Hiding parent entity does not hide children

[AlexCMueller]

When I first tested this, I expected hiding a parent entity to also hide its children. This would be a useful behavior: an example would be making a rudimentary state system by having each state be represented by a root entity, and hiding the root entity of inactive states so the entire states aren't visible.

Below is a minimal example of a child still being visible after the parent is hidden, using bevy 0.3.0.

use bevy::prelude::*;

fn main() {
    App::build()
        .add_plugins(DefaultPlugins) 
        .add_startup_system(setup.system())
        .run();
}

fn setup(
    mut commands: Commands,
    mut materials: ResMut<Assets<ColorMaterial>>,
) {
    commands
        .spawn(Camera2dComponents::default())
        .spawn(())
        .with(Draw {
            is_visible: false,
            ..Default::default()
        })
        .with_children(|parent| {
            parent.spawn(SpriteComponents {
                material: materials.add(Color::BLUE.into()),
                sprite: Sprite::new(Vec2::new(50.0, 50.0)),
                ..Default::default()
            });
        });
}

[cart]

Totally agreed. Hiding a parent should hide all descendants

[kumorig]

Similar is true for Ui components using structure:

• NodeBundle
  • ButtonBundle
    • TextBundle
      • Text

Setting the NodeBundle.display to Display::None hides the button, but the text is still rendered, but in the wrong position.

Tested using current latest: 1e9a054

Example with NodeBundle using Display::None

use bevy::prelude::*;

fn main() {
    App::build()
        .add_plugins(DefaultPlugins)
        .add_startup_system(setup)
        .run();
}

fn setup(
    commands: &mut Commands,
    asset_server: Res<AssetServer>,
    mut materials: ResMut<Assets<ColorMaterial>>,
) {
    commands
        // ui camera
        .spawn(UiCameraBundle::default())
        .spawn(NodeBundle {
            material: materials.add(ColorMaterial::color(Color::rgb(0.5, 0.5, 0.5).into())),
            style: Style {
                // display: Display::Flex,
                display: Display::None,
                ..Default::default()
            },
            ..Default::default()
        })
        .with_children(|p| {
            p.spawn(ButtonBundle {
                style: Style {
                    size: Size::new(Val::Px(150.0), Val::Px(65.0)),
                    margin: Rect::all(Val::Auto),
                    justify_content: JustifyContent::Center,
                    align_items: AlignItems::Center,
                    ..Default::default()
                },
                material: materials.add(ColorMaterial::color(Color::rgb(0.7, 0.7, 0.7).into())),
                ..Default::default()
            })
            .with_children(|p| {
                p.spawn(TextBundle {
                    text: Text {
                        value: "Button".to_string(),
                        font: asset_server.load("fonts/FiraSans-Bold.ttf"),
                        style: TextStyle {
                            font_size: 40.0,
                            color: Color::rgb(0.9, 0.9, 0.9),
                            ..Default::default()
                        },
                    },
                    ..Default::default()
                });
            });
        });
}

Display::Flex

Display::None

(I just assume it's the same issue) Especially since the button disappears, you would also assume the button text (or bundle?) to be hidden.

[rparrett]

This workaround seems to be working for me. Posting here in case it's useful to anyone else.

fn set_visible_recursive(
    is_visible: bool,
    entity: Entity,
    visible_query: &mut Query<&mut Visible>,
    children_query: &Query<&Children>,
) {
    if let Ok(mut visible) = visible_query.get_mut(entity) {
        visible.is_visible = is_visible;
    }

    if let Ok(children) = children_query.get(entity) {
        for child in children.iter() {
            set_visible_recursive(is_visible, *child, visible_query, children_query);
        }
    }
}

fn some_system(
  children_query: Query<&Children>,
  mut visible_query: Query<&mut Visible>,
  // ...
) {
    // ...
    set_visible_recursive(visible, entity, &mut visible_query, &children_query);
}