f90248b052
# Objective - Examples containing `ResMut`s that are never mutated can be confusing for readers. ## Solution - Changes them to `Res`.
96 lines
3.2 KiB
Rust
96 lines
3.2 KiB
Rust
//! In this example we generate a new texture atlas (sprite sheet) from a folder containing
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//! individual sprites.
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use bevy::{asset::LoadedFolder, prelude::*};
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest())) // prevents blurry sprites
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.add_state::<AppState>()
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.add_systems(OnEnter(AppState::Setup), load_textures)
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.add_systems(Update, check_textures.run_if(in_state(AppState::Setup)))
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.add_systems(OnEnter(AppState::Finished), setup)
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.run();
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}
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#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, States)]
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enum AppState {
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#[default]
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Setup,
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Finished,
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}
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#[derive(Resource, Default)]
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struct RpgSpriteFolder(Handle<LoadedFolder>);
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fn load_textures(mut commands: Commands, asset_server: Res<AssetServer>) {
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// load multiple, individual sprites from a folder
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commands.insert_resource(RpgSpriteFolder(asset_server.load_folder("textures/rpg")));
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}
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fn check_textures(
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mut next_state: ResMut<NextState<AppState>>,
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rpg_sprite_folder: Res<RpgSpriteFolder>,
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mut events: EventReader<AssetEvent<LoadedFolder>>,
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) {
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// Advance the `AppState` once all sprite handles have been loaded by the `AssetServer`
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for event in events.read() {
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if event.is_loaded_with_dependencies(&rpg_sprite_folder.0) {
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next_state.set(AppState::Finished);
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}
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}
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}
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fn setup(
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mut commands: Commands,
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rpg_sprite_handles: Res<RpgSpriteFolder>,
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asset_server: Res<AssetServer>,
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loaded_folders: Res<Assets<LoadedFolder>>,
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mut texture_atlases: ResMut<Assets<TextureAtlas>>,
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mut textures: ResMut<Assets<Image>>,
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) {
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// Build a `TextureAtlas` using the individual sprites
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let mut texture_atlas_builder = TextureAtlasBuilder::default();
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let loaded_folder = loaded_folders.get(&rpg_sprite_handles.0).unwrap();
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for handle in loaded_folder.handles.iter() {
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let id = handle.id().typed_unchecked::<Image>();
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let Some(texture) = textures.get(id) else {
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warn!(
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"{:?} did not resolve to an `Image` asset.",
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handle.path().unwrap()
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);
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continue;
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};
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texture_atlas_builder.add_texture(id, texture);
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}
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let texture_atlas = texture_atlas_builder.finish(&mut textures).unwrap();
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let texture_atlas_texture = texture_atlas.texture.clone();
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let vendor_handle = asset_server
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.get_handle("textures/rpg/chars/vendor/generic-rpg-vendor.png")
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.unwrap();
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let vendor_index = texture_atlas.get_texture_index(&vendor_handle).unwrap();
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let atlas_handle = texture_atlases.add(texture_atlas);
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// set up a scene to display our texture atlas
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commands.spawn(Camera2dBundle::default());
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// draw a sprite from the atlas
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commands.spawn(SpriteSheetBundle {
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transform: Transform {
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translation: Vec3::new(150.0, 0.0, 0.0),
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scale: Vec3::splat(4.0),
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..default()
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},
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sprite: TextureAtlasSprite::new(vendor_index),
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texture_atlas: atlas_handle,
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..default()
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});
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// draw the atlas itself
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commands.spawn(SpriteBundle {
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texture: texture_atlas_texture,
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transform: Transform::from_xyz(-300.0, 0.0, 0.0),
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..default()
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});
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}
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