feat: add entity handles and a bevy channel abstraction

Signed-off-by: Schmarni <marnistromer@gmail.com>

src/core/bevy_channel.rs

@@ -0,0 +1,32 @@
+use std::sync::OnceLock;
+
+use bevy::prelude::*;
+use tokio::sync::mpsc::{self, error::TryRecvError};
+
+#[derive(Resource)]
+pub struct BevyChannelReader<T: Send + Sync + 'static>(mpsc::UnboundedReceiver<T>);
+pub struct BevyChannel<T: Send + Sync + 'static>(OnceLock<mpsc::UnboundedSender<T>>);
+impl<T: Send + Sync + 'static> BevyChannel<T> {
+	pub const fn new() -> Self {
+		Self(OnceLock::new())
+	}
+	pub fn init(&self, app: &mut App) {
+		let (tx, rx) = mpsc::unbounded_channel();
+		self.0.set(tx).unwrap();
+		app.insert_resource(BevyChannelReader(rx));
+	}
+	pub fn send(&self, msg: T) -> Option<()> {
+		self.0.get()?.send(msg).ok()
+	}
+}
+
+impl<T: Send + Sync + 'static> BevyChannelReader<T> {
+	pub fn read(&mut self) -> Option<T> {
+		match self.0.try_recv() {
+			Ok(v) => Some(v),
+			Err(TryRecvError::Disconnected) => panic!("bevy channel should never disconnect"),
+			Err(TryRecvError::Empty) => None,
+		}
+	}
+}
+

src/core/color.rs

@@ -0,0 +1,12 @@
+use stardust_xr::values::color::{AlphaColor, Rgb, color_space::LinearRgb};
+
+pub trait ColorConvert {
+	fn to_bevy(&self) -> bevy::color::Color;
+}
+// even tho its supposed to be linear the values have to be interpreted as Srgba to produce the
+// correct result because StereoKit used Srgba while it was assumed that is uses linear rgba
+impl ColorConvert for AlphaColor<f32, Rgb<f32, LinearRgb>> {
+	fn to_bevy(&self) -> bevy::color::Color {
+		bevy::color::Color::srgba(self.c.r, self.c.g, self.c.b, self.a)
+	}
+}

src/core/entity_handle.rs

@@ -0,0 +1,33 @@
+use bevy::prelude::*;
+
+use super::bevy_channel::{BevyChannel, BevyChannelReader};
+pub struct EntityHandlePlugin;
+
+impl Plugin for EntityHandlePlugin {
+	fn build(&self, app: &mut App) {
+		DESTROY.init(app);
+		app.add_systems(PreUpdate, despawn);
+	}
+}
+
+fn despawn(mut cmds: Commands, mut reader: ResMut<BevyChannelReader<Entity>>) {
+	while let Some(e) = reader.read() {
+		cmds.entity(e).despawn();
+	}
+}
+
+static DESTROY: BevyChannel<Entity> = BevyChannel::new();
+#[derive(Deref, DerefMut, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
+pub struct EntityHandle(pub Entity);
+impl Drop for EntityHandle {
+	fn drop(&mut self) {
+		if DESTROY.send(self.0).is_none() {
+			error!("Entity Destroy channel not open");
+		}
+	}
+}
+impl From<Entity> for EntityHandle {
+	fn from(value: Entity) -> Self {
+		Self(value)
+	}
+}

src/core/mod.rs

@@ -8,3 +8,5 @@ pub mod resource;
 pub mod scenegraph;
 pub mod task;
 pub mod color;
+pub mod entity_handle;
+pub mod bevy_channel;