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https://github.com/bevyengine/bevy
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c893b99224
This can be your 6 months post-christmas present. # Objective - Make `.system` optional - yeet - It's ugly - Alternative title: `.system` is dead; long live `.system` - **yeet** ## Solution - Use a higher ranked lifetime, and some trait magic. N.B. This PR does not actually remove any `.system`s, except in a couple of examples. Once this is merged we can do that piecemeal across crates, and decide on syntax for labels.
82 lines
2.9 KiB
Rust
82 lines
2.9 KiB
Rust
use bevy::{asset::LoadState, prelude::*, sprite::TextureAtlasBuilder};
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/// 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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fn main() {
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App::build()
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.init_resource::<RpgSpriteHandles>()
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.add_plugins(DefaultPlugins)
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.add_state(AppState::Setup)
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.add_system_set(SystemSet::on_enter(AppState::Setup).with_system(load_textures))
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.add_system_set(SystemSet::on_update(AppState::Setup).with_system(check_textures))
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.add_system_set(SystemSet::on_enter(AppState::Finished).with_system(setup))
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.run();
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}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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enum AppState {
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Setup,
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Finished,
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}
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#[derive(Default)]
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struct RpgSpriteHandles {
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handles: Vec<HandleUntyped>,
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}
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fn load_textures(mut rpg_sprite_handles: ResMut<RpgSpriteHandles>, asset_server: Res<AssetServer>) {
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rpg_sprite_handles.handles = asset_server.load_folder("textures/rpg").unwrap();
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}
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fn check_textures(
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mut state: ResMut<State<AppState>>,
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rpg_sprite_handles: ResMut<RpgSpriteHandles>,
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asset_server: Res<AssetServer>,
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) {
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if let LoadState::Loaded =
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asset_server.get_group_load_state(rpg_sprite_handles.handles.iter().map(|handle| handle.id))
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{
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state.set(AppState::Finished).unwrap();
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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<RpgSpriteHandles>,
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asset_server: Res<AssetServer>,
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mut texture_atlases: ResMut<Assets<TextureAtlas>>,
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mut textures: ResMut<Assets<Texture>>,
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mut materials: ResMut<Assets<ColorMaterial>>,
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) {
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let mut texture_atlas_builder = TextureAtlasBuilder::default();
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for handle in rpg_sprite_handles.handles.iter() {
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let texture = textures.get(handle).unwrap();
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texture_atlas_builder.add_texture(handle.clone_weak().typed::<Texture>(), 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.get_handle("textures/rpg/chars/vendor/generic-rpg-vendor.png");
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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_bundle(OrthographicCameraBundle::new_2d());
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// draw a sprite from the atlas
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commands.spawn_bundle(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::default()
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},
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sprite: TextureAtlasSprite::new(vendor_index as u32),
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texture_atlas: atlas_handle,
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..Default::default()
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});
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// draw the atlas itself
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commands.spawn_bundle(SpriteBundle {
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material: materials.add(texture_atlas_texture.into()),
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transform: Transform::from_xyz(-300.0, 0.0, 0.0),
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..Default::default()
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});
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}
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