Render Graph as Systems - Bevy

The RenderGraph API has been removed. Render passes are now systems that run in Core3d or Core2d schedules.

Before:

rust,ignore

impl ViewNode for MyNode {
    type ViewQuery = (&'static ExtractedCamera, &'static ViewTarget);

    fn run<'w>(
        &self,
        _graph: &mut RenderGraphContext,
        render_context: &mut RenderContext<'w>,
        (camera, target): QueryItem<'w, Self::ViewQuery>,
        world: &'w World,
    ) -> Result<(), NodeRunError> {
        // ...
    }
}

render_app
    .add_render_graph_node::<ViewNodeRunner<MyNode>>(Core3d, MyLabel)
    .add_render_graph_edges(Core3d, (Node3d::Foo, MyLabel, Node3d::Bar));

After:

rust,ignore

pub fn my_render_pass(
    world: &World,
    view: ViewQuery<(&ExtractedCamera, &ViewTarget)>,
    mut ctx: RenderContext,
) {
    let (camera, target) = view.into_inner();
    // ...
}

render_app.add_systems(
    Core3d,
    my_render_pass
        .after(foo_pass)
        .before(bar_pass)
        .in_set(Core3dSystems::MainPass),
);

The ViewNode trait is replaced by a regular system using the ViewQuery parameter. RenderContext is now a system parameter instead of being passed as &mut. Use .before() / .after() with the actual system functions (e.g., main_opaque_pass_3d) rather than Node3d labels.

System sets Core3dSystems::Prepass, MainPass, and PostProcess are available for coarse ordering. The RenderGraph schedule remains as the top-level schedule for non-camera rendering.