mirror of
https://github.com/bevyengine/bevy
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51a5070cd2
# Objective The vast majority of `.single()` usage I've seen is immediately followed by a `.unwrap()`. Since it seems most people use it without handling the error, I think making it easier to just get what you want fast while also having a more verbose alternative when you want to handle the error could help. ## Solution Instead of having a lot of `.unwrap()` everywhere, this PR introduces a `try_single()` variant that behaves like the current `.single()` and make the new `.single()` panic on error.
92 lines
3 KiB
Rust
92 lines
3 KiB
Rust
use bevy::{
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diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
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math::Quat,
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prelude::*,
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render::camera::Camera,
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sprite::SpriteSettings,
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};
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use rand::Rng;
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const CAMERA_SPEED: f32 = 1000.0;
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/// This example is for performance testing purposes.
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/// See https://github.com/bevyengine/bevy/pull/1492
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fn main() {
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App::new()
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.add_plugin(LogDiagnosticsPlugin::default())
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.add_plugin(FrameTimeDiagnosticsPlugin::default())
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.insert_resource(SpriteSettings {
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// NOTE: this is an experimental feature that doesn't work in all cases
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frustum_culling_enabled: true,
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})
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.add_plugins(DefaultPlugins)
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.add_startup_system(setup)
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.add_system(tick_system.label("Tick"))
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.add_system(move_camera_system.after("Tick"))
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.run()
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}
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fn setup(
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mut commands: Commands,
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assets: Res<AssetServer>,
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mut materials: ResMut<Assets<ColorMaterial>>,
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) {
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let mut rng = rand::thread_rng();
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let tile_size = Vec2::splat(64.0);
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let map_size = Vec2::splat(320.0);
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let half_x = (map_size.x / 2.0) as i32;
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let half_y = (map_size.y / 2.0) as i32;
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let sprite_handle = materials.add(assets.load("branding/icon.png").into());
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// Spawns the camera
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commands
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.spawn()
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.insert_bundle(OrthographicCameraBundle::new_2d())
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.insert(Timer::from_seconds(1.0, true))
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.insert(Transform::from_xyz(0.0, 0.0, 1000.0));
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// Builds and spawns the sprites
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let mut sprites = vec![];
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for y in -half_y..half_y {
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for x in -half_x..half_x {
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let position = Vec2::new(x as f32, y as f32);
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let translation = (position * tile_size).extend(rng.gen::<f32>());
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let rotation = Quat::from_rotation_z(rng.gen::<f32>());
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let scale = Vec3::splat(rng.gen::<f32>() * 2.0);
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sprites.push(SpriteBundle {
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material: sprite_handle.clone(),
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transform: Transform {
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translation,
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rotation,
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scale,
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},
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sprite: Sprite::new(tile_size),
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..Default::default()
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});
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}
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}
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commands.spawn_batch(sprites);
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}
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// System for rotating and translating the camera
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fn move_camera_system(time: Res<Time>, mut camera_query: Query<&mut Transform, With<Camera>>) {
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let mut camera_transform = camera_query.single_mut();
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camera_transform.rotate(Quat::from_rotation_z(time.delta_seconds() * 0.5));
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*camera_transform = *camera_transform
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* Transform::from_translation(Vec3::X * CAMERA_SPEED * time.delta_seconds());
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}
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// System for printing the number of sprites on every tick of the timer
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fn tick_system(time: Res<Time>, sprites_query: Query<&Sprite>, mut timer_query: Query<&mut Timer>) {
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let mut timer = timer_query.single_mut();
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timer.tick(time.delta());
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if timer.just_finished() {
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info!("Sprites: {}", sprites_query.iter().count(),);
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}
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}
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