visibility.rs

use bevy::prelude::*;
use bevy_ecs_tilemap::prelude::*;
use rand::{thread_rng, Rng};

mod helpers;

fn startup(mut commands: Commands, asset_server: Res<AssetServer>) {
    commands.spawn(Camera2dBundle::default());

    let texture_handle: Handle<Image> = asset_server.load("tiles.png");

    let map_size = TilemapSize { x: 32, y: 32 };
    let mut tile_storage = TileStorage::empty(map_size);
    let tilemap_entity = commands.spawn_empty().id();

    for x in 0..32u32 {
        for y in 0..32u32 {
            let tile_pos = TilePos { x, y };
            let tile_entity = commands
                .spawn(TileBundle {
                    position: tile_pos,
                    tilemap_id: TilemapId(tilemap_entity),
                    ..Default::default()
                })
                .id();
            tile_storage.set(&tile_pos, tile_entity);
        }
    }

    let tile_size = TilemapTileSize { x: 16.0, y: 16.0 };
    let grid_size = tile_size.into();
    let map_type = TilemapType::default();

    commands.entity(tilemap_entity).insert((
        TilemapBundle {
            grid_size,
            map_type,
            size: map_size,
            storage: tile_storage,
            texture: TilemapTexture::Single(texture_handle),
            tile_size,
            transform: get_tilemap_center_transform(&map_size, &grid_size, &map_type, 0.0),
            ..Default::default()
        },
        LastUpdate::default(),
    ));
}

#[derive(Default, Component)]
struct LastUpdate {
    value: f64,
}

fn remove_tiles(
    time: Res<Time>,
    mut last_update_query: Query<(&mut LastUpdate, &TileStorage)>,
    mut tile_query: Query<&mut TileVisible>,
) {
    let current_time = time.elapsed_seconds_f64();
    for (mut last_update, tile_storage) in last_update_query.iter_mut() {
        // Remove a tile every half second.
        if (current_time - last_update.value) > 0.1 {
            let mut random = thread_rng();
            let position = TilePos {
                x: random.gen_range(0..32),
                y: random.gen_range(0..32),
            };

            // Instead of removing the tile entity we want to hide the tile by removing the Visible component.
            if let Some(tile_entity) = tile_storage.get(&position) {
                let mut visibility = tile_query.get_mut(tile_entity).unwrap();
                visibility.0 = !visibility.0;
            }

            last_update.value = current_time;
        }
    }
}

fn main() {
    App::new()
        .add_plugins((
            DefaultPlugins
                .set(WindowPlugin {
                    primary_window: Some(Window {
                        title: String::from("Visibility Example"),
                        ..Default::default()
                    }),
                    ..default()
                })
                .set(ImagePlugin::default_nearest()),
            TilemapPlugin,
        ))
        .add_systems(Startup, startup)
        .add_systems(Update, helpers::camera::movement)
        .add_systems(Update, remove_tiles)
        .run();
}