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use crate::components::{GlobalTransform, Transform};
use bevy_ecs::{
change_detection::Ref,
prelude::{Changed, DetectChanges, Entity, Query, With, Without},
};
use bevy_hierarchy::{Children, Parent};
pub fn sync_simple_transforms(
mut query: Query<
(&Transform, &mut GlobalTransform),
(Changed<Transform>, Without<Parent>, Without<Children>),
>,
) {
query
.par_iter_mut()
.for_each_mut(|(transform, mut global_transform)| {
*global_transform = GlobalTransform::from(*transform);
});
}
pub fn propagate_transforms(
mut root_query: Query<
(Entity, &Children, Ref<Transform>, &mut GlobalTransform),
Without<Parent>,
>,
transform_query: Query<(Ref<Transform>, &mut GlobalTransform, Option<&Children>), With<Parent>>,
parent_query: Query<(Entity, Ref<Parent>)>,
) {
root_query.par_iter_mut().for_each_mut(
|(entity, children, transform, mut global_transform)| {
let changed = transform.is_changed();
if changed {
*global_transform = GlobalTransform::from(*transform);
}
for (child, actual_parent) in parent_query.iter_many(children) {
assert_eq!(
actual_parent.get(), entity,
"Malformed hierarchy. This probably means that your hierarchy has been improperly maintained, or contains a cycle"
);
unsafe {
propagate_recursive(
&global_transform,
&transform_query,
&parent_query,
child,
changed || actual_parent.is_changed(),
);
}
}
},
);
}
unsafe fn propagate_recursive(
parent: &GlobalTransform,
transform_query: &Query<
(Ref<Transform>, &mut GlobalTransform, Option<&Children>),
With<Parent>,
>,
parent_query: &Query<(Entity, Ref<Parent>)>,
entity: Entity,
mut changed: bool,
) {
let (global_matrix, children) = {
let Ok((transform, mut global_transform, children)) =
(unsafe { transform_query.get_unchecked(entity) }) else {
return;
};
changed |= transform.is_changed();
if changed {
*global_transform = parent.mul_transform(*transform);
}
(*global_transform, children)
};
let Some(children) = children else { return };
for (child, actual_parent) in parent_query.iter_many(children) {
assert_eq!(
actual_parent.get(), entity,
"Malformed hierarchy. This probably means that your hierarchy has been improperly maintained, or contains a cycle"
);
unsafe {
propagate_recursive(
&global_matrix,
transform_query,
parent_query,
child,
changed || actual_parent.is_changed(),
);
}
}
}
#[cfg(test)]
mod test {
use bevy_app::prelude::*;
use bevy_ecs::prelude::*;
use bevy_ecs::system::CommandQueue;
use bevy_math::vec3;
use bevy_tasks::{ComputeTaskPool, TaskPool};
use crate::components::{GlobalTransform, Transform};
use crate::systems::*;
use crate::TransformBundle;
use bevy_hierarchy::{BuildChildren, BuildWorldChildren, Children, Parent};
#[test]
fn did_propagate() {
ComputeTaskPool::init(TaskPool::default);
let mut world = World::default();
let mut schedule = Schedule::new();
schedule.add_system(sync_simple_transforms);
schedule.add_system(propagate_transforms);
world.spawn(TransformBundle::from(Transform::from_xyz(1.0, 0.0, 0.0)));
let mut children = Vec::new();
world
.spawn(TransformBundle::from(Transform::from_xyz(1.0, 0.0, 0.0)))
.with_children(|parent| {
children.push(
parent
.spawn(TransformBundle::from(Transform::from_xyz(0.0, 2.0, 0.)))
.id(),
);
children.push(
parent
.spawn(TransformBundle::from(Transform::from_xyz(0.0, 0.0, 3.)))
