Serialization

Cargo.toml

@@ -10,8 +10,9 @@ repository = "https://github.com/voxell-tech/motiongfx"
 
 [workspace.dependencies]
 # motiongfx
-motiongfx = { version = "0.3.0", path = "crates/motiongfx" }
-bevy_motiongfx = { version = "0.3.0", path = "crates/bevy_motiongfx" }
+motiongfx = { version = "0.3.0", path = "crates/motiongfx", default-features = false }
+motiongfx_scene = { version = "0.3.0", path = "crates/motiongfx_scene", default-features = false }
+bevy_motiongfx = { version = "0.3.0", path = "crates/bevy_motiongfx", default-features = false }
 peniko_motiongfx = { version = "0.3.0", path = "crates/peniko_motiongfx" }
 motiongfx_editor = { version = "0.3.0", path = "editor/motiongfx_editor" }
 motiongfx_editor_ui = { version = "0.3.0", path = "editor/motiongfx_editor_ui" }
@@ -25,15 +26,21 @@ bevy_platform = { version = "0.19", default-features = false }
 bevy_derive = { version = "0.19", default-features = false }
 bevy_math = { version = "0.19", default-features = false, features = [ "libm" ] }
 bevy_asset = { version = "0.19", default-features = false }
+bevy_reflect = { version = "0.19", default-features = false }
 bevy_time = { version = "0.19", default-features = false }
 bevy_transform = { version = "0.19", default-features = false, features = ["bevy-support"] }
 bevy_color = { version = "0.19", default-features = false }
 
 # other
 field_path = "0.4.1"
 typarena = { version = "0.1.0", features = ["send", "sync"] }
+sparse_map = { version = "0.3.0", default-features = false }
+libm = "0.2"
 nonempty = { version = "0.12", default-features = false }
 hashbrown = { version = "0.17", default-features = false }
+serde = { version = "1", default-features = false }
+educe = { version = "0.7.4", default-features = false }
+ron = { version = "0.12", default-features = false, features = ["std"] }
 peniko = { version = "0.6", default-features = false }
 vello = "0.9.0"
 winit = "0.30"
@@ -42,6 +49,10 @@ pollster = "0.4"
 [workspace.lints.clippy]
 redundant_type_annotations = "warn"
 
+# Use this commit until the `serde` feature is published to crates.io.
+[patch.crates-io]
+sparse_map = { git = "https://github.com/voxell-tech/sparse_map.git", branch = "nixon/serialization" }
+
 # Enable a small amount of optimization in the dev profile.
 [profile.dev]
 opt-level = 1

crates/bevy_motiongfx/Cargo.toml

@@ -13,6 +13,7 @@ repository.workspace = true
 [dependencies]
 # motiongfx
 motiongfx = { workspace = true }
+motiongfx_scene = { workspace = true, optional = true }
 
 # bevy
 bevy_ecs = { workspace = true }
@@ -24,6 +25,12 @@ bevy_time = { workspace = true }
 bevy_asset = { workspace = true, optional = true }
 bevy_transform = { workspace = true, optional = true }
 bevy_color = { workspace = true, optional = true }
+bevy_reflect = { workspace = true, optional = true, features = ["uuid"] }
+
+# other
+serde = { workspace = true, features = ["derive"] }
+sparse_map = { workspace = true, features = ["serde"], optional = true }
+ron = { workspace = true, optional = true }
 
 [dev-dependencies]
 bevy = { workspace = true, features = ["bevy_pbr"] }
@@ -33,7 +40,17 @@ workspace = true
 
 [features]
 default = ["std", "asset", "transform", "color"]
-std = ["motiongfx/std", "bevy_ecs/std", "bevy_app/std", "bevy_platform/std", "bevy_time/std"]
+std = ["motiongfx/std", "motiongfx_scene/std", "bevy_ecs/std", "bevy_app/std", "bevy_platform/std", "bevy_time/std"]
 asset = ["dep:bevy_asset"]
 transform = ["dep:bevy_transform"]
 color = ["dep:bevy_color"]
+scene = [
+    "dep:motiongfx_scene",
+    "dep:sparse_map",
+    "dep:ron",
+    "dep:bevy_reflect",
+    "bevy_math/serialize",
+    "bevy_transform/bevy_reflect",
+    "asset",
+    "transform",
+]

crates/bevy_motiongfx/src/lib.rs

@@ -1,23 +1,33 @@
 #![doc = include_str!("../README.md")]
 #![no_std]
 
+extern crate alloc;
+
 use bevy_app::prelude::*;
 use bevy_ecs::prelude::*;
 
 use crate::controller::ControllerPlugin;
 use crate::manager::MotionGfxManagerPlugin;
+#[cfg(feature = "scene")]
+use crate::scene::MotionGfxScenePlugin;
 
 pub mod controller;
 pub mod interpolation;
 pub mod manager;
 pub mod world;
 
