bevy/examples/animation/gltf_skinned_mesh.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

72 lines
2.6 KiB
Rust

//! Skinned mesh example with mesh and joints data loaded from a glTF file.
//! Example taken from <https://github.com/KhronosGroup/glTF-Tutorials/blob/master/gltfTutorial/gltfTutorial_019_SimpleSkin.md>
use std::f32::consts::*;
use bevy::{pbr::AmbientLight, prelude::*, render::mesh::skinning::SkinnedMesh};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.insert_resource(AmbientLight {
brightness: 1.0,
..default()
})
.add_startup_system(setup)
.add_system(joint_animation)
.run();
}
fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
// Create a camera
commands.spawn(Camera3dBundle {
transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
..default()
});
// Spawn the first scene in `models/SimpleSkin/SimpleSkin.gltf`
commands.spawn(SceneBundle {
scene: asset_server.load("models/SimpleSkin/SimpleSkin.gltf#Scene0"),
..default()
});
}
/// The scene hierarchy currently looks somewhat like this:
///
/// ```ignore
/// <Parent entity>
/// + Mesh node (without `PbrBundle` or `SkinnedMesh` component)
/// + Skinned mesh entity (with `PbrBundle` and `SkinnedMesh` component, created by glTF loader)
/// + First joint
/// + Second joint
/// ```
///
/// In this example, we want to get and animate the second joint.
/// It is similar to the animation defined in `models/SimpleSkin/SimpleSkin.gltf`.
fn joint_animation(
time: Res<Time>,
parent_query: Query<&Parent, With<SkinnedMesh>>,
children_query: Query<&Children>,
mut transform_query: Query<&mut Transform>,
) {
// Iter skinned mesh entity
for skinned_mesh_parent in &parent_query {
// Mesh node is the parent of the skinned mesh entity.
let mesh_node_entity = skinned_mesh_parent.get();
// Get `Children` in the mesh node.
let mesh_node_children = children_query.get(mesh_node_entity).unwrap();
// First joint is the second child of the mesh node.
let first_joint_entity = mesh_node_children[1];
// Get `Children` in the first joint.
let first_joint_children = children_query.get(first_joint_entity).unwrap();
// Second joint is the first child of the first joint.
let second_joint_entity = first_joint_children[0];
// Get `Transform` in the second joint.
let mut second_joint_transform = transform_query.get_mut(second_joint_entity).unwrap();
second_joint_transform.rotation =
Quat::from_rotation_z(FRAC_PI_2 * time.elapsed_seconds().sin());
}
}