.id(),
);
});
schedule.run(&mut world);
assert_eq!(
*world.get::<GlobalTransform>(children[0]).unwrap(),
GlobalTransform::from_xyz(1.0, 0.0, 0.0) * Transform::from_xyz(0.0, 2.0, 0.0)
);
assert_eq!(
*world.get::<GlobalTransform>(children[1]).unwrap(),
GlobalTransform::from_xyz(1.0, 0.0, 0.0) * Transform::from_xyz(0.0, 0.0, 3.0)
);
}
#[test]
fn did_propagate_command_buffer() {
let mut world = World::default();
let mut schedule = Schedule::new();
schedule.add_system(sync_simple_transforms);
schedule.add_system(propagate_transforms);
let mut queue = CommandQueue::default();
let mut commands = Commands::new(&mut queue, &world);
let mut children = Vec::new();
commands
.spawn(TransformBundle::from(Transform::from_xyz(1.0, 0.0, 0.0)))
.with_children(|parent| {
children.push(
parent
.spawn(TransformBundle::from(Transform::from_xyz(0.0, 2.0, 0.0)))
.id(),
);
children.push(
parent
.spawn(TransformBundle::from(Transform::from_xyz(0.0, 0.0, 3.0)))
.id(),
);
});
queue.apply(&mut world);
schedule.run(&mut world);
assert_eq!(
*world.get::<GlobalTransform>(children[0]).unwrap(),
GlobalTransform::from_xyz(1.0, 0.0, 0.0) * Transform::from_xyz(0.0, 2.0, 0.0)
);
assert_eq!(
*world.get::<GlobalTransform>(children[1]).unwrap(),
GlobalTransform::from_xyz(1.0, 0.0, 0.0) * Transform::from_xyz(0.0, 0.0, 3.0)
);
}
#[test]
fn correct_children() {
ComputeTaskPool::init(TaskPool::default);
let mut world = World::default();
let mut schedule = Schedule::new();
schedule.add_system(sync_simple_transforms);
schedule.add_system(propagate_transforms);
let mut children = Vec::new();
let parent = {
let mut command_queue = CommandQueue::default();
let mut commands = Commands::new(&mut command_queue, &world);
let parent = commands.spawn(Transform::from_xyz(1.0, 0.0, 0.0)).id();
commands.entity(parent).with_children(|parent| {
children.push(parent.spawn(Transform::from_xyz(0.0, 2.0, 0.0)).id());
children.push(parent.spawn(Transform::from_xyz(0.0, 3.0, 0.0)).id());
});
command_queue.apply(&mut world);
schedule.run(&mut world);
parent
};
assert_eq!(
world
.get::<Children>(parent)
.unwrap()
.iter()
.cloned()
.collect::<Vec<_>>(),
children,
);
{
let mut command_queue = CommandQueue::default();
let mut commands = Commands::new(&mut command_queue, &world);
commands.entity(children[1]).add_child(children[0]);
command_queue.apply(&mut world);
schedule.run(&mut world);
}
assert_eq!(
world
.get::<Children>(parent)
.unwrap()
.iter()
.cloned()
.collect::<Vec<_>>(),
vec![children[1]]
);
assert_eq!(
world
.get::<Children>(children[1])
.unwrap()
.iter()
.cloned()
.collect::<Vec<_>>(),
vec![children[0]]
);
assert!(world.despawn(children[0]));
schedule.run(&mut world);
assert_eq!(
world
.get::<Children>(parent)
.unwrap()
.iter()
.cloned()
.collect::<Vec<_>>(),
vec![children[1]]
);
}
#[test]
fn correct_transforms_when_no_children() {
let mut app = App::new();
ComputeTaskPool::init(TaskPool::default);
app.add_system(sync_simple_transforms);
app.add_system(propagate_transforms);
let translation = vec3(1.0, 0.0, 0.0);
let mut child = Entity::from_raw(0);
let mut grandchild = Entity::from_raw(1);
let parent = app
.world
.spawn((
Transform::from_translation(translation),
GlobalTransform::IDENTITY,
))
.with_children(|builder| {
child = builder
.spawn(TransformBundle::IDENTITY)
.with_children(|builder| {
grandchild = builder.spawn(TransformBundle::IDENTITY).id();
})
.id();
})
.id();
app.update();
assert_eq!(&**app.world.get::<Children>(parent).unwrap(), &[child]);
assert_eq!(&**app.world.get::<Children>(child).unwrap(), &[grandchild]);
app.update();
let mut state = app.world.query::<&GlobalTransform>();
for global in state.iter(&app.world) {
assert_eq!(global, &GlobalTransform::from_translation(translation));
}
}
#[test]
#[should_panic]
fn panic_when_hierarchy_cycle() {
ComputeTaskPool::init(TaskPool::default);
let mut temp = World::new();
let mut app = App::new();
app.add_system(propagate_transforms)
.add_system(sync_simple_transforms);
fn setup_world(world: &mut World) -> (Entity, Entity) {
let mut grandchild = Entity::from_raw(0);
let child = world
.spawn(TransformBundle::IDENTITY)
.with_children(|builder| {
grandchild = builder.spawn(TransformBundle::IDENTITY).id();
})
.id();
(child, grandchild)
}
let (temp_child, temp_grandchild) = setup_world(&mut temp);
let (child, grandchild) = setup_world(&mut app.world);
assert_eq!(temp_child, child);
assert_eq!(temp_grandchild, grandchild);
app.world
.spawn(TransformBundle::IDENTITY)
.push_children(&[child]);
std::mem::swap(
&mut *app.world.get_mut::<Parent>(child).unwrap(),
&mut *temp.get_mut::<Parent>(grandchild).unwrap(),
);
app.update();
}
}