+#[cfg(feature = "scene")]
+pub mod scene;
+
 pub mod prelude {
     pub use motiongfx::prelude::*;
 
     pub use crate::controller::{FixedRatePlayer, RealtimePlayer};
     pub use crate::manager::{MotionGfxManager, TimelineId};
     pub use crate::world::{BevyTimeline, BevyTimelineBuilder};
+
+    #[cfg(feature = "scene")]
+    pub use crate::scene::id::EntityUid;
 }
 
 pub use motiongfx;
@@ -40,6 +50,9 @@ impl Plugin for BevyMotionGfxPlugin {
                 .chain(),
         );
         app.add_plugins((MotionGfxManagerPlugin, ControllerPlugin));
+
+        #[cfg(feature = "scene")]
+        app.add_plugins(MotionGfxScenePlugin);
     }
 }
 

crates/bevy_motiongfx/src/manager.rs

@@ -99,6 +99,12 @@ impl MotionGfxManager {
         TimelineBuilder::new(&mut self.registry)
     }
 
+    /// The runtime [`Registry`] backing this manager's timelines.
+    #[cfg(feature = "scene")]
+    pub(crate) fn registry_mut(&mut self) -> &mut Registry {
+        &mut self.registry
+    }
+
     pub fn add_timeline(
         &mut self,
         timeline: BevyTimeline,

crates/bevy_motiongfx/src/scene.rs

@@ -0,0 +1,26 @@
+//! Serializable scenes for Bevy: a [`SceneBackend`](motiongfx_scene::backend::SceneBackend)
+//! implementation, plus loading one as a Bevy [`Asset`](bevy_asset::Asset).
+//! Gated behind the `scene` feature.
+
+use asset::{MotionGfxScene, SceneAssetLoader};
+use bevy_app::prelude::*;
+use bevy_asset::AssetApp as _;
+use id::{EntityUid, SceneUidMap, on_add_entity_uid, on_remove_entity_uid};
+
+pub mod asset;
+pub mod backend;
+pub mod id;
+pub mod value_pool;
+
+pub struct MotionGfxScenePlugin;
+
+impl Plugin for MotionGfxScenePlugin {
+    fn build(&self, app: &mut App) {
+        app.register_type::<EntityUid>()
+            .init_resource::<SceneUidMap>()
+            .init_asset::<MotionGfxScene>()
+            .register_asset_loader(SceneAssetLoader)
+            .add_observer(on_add_entity_uid)
+            .add_observer(on_remove_entity_uid);
+    }
+}

crates/bevy_motiongfx/src/scene/asset.rs

@@ -0,0 +1,69 @@
+//! Loads a [`Scene`] as a Bevy [`Asset`] from a `.mgx.ron` file.
+
+use alloc::vec::Vec;
+
+use bevy_asset::io::Reader;
+use bevy_asset::{Asset, AssetLoader, LoadContext};
+use bevy_ecs::error::BevyError;
+use bevy_reflect::TypePath;
+use motiongfx_scene::error::CompileError;
+use motiongfx_scene::scene::Scene;
+
+use crate::manager::{MotionGfxManager, TimelineId};
+use crate::scene::backend::{Backend, BackendRegistry};
+
+/// A [`Scene<BevyBackend>`], loadable as a Bevy asset.
+///
+/// A newtype rather than a blanket impl on `Scene` itself: `Asset`/
+/// `TypePath` are foreign traits and `Scene` is a foreign type from
+/// this crate's perspective, so the orphan rule requires a local
+/// wrapper.
+#[derive(Asset, TypePath)]
+pub struct MotionGfxScene(pub Scene<Backend>);
+
+impl MotionGfxScene {
+    /// Compiles this scene into a `BevyTimeline` through
+    /// `scene_registry`, then registers it on `motiongfx` exactly
+    /// like [`MotionGfxManager::add_timeline`]. This scene's subjects
+    /// must already be materialized - however the app chooses to do
+    /// that - so their [`EntityUid`](crate::scene::id::EntityUid)s
+    /// resolve through the world's
+    /// [`SceneUidMap`](crate::scene::id::SceneUidMap).
+    pub fn compile(
+        &self,
+        scene_registry: &BackendRegistry,
+        motiongfx: &mut MotionGfxManager,
+    ) -> Result<TimelineId, CompileError<Backend>> {
+        let timeline = motiongfx_scene::compile::compile(
+            &self.0,
+            scene_registry,
+            motiongfx.registry_mut(),
+        )?;
+        Ok(motiongfx.add_timeline(timeline))
+    }
+}
+
+#[derive(Default, TypePath)]
+pub struct SceneAssetLoader;
+
+impl AssetLoader for SceneAssetLoader {
+    type Asset = MotionGfxScene;
+    type Settings = ();
+    type Error = BevyError;
+
+    async fn load(
+        &self,
+        reader: &mut dyn Reader,
+        _settings: &Self::Settings,
+        _load_context: &mut LoadContext<'_>,
+    ) -> Result<Self::Asset, Self::Error> {
+        let mut bytes = Vec::new();
+        reader.read_to_end(&mut bytes).await?;
+        let scene = ron::de::from_bytes(&bytes)?;
+        Ok(MotionGfxScene(scene))
+    }
+
+    fn extensions(&self) -> &[&str] {
+        &["mgx.ron"]
+    }
+}