A bug, or am i misusing?

[Taswen]

What's your problem

I am learning bevy0.6 by building a 2048 game. I need a sprite that can display changing number to make block. But none of bevy's existing bundles meets the requirement(or I didn't find it).

Then I tried to use hierarchy. However, I encountered a problem that is not sure if it is a bug. The number(created by Text2dBundle) that should be in the sprite(created by SpriteBundle) center is no longer located by its father after more spawns.

Show me the code

The following is the problem part that I extracted as a demo.

use bevy::prelude::*;
use rand::prelude::*;

#[derive(PartialEq)]
struct GameRunInfo {
    block_index: Box<Vec<Vec<Option<Entity>>>>,
    reset: bool,
    adding: bool,
    count: usize,
}

#[derive(Component, Clone)]
struct Block;

fn random_generate_block(
    commands: &mut Commands,
    game_info: &mut GameRunInfo,
    font: &Handle<Font>,
) {
    let mut rng = thread_rng();
    if game_info.count < 16 {
        loop {
            let x = rng.gen_range(0..16usize);
            let row = x / 4;
            let col = x % 4;
            if game_info.block_index[row][col] == None {
                let r_num = rng.gen_range(1..=2usize) * 2;
                let block_id = commands
                    .spawn_bundle(SpriteBundle {
                        sprite: Sprite {
                            color: Color::hex("cff0b455").unwrap(),
                            custom_size: Some(Vec2::new(65., 65.)),
                            ..Default::default()
                        },
                        transform: Transform {
                            translation: Vec3::new(
                                col as f32 * 75. + 37.5 - 150.,
                                row as f32 * 75. + 37.5 - 150.,
                                0.01,
                            ),
                            ..Default::default()
                        },
                        ..Default::default()
                    })
                    .insert(Block)
                    .id();
                // add number as block's child
                commands
                    .spawn_bundle(Text2dBundle {
                        text: Text::with_section(
                            r_num.to_string(),
                            TextStyle {
                                font: font.clone(),
                                font_size: 40.0,
                                color: Color::WHITE,
                            },
                            TextAlignment {
                                vertical: VerticalAlign::Center,
                                horizontal: HorizontalAlign::Center,
                            },
                        ),
                        transform: Transform {
                            translation: Vec3::new(0., 0., 0.02),
                            ..Default::default()
                        },
                        ..Default::default()
                    })
                    .insert(Parent(block_id));
                // record
                game_info.block_index[row][col] = Some(block_id);
                game_info.count += 1;
                println!("new block {}: {} {}", r_num, row, col);
                break;
            }
        }
    } else {
        println!("FULL! R to restart");
    }
}

fn reset_system(
    mut commands: Commands,
    mut game_info: ResMut<GameRunInfo>,
    mut num_blocks: Query<Entity, With<Block>>,
    font: Res<Handle<Font>>,
    ky: Res<Input<KeyCode>>,
) {
    if !game_info.reset && ky.just_pressed(KeyCode::R) {
        println!("Press R");
        // delete all block and num
        for id in num_blocks.iter_mut() {
            commands.entity(id).despawn_recursive();
        }
        // re-create index table
        game_info.block_index = Box::new(vec![vec![Option::<Entity>::None; 4]; 4]);
        game_info.count = 0;
        // re-generate block
        random_generate_block(&mut commands, &mut game_info, &font);
        game_info.reset = true;
    }

    if ky.just_released(KeyCode::R) {
        game_info.reset = false;
    }
}
fn random_generate_system(
    mut commands: Commands,
    mut game_info: ResMut<GameRunInfo>,
    font: Res<Handle<Font>>,
    ky: Res<Input<KeyCode>>,
) {
    if !game_info.adding && ky.just_pressed(KeyCode::A) {
        println!("Press A");
        // re-generate block
        random_generate_block(&mut commands, &mut game_info, &font);
        game_info.adding = true;
    }

    if ky.just_released(KeyCode::A) {
        game_info.adding = false;
    }
}

fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
    let mut game_info = GameRunInfo {
        block_index: Box::new(vec![vec![Option::<Entity>::None; 4]; 4]),
        reset: false,
        adding: false,
        count: 0,
    };
    let font = asset_server.load("fonts/FiraSans-Bold.ttf");
    // cameras
    commands.spawn_bundle(OrthographicCameraBundle::new_2d());
    commands.spawn_bundle(UiCameraBundle::default());

    random_generate_block(&mut commands, &mut game_info, &font);
    commands.insert_resource(game_info);
    commands.insert_resource(font);
}

fn main() {
    App::new()
        .insert_resource(WindowDescriptor {
            width: 300.,
            height: 420.,
            ..Default::default()
        })
        .add_plugins(DefaultPlugins)
        .add_startup_system(setup)
        .add_system(random_generate_system)
        .add_system(reset_system)
        .run();
}

More information

Version: bevy-0.6-nightly
Crates: rand-0.8
Platform: Win10

If it is my fault, please point out my mistake, thanks. And if it is a bug, I will create an issue.

[rparrett]

I believe you're seeing #1807 and the workaround mentioned in that issue should fix you up.

[DJMcNab]

The reason it works for the first one is because the parent update system is also added in the startup schedule, but the actual propogation is handled in 'frame' 1

[Taswen]

So, it’s a less urgent bug? Anyway, thanks.