cebb553bff
[RENDERED](https://github.com/NiklasEi/bevy/blob/ecs_readme/crates/bevy_ecs/README.md) Since I am trying to learn more about Bevy ECS at the moment, I thought this issue is a perfect fit. This PR adds a readme to the `bevy_ecs` crate containing a minimal running example of stand alone `bevy_ecs`. Unique features like customizable component storage, Resources or change detection are introduced. For each of these features the readme links to an example in a newly created examples directory inside the `bevy_esc` crate. Resolves #2008 Co-authored-by: Carter Anderson <mcanders1@gmail.com>
51 lines
1.4 KiB
Rust
51 lines
1.4 KiB
Rust
use bevy_ecs::prelude::*;
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use rand::Rng;
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use std::ops::Deref;
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// In this example we add a counter resource and increase it's value in one system,
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// while a different system prints the current count to the console.
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fn main() {
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// Create a world
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let mut world = World::new();
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// Add the counter resource
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world.insert_resource(Counter { value: 0 });
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// Create a schedule and a stage
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let mut schedule = Schedule::default();
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let mut update = SystemStage::parallel();
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// Add systems to increase the counter and to print out the current value
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update.add_system(increase_counter.system().label(CounterSystem::Increase));
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update.add_system(print_counter.system().after(CounterSystem::Increase));
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schedule.add_stage("update", update);
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for iteration in 1..=10 {
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println!("Simulating frame {}/10", iteration);
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schedule.run(&mut world);
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}
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}
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// Counter resource to be increased and read by systems
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#[derive(Debug)]
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struct Counter {
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pub value: i32,
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}
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// System label to enforce a run order of our systems
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#[derive(SystemLabel, Debug, Clone, PartialEq, Eq, Hash)]
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enum CounterSystem {
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Increase,
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}
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fn increase_counter(mut counter: ResMut<Counter>) {
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if rand::thread_rng().gen_bool(0.5) {
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counter.value += 1;
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println!(" Increased counter value");
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}
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}
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fn print_counter(counter: Res<Counter>) {
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println!(" {:?}", counter.deref());
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}
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