = rem.trim_start();
+            } else if let Ok((rem, (_, _, (x, y, z, w)))) = tuple((parse_word("rotation"), space1, parse_wxyz))(curr.trim_start()) {
+                transform.rotation = Quat::from_xyzw(x, y, z, w);
+                curr = rem.trim_start();
+            } else if let Ok((rem, (_, _, (x, y, z)))) = tuple((parse_word("scale"), space1, parse_xyz))(curr.trim_start()) {
+                transform.scale = Vec3::new(x, y, z);
+                curr = rem.trim_start();
+            } else {
+                return Err(SaveEntityParseError::Transform);
+            }
+        }
+
+        // Assert there are no trailing characters on the line
+        debug_assert_eq!(curr, "");
+
+        Ok(transform)
+    }
+
+    #[test]
+    fn test_parse_transform() {
+        let line = "transform translation 1.0 2.0 3.0 rotation 0.1 0.2 0.3 1.0 scale 1.1 1.2 1.3";
+        let parsed = parse_save_transform(line).unwrap();
+        let expected = Transform {
+            translation: Vec3::new(1.0, 2.0, 3.0),
+            rotation: Quat::from_xyzw(0.1, 0.2, 0.3, 1.0),
+            scale: Vec3::new(1.1, 1.2, 1.3),
+        };
+
+        assert_eq!(parsed, expected);
+    }
+
+    ///
+    /// ```
+    /// let parsed = parse_save_name("name asfd").unwrap();
+    /// let expected = Name::new("asdf");
+    ///
+    /// assert_eq!(parsed, expected);
+    /// ```
+    ///
+    pub(crate) fn parse_save_name(line: &str) -> Result<Name, SaveEntityParseError> {
+        let (remainder, _) = tag("name")(line)?;
+        let n = remainder.trim().to_string();
+        if n.is_empty() {
+            Err(SaveEntityParseError::Name)
+        } else {
+            let name = Name::new(n);
+            Ok(name)
+        }
+    }
+
+    #[test]
+    fn test_parse_name() {
+        {
+            let line = "name Van";
+            let parsed = parse_save_name(line).unwrap();
+            let expected = Name::new("Van");
+
+            assert_eq!(parsed, expected);
+        }
+        {
+            let line = "name Big Mike";
+            let parsed = parse_save_name(line).unwrap();
+            let expected = Name::new("Big Mike");
+
+            assert_eq!(parsed, expected);
+        }
+    }
+
+    ///
+    /// ```
+    /// let parsed = parse_save_uuid("uuid 339dd18f-761a-4997-b515-ef57f4dc2447").unwrap();
+    /// let expected = Uuid::parse_str("339dd18f-761a-4997-b515-ef57f4dc2447").unwrap();
+    ///
+    /// assert_eq!(parsed, expected);
+    /// ```
+    ///
+    pub(crate) fn parse_save_uuid(line: &str) -> Result<Uuid, SaveEntityParseError> {
+        let (remainder, _) = tag("uuid")(line)?;
+        let uuid = Uuid::try_parse(remainder.trim())?;
+        Ok(uuid)
+    }
+
+    #[test]
+    fn test_parse_uuid() {
+        let line = "uuid 1c16ab9a-5f79-4340-8469-4086f69c64f2";
+        let parsed = parse_save_uuid(line).unwrap();
+        let expected = Uuid::parse_str("1c16ab9a-5f79-4340-8469-4086f69c64f2").unwrap();
+
+        assert_eq!(parsed, expected);
+    }
+
+    pub(crate) fn parse_save_model(line: &str) -> Result<(String, String), SaveEntityParseError> {
+        let (rem, (_, _, gltf_name, _, scene_name)) = tuple((
+            tag("model"),
+            space1,
+            parse_string,
+            space1,
+            parse_string,
+        ))(line)?;
+
+        debug_assert_eq!(rem, "");
+
+        Ok((String::from(gltf_name), String::from(scene_name)))
+    }
+
+    #[test]
+    fn test_parse_model() {
+        let line = "model \"models/foo.glb\" \"My Scene\"";
+        let parsed = parse_save_model(line).unwrap();
+        let expected = (String::from("models/foo.glb"), String::from("My Scene"));
+
+        assert_eq!(parsed, expected);
+    }
+
+    pub(crate) fn parse_save_camera(line: &str) -> Result<bool, SaveEntityParseError> {
+        let (_rem, cam) = tag("camera")(line)?;
+        Ok(!cam.is_empty())
+    }
+
+    #[test]
+    fn test_parse_camera() {
+        {
+            let line = "camera";
+            let parsed = parse_save_camera(line).unwrap();
+            let expected = true;
+            assert_eq!(parsed, expected);
+        }
+        {
+            let line = "notcamera";
+            let parsed = parse_save_camera(line);
