bevy/examples/3d/load_gltf.rs
Carter Anderson dcc03724a5 Base Sets (#7466)
# Objective

NOTE: This depends on #7267 and should not be merged until #7267 is merged. If you are reviewing this before that is merged, I highly recommend viewing the Base Sets commit instead of trying to find my changes amongst those from #7267.

"Default sets" as described by the [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) have some [unfortunate consequences](https://github.com/bevyengine/bevy/discussions/7365).

## Solution

This adds "base sets" as a variant of `SystemSet`:

A set is a "base set" if `SystemSet::is_base` returns `true`. Typically this will be opted-in to using the `SystemSet` derive:

```rust
#[derive(SystemSet, Clone, Hash, Debug, PartialEq, Eq)]
#[system_set(base)]
enum MyBaseSet {
  A,
  B,
}
``` 

**Base sets are exclusive**: a system can belong to at most one "base set". Adding a system to more than one will result in an error. When possible we fail immediately during system-config-time with a nice file + line number. For the more nested graph-ey cases, this will fail at the final schedule build. 

**Base sets cannot belong to other sets**: this is where the word "base" comes from

Systems and Sets can only be added to base sets using `in_base_set`. Calling `in_set` with a base set will fail. As will calling `in_base_set` with a normal set.

```rust
app.add_system(foo.in_base_set(MyBaseSet::A))
       // X must be a normal set ... base sets cannot be added to base sets
       .configure_set(X.in_base_set(MyBaseSet::A))
```

Base sets can still be configured like normal sets:

```rust
app.add_system(MyBaseSet::B.after(MyBaseSet::Ap))
``` 

The primary use case for base sets is enabling a "default base set":

```rust
schedule.set_default_base_set(CoreSet::Update)
  // this will belong to CoreSet::Update by default
  .add_system(foo)
  // this will override the default base set with PostUpdate
  .add_system(bar.in_base_set(CoreSet::PostUpdate))
```

This allows us to build apis that work by default in the standard Bevy style. This is a rough analog to the "default stage" model, but it use the new "stageless sets" model instead, with all of the ordering flexibility (including exclusive systems) that it provides.

---

## Changelog

- Added "base sets" and ported CoreSet to use them.

## Migration Guide

TODO
2023-02-06 03:10:08 +00:00

64 lines
1.8 KiB
Rust

//! Loads and renders a glTF file as a scene.
use std::f32::consts::*;
use bevy::{
pbr::{CascadeShadowConfigBuilder, DirectionalLightShadowMap},
prelude::*,
};
fn main() {
App::new()
.insert_resource(AmbientLight {
color: Color::WHITE,
brightness: 1.0 / 5.0f32,
})
.insert_resource(DirectionalLightShadowMap { size: 4096 })
.add_plugins(DefaultPlugins)
.add_startup_system(setup)
.add_system(animate_light_direction)
.run();
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(0.7, 0.7, 1.0).looking_at(Vec3::new(0.0, 0.3, 0.0), Vec3::Y),
..default()
});
commands.spawn(DirectionalLightBundle {
directional_light: DirectionalLight {
shadows_enabled: true,
..default()
},
// This is a relatively small scene, so use tighter shadow
// cascade bounds than the default for better quality.
// We also adjusted the shadow map to be larger since we're
// only using a single cascade.
cascade_shadow_config: CascadeShadowConfigBuilder {
num_cascades: 1,
maximum_distance: 1.6,
..default()
}
.into(),
..default()
});
commands.spawn(SceneBundle {
scene: asset_server.load("models/FlightHelmet/FlightHelmet.gltf#Scene0"),
..default()
});
}
fn animate_light_direction(
time: Res<Time>,
mut query: Query<&mut Transform, With<DirectionalLight>>,
) {
for mut transform in &mut query {
transform.rotation = Quat::from_euler(
EulerRot::ZYX,
0.0,
time.elapsed_seconds() * PI / 5.0,
-FRAC_PI_4,
);
}
}