bevy/examples/2d/texture_atlas.rs
Matthias Schiffer 85743ce49e asset: make HandleUntyped::id private (#7076)
# Objective

It is currently possible to break reference counting for assets by creating a strong `HandleUntyped` and then modifying the `id` field before dropping the handle. This should not be allowed.

## Solution

Change the `id` field visibility to private and add a getter instead. The same change was previously done for `Handle<T>` in #6176, but `HandleUntyped` was forgotten.

---

## Migration Guide

- Instead of directly accessing the ID of a `HandleUntyped` as `handle.id`, use the new getter `handle.id()`.
2023-01-04 23:40:43 +00:00

87 lines
3 KiB
Rust

//! In this example we generate a new texture atlas (sprite sheet) from a folder containing
//! individual sprites.
use bevy::{asset::LoadState, prelude::*};
fn main() {
App::new()
.init_resource::<RpgSpriteHandles>()
.add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest())) // prevents blurry sprites
.add_state(AppState::Setup)
.add_system_set(SystemSet::on_enter(AppState::Setup).with_system(load_textures))
.add_system_set(SystemSet::on_update(AppState::Setup).with_system(check_textures))
.add_system_set(SystemSet::on_enter(AppState::Finished).with_system(setup))
.run();
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
enum AppState {
Setup,
Finished,
}
#[derive(Resource, Default)]
struct RpgSpriteHandles {
handles: Vec<HandleUntyped>,
}
fn load_textures(mut rpg_sprite_handles: ResMut<RpgSpriteHandles>, asset_server: Res<AssetServer>) {
rpg_sprite_handles.handles = asset_server.load_folder("textures/rpg").unwrap();
}
fn check_textures(
mut state: ResMut<State<AppState>>,
rpg_sprite_handles: ResMut<RpgSpriteHandles>,
asset_server: Res<AssetServer>,
) {
if let LoadState::Loaded = asset_server
.get_group_load_state(rpg_sprite_handles.handles.iter().map(|handle| handle.id()))
{
state.set(AppState::Finished).unwrap();
}
}
fn setup(
mut commands: Commands,
rpg_sprite_handles: Res<RpgSpriteHandles>,
asset_server: Res<AssetServer>,
mut texture_atlases: ResMut<Assets<TextureAtlas>>,
mut textures: ResMut<Assets<Image>>,
) {
let mut texture_atlas_builder = TextureAtlasBuilder::default();
for handle in &rpg_sprite_handles.handles {
let handle = handle.typed_weak();
let Some(texture) = textures.get(&handle) else {
warn!("{:?} did not resolve to an `Image` asset.", asset_server.get_handle_path(handle));
continue;
};
texture_atlas_builder.add_texture(handle, texture);
}
let texture_atlas = texture_atlas_builder.finish(&mut textures).unwrap();
let texture_atlas_texture = texture_atlas.texture.clone();
let vendor_handle = asset_server.get_handle("textures/rpg/chars/vendor/generic-rpg-vendor.png");
let vendor_index = texture_atlas.get_texture_index(&vendor_handle).unwrap();
let atlas_handle = texture_atlases.add(texture_atlas);
// set up a scene to display our texture atlas
commands.spawn(Camera2dBundle::default());
// draw a sprite from the atlas
commands.spawn(SpriteSheetBundle {
transform: Transform {
translation: Vec3::new(150.0, 0.0, 0.0),
scale: Vec3::splat(4.0),
..default()
},
sprite: TextureAtlasSprite::new(vendor_index),
texture_atlas: atlas_handle,
..default()
});
// draw the atlas itself
commands.spawn(SpriteBundle {
texture: texture_atlas_texture,
transform: Transform::from_xyz(-300.0, 0.0, 0.0),
..default()
});
}