immediate_stats 0.5.0

//! A very simple example using Bevy. Requires the `bevy` feature flag.
//! There are two other versions of this example, one using a simple main loop and the other using Bevy Auto Plugin.

use bevy::prelude::*;
use immediate_stats::*;

fn main() {
    App::new()
        .add_plugins((MinimalPlugins, ImmediateStatsPlugin, SpeedPlugin))
        .run();
}

struct SpeedPlugin;

impl Plugin for SpeedPlugin {
    fn build(&self, app: &mut App) {
        app.add_plugins(
            ResetComponentPlugin::<Speed>::new(), // Reset modifiers, so speed is back to 10.
        )
        .add_systems(Startup, init_speed)
        .add_systems(
            Update,
            (
                // Modifiers must be applied before the speed can be read.
                apply_modifiers.in_set(StatSystems::Modify),
                read_speed.in_set(StatSystems::Read),
            ),
        );
    }
}

// Implements `reset_modifiers` by passing the call onto `Stat`.
#[derive(StatContainer, Component)]
struct Speed(Stat);

fn init_speed(mut commands: Commands) {
    commands.spawn(Speed(Stat::new(10))); // Set base speed to 10.
}

fn apply_modifiers(mut speeds: Query<&mut Speed>) {
    for mut speed in &mut speeds {
        speed.0 *= 2.0; // Applies a multiplier to the final result.
        speed.0 += 5; // Adds a bonus to the final result.
        // The order does not matter, bonuses are always applied before multipliers.
    }
}

fn read_speed(speeds: Query<&Speed>) {
    for speed in &speeds {
        println!("The current speed is {}.", speed.0.total());
        assert_eq!(speed.0.total(), 30); // (10 + 5) * 2 = 30
    }
}