Some work on ecs scenes

core/scenes/src/canvas/sprites.rs

@@ -1,2 +1,8 @@
+use crate::{Component, Event};
+
 /// A component that renders a sprite.
 pub struct SpriteComponent {}
+
+impl Component for SpriteComponent {
+  fn on_event(&self, event: &dyn Event) {}
+}

core/scenes/src/lib.rs

@@ -6,26 +6,33 @@ pub use spatial::*;
 mod canvas;
 mod spatial;
 
+use common::Camera;
+use graphics::{RenderFrame, RenderPass, RenderQueue, RenderScene};
+
 pub struct AwakeEvent;
 pub struct StartEvent;
 pub struct UpdateEvent;
-pub struct DrawEvent;
 pub struct DestroyEvent;
 
+pub struct DrawEvent<'a> {
+  queue: &'a mut RenderQueue,
+}
+
 pub trait Event {}
 
 impl Event for AwakeEvent {}
 impl Event for StartEvent {}
 impl Event for UpdateEvent {}
-impl Event for DrawEvent {}
 impl Event for DestroyEvent {}
 
+impl<'a> Event for DrawEvent<'a> {}
+
 pub trait Component {
-  fn on_event(&mut self, event: &dyn Event);
+  fn on_event(&self, event: &dyn Event);
 }
 
 pub trait System {
-  fn on_event(&mut self, event: &dyn Event);
+  fn on_event(&self, event: &dyn Event);
 }
 
 pub trait IntoSystem {
@@ -46,10 +53,24 @@ struct Entity {
 
 impl Scene {
   /// Emits an event into the scene graph.
-  pub fn emit(&mut self, event: &dyn Event) {
+  pub fn emit(&self, event: &mut dyn Event) {
     // propagate the event to all systems
-    for system in &mut self.systems {
+    for system in &self.systems {
       system.on_event(event);
     }
   }
 }
+
+pub struct SceneRenderPass {}
+
+impl RenderScene for Scene {
+  fn cameras(&self) -> Vec<&Self::Camera> {
+    vec![]
+  }
+}
+
+impl RenderPass<Scene> for SceneRenderPass {
+  fn render_camera(&mut self, scene: &Scene, _camera: &dyn Camera, frame: &mut RenderFrame<'_>) {
+    scene.emit(&mut DrawEvent { queue: frame.queue });
+  }
+}