+            assert!(parsed.is_err());
+        }
+    }
+}
+
+#[derive(Default)]
+struct SaveEntityLoader;
+
+#[derive(Error, Debug)]
+enum SaveEntityLoaderError {
+    #[error("Could not load asset: {0}")]
+    Io(#[from] std::io::Error),
+    #[error("Could not parse entity: {0}")]
+    Parse(#[from] parse::SaveEntityParseError),
+}
+
+impl AssetLoader for SaveEntityLoader {
+    type Asset = SaveEntity;
+    type Settings = ();
+    type Error = SaveEntityLoaderError;
+
+    async fn load<'a>(
+        &'a self,
+        reader: &'a mut Reader<'_>,
+        _settings: &'a (),
+        load_context: &'a mut LoadContext<'_>,
+    ) -> Result<Self::Asset, Self::Error> {
+        let mut bytes = Vec::new();
+        reader.read_to_end(&mut bytes).await?;
+
+        let s = std::str::from_utf8(bytes.as_slice()).unwrap();
+        let save_entity = SaveEntity::parse(s, load_context)?;
+        Ok(save_entity)
+    }
+
+    fn extensions(&self) -> &[&str] {
+        &["entity"]
+    }
+}
+
+fn test_save_entity(loader: Res<AssetServer>, mut commands: Commands) {
+    let handle: Handle<SaveEntity> = loader.load("levels/00/entities/van.entity");
+    commands.spawn((
+        SpatialBundle { ..default() },
+        handle,
+    ));
+}
+
+fn check_loaded_entity_assets(
+    query: Query<(Entity, &Handle<SaveEntity>)>,
+    mut events: EventReader<AssetEvent<SaveEntity>>,
+    save_entities: Res<Assets<SaveEntity>>,
+    mut commands: Commands,
+    gltfs: Res<Assets<Gltf>>,
+) {
+    events.read().for_each(|event| {
+        if let AssetEvent::LoadedWithDependencies { id } = event {
+            query
+                .iter()
+                .filter(|(_, handle)| handle.id() == *id)
+                .for_each(|(entity, _handle)| {
+                    let saved = save_entities.get(*id).unwrap();
+                    debug!(
+                        "Updating entity {:?} ({:?}) because asset changed",
+                        saved.name, saved.uuid
+                    );
+
+                    let mut e = commands.entity(entity);
+                    // Apply camera
+                    // Should be applied early to avoid clobbering transform
+                    if let Some(is_camera) = &saved.camera {
+                        if *is_camera {
+                            e.insert(Camera3dBundle { ..default() });
+                        }
+                    } else {
+                        e.remove::<(Camera, Camera3d)>();
+                    }
+                    // Apply transform
+                    if let Some(transform) = &saved.transform {
+                        // TODO: Only update if different
+                        e.insert(*transform);
+                    } else {
+                        e.remove::<Transform>();
+                    }
+                    // Apply Name
+                    if let Some(name) = &saved.name {
+                        // TODO: Only update if different
+                        e.insert(name.clone());
+                    } else {
+                        e.remove::<Name>();
+                    }
+                    // Apply Uuid
+                    if let Some(uuid) = &saved.uuid {
+                        // TODO: Only update if different
+                        e.insert(uuid.clone());
+                    } else {
+                        e.remove::<EntityUuid>();
+                    }
+                    // Apply Model 
+                    if let Some((gltf_handle, scene_name)) = &saved.model {
+                        // Find scene and update
+                        let gltf = gltfs.get(gltf_handle).unwrap();
+                        let scene_handle = gltf.named_scenes.get(scene_name.as_str().into()).unwrap();
+                        e.insert(scene_handle.clone());
+                    } else {
+                        e.remove::<Handle<Scene>>();
+                    }
+                });
+        }
+    })
+}

src/window.rs

@@ -36,6 +36,6 @@ fn handle_window_close(
         .filter_map(|WindowCloseRequested { window }| primary.get(*window).ok())
         // If this was the primary window, send an AppExit
         .for_each(|_| {
-            exit.send(AppExit);
+            exit.send(AppExit::Success);
         });
 }