d508923eb7
Examples creating a public type to derive `SystemParam` on were updated to create a private type where a public one is no longer needed. Resolves #1869
44 lines
1.1 KiB
Rust
44 lines
1.1 KiB
Rust
use bevy::{ecs::system::SystemParam, prelude::*};
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/// This example creates a SystemParam struct that counts the number of players
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fn main() {
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App::build()
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.insert_resource(PlayerCount(0))
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.add_startup_system(spawn.system())
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.add_system(count_players.system())
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.run();
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}
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pub struct Player;
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pub struct PlayerCount(usize);
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/// The SystemParam struct can contain any types that can also be included in a
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/// system function signature.
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///
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/// In this example, it includes a query and a mutable resource.
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#[derive(SystemParam)]
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struct PlayerCounter<'a> {
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players: Query<'a, &'static Player>,
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count: ResMut<'a, PlayerCount>,
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}
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impl<'a> PlayerCounter<'a> {
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fn count(&mut self) {
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self.count.0 = self.players.iter().len();
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}
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}
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/// Spawn some players to count
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fn spawn(mut commands: Commands) {
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commands.spawn().insert(Player);
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commands.spawn().insert(Player);
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commands.spawn().insert(Player);
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}
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/// The SystemParam can be used directly in a system argument.
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fn count_players(mut counter: PlayerCounter) {
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counter.count();
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println!("{} players in the game", counter.count.0);
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}
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