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>
40 lines
1.4 KiB
Rust
40 lines
1.4 KiB
Rust
use bevy_ecs::{
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component::{ComponentDescriptor, StorageType},
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prelude::*,
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};
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// This example shows how to configure the storage of Components.
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// A system demonstrates that querying for components is independent of their storage type.
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fn main() {
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let mut world = World::new();
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// Store components of type `i32` in a Sparse set
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world
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.register_component(ComponentDescriptor::new::<i32>(StorageType::SparseSet))
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.expect("The component of type i32 is already in use");
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// Components of type i32 will have the above configured Sparse set storage,
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// while f64 components will have the default table storage
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world.spawn().insert(1).insert(0.1);
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world.spawn().insert(2);
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world.spawn().insert(0.2);
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// Setup a schedule and stage to add a system querying for the just spawned entities
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let mut schedule = Schedule::default();
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let mut update = SystemStage::parallel();
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update.add_system(query_entities.system());
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schedule.add_stage("update", update);
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schedule.run(&mut world);
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}
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// The storage type does not matter for how to query in systems
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fn query_entities(entities_with_i32: Query<&i32>, entities_with_f64: Query<&f64>) {
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for value in entities_with_i32.iter() {
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println!("Got entity with i32: {}", value);
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}
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for value in entities_with_f64.iter() {
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println!("Got entity with f64: {}", value);
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}
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}
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