mirror of
https://github.com/bevyengine/bevy
synced 2024-11-22 20:53:53 +00:00
81b53d15d4
Resolves #1253 #1562 This makes the Commands apis consistent with World apis. This moves to a "type state" pattern (like World) where the "current entity" is stored in an `EntityCommands` builder. In general this tends to cuts down on indentation and line count. It comes at the cost of needing to type `commands` more and adding more semicolons to terminate expressions. I also added `spawn_bundle` to Commands because this is a common enough operation that I think its worth providing a shorthand.
92 lines
2.9 KiB
Rust
92 lines
2.9 KiB
Rust
use bevy::{prelude::*, scene::InstanceId};
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fn main() {
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App::build()
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.insert_resource(Msaa { samples: 4 })
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.add_plugins(DefaultPlugins)
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.insert_resource(SceneInstance::default())
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.add_startup_system(setup.system())
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.add_system(scene_update.system())
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.add_system(move_scene_entities.system())
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.run();
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}
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// Resource to hold the scene `instance_id` until it is loaded
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#[derive(Default)]
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struct SceneInstance(Option<InstanceId>);
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// Component that will be used to tag entities in the scene
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struct EntityInMyScene;
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fn setup(
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mut commands: Commands,
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asset_server: Res<AssetServer>,
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mut scene_spawner: ResMut<SceneSpawner>,
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mut scene_instance: ResMut<SceneInstance>,
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) {
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commands.spawn_bundle(LightBundle {
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transform: Transform::from_xyz(4.0, 5.0, 4.0),
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..Default::default()
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});
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commands.spawn_bundle(PerspectiveCameraBundle {
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transform: Transform::from_xyz(1.05, 0.9, 1.5)
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.looking_at(Vec3::new(0.0, 0.3, 0.0), Vec3::Y),
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..Default::default()
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});
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// Spawn the scene as a child of another entity. This first scene will be translated backward
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// with its parent
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commands
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.spawn_bundle((
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Transform::from_xyz(0.0, 0.0, -1.0),
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GlobalTransform::identity(),
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))
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.with_children(|parent| {
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parent.spawn_scene(asset_server.load("models/FlightHelmet/FlightHelmet.gltf#Scene0"));
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});
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// Spawn a second scene, and keep its `instance_id`
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let instance_id =
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scene_spawner.spawn(asset_server.load("models/FlightHelmet/FlightHelmet.gltf#Scene0"));
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scene_instance.0 = Some(instance_id);
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}
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// This system will wait for the scene to be ready, and then tag entities from
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// the scene with `EntityInMyScene`. All entities from the second scene will be
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// tagged
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fn scene_update(
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mut commands: Commands,
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scene_spawner: Res<SceneSpawner>,
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scene_instance: Res<SceneInstance>,
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mut done: Local<bool>,
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) {
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if !*done {
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if let Some(instance_id) = scene_instance.0 {
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if let Some(entity_iter) = scene_spawner.iter_instance_entities(instance_id) {
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entity_iter.for_each(|entity| {
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commands.entity(entity).insert(EntityInMyScene);
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});
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*done = true;
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}
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}
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}
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}
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// This system will move all entities with component `EntityInMyScene`, so all
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// entities from the second scene
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fn move_scene_entities(
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time: Res<Time>,
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mut scene_entities: Query<&mut Transform, With<EntityInMyScene>>,
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) {
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let mut direction = 1.;
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let mut scale = 1.;
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for mut transform in scene_entities.iter_mut() {
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transform.translation = Vec3::new(
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scale * direction * time.seconds_since_startup().sin() as f32 / 20.,
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0.,
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time.seconds_since_startup().cos() as f32 / 20.,
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);
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direction *= -1.;
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scale += 0.5;
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}
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}
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