RenderLayers does not affect SceneBundle

[ostwilkens]

Bevy version

Latest bevy git commit at time of writing, 8f721d8d0ac2e14a46051175f6d3394ed87c7214.

Relevant system information

`AdapterInfo { name: "NVIDIA GeForce RTX 2070", vendor: 4318, device: 7938, device_type: DiscreteGpu, backend: Vulkan }`

What you did

I noticed this issue in my current project. I also tried adding the component RenderLayers::layer(1) to the SceneBundle in the split_screen example.

What went wrong

The component has no effect.

[tim-blackbird]

RenderLayers only applies to the entity it is on, it does not (currently) apply to children of that entity.

[ostwilkens]

RenderLayers only applies to the entity it is on, it does not (currently) apply to children of that entity.

I see! It probably should though, right? In that sense I guess this is a feature request.

[alice-i-cecile]

Related to #838. This is effectively the same feature, but for render layers.

[ostwilkens]

Related to #838. This is effectively the same feature, but for render layers.

Oh yeah!
Though I would expect RenderLayers to be overrideable by a child.

[asafigan]

I would like to propose a similar pattern to Visibility. Having a ComputedRenderLayers which is used to propagate the render layer down to children. Adding RenderLayers to a component will override this propagation and start a new propagation. The question is if this should be added to SpatialBundle and all related bundles or added dynamically by a system to call children of a entity with a RenderLayers component.

[dmlary]

Awful brute-force workaround for this issue. Add a PropagateRenderLayers component, then a few systems to copy the RenderLayers component down to child entities for any entity with PropagateRenderLayers.

#[derive(Component)]
struct PropagateRenderLayers;

fn propagate_render_layers_added(
    mut cmds: Commands,
    parents: Query<(&RenderLayers, &Children), (Added<PropagateRenderLayers>, With<Children>)>,
) {
    for (render_layers, children) in &parents {
        for child in children {
            cmds.entity(*child)
                .insert((PropagateRenderLayers, *render_layers));
        }
    }
}

fn propagate_render_layers_changed(
    mut cmds: Commands,
    parents: Query<
        (&RenderLayers, &Children),
        (
            With<PropagateRenderLayers>,
            With<Children>,
            Changed<RenderLayers>,
        ),
    >,
) {
    for (render_layers, children) in &parents {
        for child in children {
            cmds.entity(*child)
                .insert(*render_layers);
        }
    }
}

fn propagate_render_layers_add_child(
    mut cmds: Commands,
    parents: Query<(&RenderLayers, &Children), (With<PropagateRenderLayers>, Changed<Children>)>,
) {
    for (render_layers, children) in &parents {
        for child in children {
            cmds.entity(*child)
                .insert((PropagateRenderLayers, *render_layers));
        }
    }
}

[dmlary]

Or just use https://github.com/nicopap/bevy-scene-hook, which is much better than my workaround above