Allow interpolation of scales

src/collision/collider/backend.rs

@@ -4,7 +4,7 @@
 
 use std::marker::PhantomData;
 
-use crate::{broad_phase::BroadPhaseSet, prelude::*, prepare::PrepareSet};
+use crate::{broad_phase::BroadPhaseSet, prelude::*, prepare::PrepareSet, sync::SyncConfig};
 #[cfg(all(feature = "bevy_scene", feature = "default-collider"))]
 use bevy::scene::SceneInstance;
 use bevy::{
@@ -95,9 +95,53 @@ impl<C: ScalableCollider> Plugin for ColliderBackendPlugin<C> {
 
  // Initialize missing components for colliders.
  hooks.on_add(|mut world, entity, _| {
- let entity_ref = world.entity(entity);
+ let existing_global_transform = world
+ .entity(entity)
+ .get::<GlobalTransform>()
+ .copied()
+ .unwrap_or_default();
+ let global_transform = if existing_global_transform != GlobalTransform::IDENTITY {
+ // This collider was built deferred, probably via `ColliderConstructor`.
+ existing_global_transform
+ } else {
+ // This collider *may* have been `spawn`ed directly on a new entity.
+ // As such, its global transform is not yet available.
+ // You may notice that this will fail if the hierarchy's scale was updated in this
+ // frame. Remember that `GlobalTransform` is not updated in between fixed updates.
+ // But this is fine, as `update_collider_scale` will be updated in the next fixed update anyway.
+ // The reason why we care about initializing this scale here is for those users that opted out of
+ // `update_collider_scale` in order to do their own interpolation, which implies that they won't touch
+ // the `Transform` component before the collider is initialized, which in turn means that it will
+ // always be initialized with the correct `GlobalTransform`.
+ let parent_global_transform = world
+ .entity(entity)
+ .get::<Parent>()
+ .and_then(|parent| world.entity(parent.get()).get::<GlobalTransform>().copied())
+ .unwrap_or_default();
+ let transform = world
+ .entity(entity)
+ .get::<Transform>()
+ .copied()
+ .unwrap_or_default();
+ parent_global_transform * transform
+ };
+
+ let scale = global_transform.compute_transform().scale;
+ #[cfg(feature = "2d")]
+ let scale = scale.xy();
+
+ // Make sure the collider is initialized with the correct scale.
+ // This overwrites the scale set by the constructor, but that one is
+ // meant to be only changed after initialization.
+ world
+ .entity_mut(entity)
+ .get_mut::<C>()
+ .unwrap()
+ .set_scale(scale.adjust_precision(), 10);
 
+ let entity_ref = world.entity(entity);
  let collider = entity_ref.get::<C>().unwrap();
+
  let aabb = entity_ref
  .get::<ColliderAabb>()
  .copied()
@@ -612,20 +656,22 @@ pub fn update_collider_scale<C: ScalableCollider>(
  // Child colliders
  Query<(&ColliderTransform, &mut C), (With<Parent>, Changed<ColliderTransform>)>,
  )>,
+ sync_config: Res<SyncConfig>,
 ) {
- // Update collider scale for root bodies
- for (transform, mut collider) in &mut colliders.p0() {
- #[cfg(feature = "2d")]
- let scale = transform.scale.truncate().adjust_precision();
- #[cfg(feature = "3d")]
- let scale = transform.scale.adjust_precision();
- if scale != collider.scale() {
- // TODO: Support configurable subdivision count for shapes that
- // can't be represented without approximations after scaling.
- collider.set_scale(scale, 10);
+ if sync_config.transform_to_collider_scale {
+ // Update collider scale for root bodies
+ for (transform, mut collider) in &mut colliders.p0() {
+ #[cfg(feature = "2d")]
+ let scale = transform.scale.truncate().adjust_precision();
+ #[cfg(feature = "3d")]
+ let scale = transform.scale.adjust_precision();
+ if scale != collider.scale() {
+ // TODO: Support configurable subdivision count for shapes that
+ // can't be represented without approximations after scaling.
+ collider.set_scale(scale, 10);
+ }
  }
  }
-
  // Update collider scale for child colliders
  for (collider_transform, mut collider) in &mut colliders.p1() {
  if collider_transform.scale != collider.scale() {

src/prepare.rs

@@ -4,7 +4,7 @@
 
 #![allow(clippy::type_complexity)]
 
-use crate::prelude::*;
+use crate::{prelude::*, sync::SyncConfig};
 use bevy::{
  ecs::{
  intern::Interned,
@@ -77,6 +77,8 @@ pub enum PrepareSet {
 
 impl Plugin for PreparePlugin {
  fn build(&self, app: &mut App) {
+ app.init_resource::<SyncConfig>()
+ .register_type::<SyncConfig>();
  app.configure_sets(
  self.schedule,
  (

src/sync/mod.rs

@@ -143,22 +143,32 @@ impl Plugin for SyncPlugin {
  }
 }
 
-/// Configures what physics data is synchronized by the [`SyncPlugin`] and how.
+/// Configures what physics data is synchronized by the [`SyncPlugin`] and [`PreparePlugin`] and how.
 #[derive(Resource, Reflect, Clone, Debug, PartialEq, Eq)]
 #[reflect(Resource)]
 pub struct SyncConfig {
  /// Updates transforms based on [`Position`] and [`Rotation`] changes. Defaults to true.
+ ///
+ /// This operation is run in [`SyncSet::PositionToTransform`].
  pub position_to_transform: bool,
  /// Updates [`Position`] and [`Rotation`] based on transform changes,
- /// allowing you to move bodies using `Transform`. Defaults to true.
+ /// allowing you to move bodies using [`Transform`]. Defaults to true.
+ ///
+ /// This operation is run in [`SyncSet::TransformToPosition`].
  pub transform_to_position: bool,
+ /// Updates [`Collider::scale()`] based on transform changes,
+ /// allowing you to scale colliders using [`Transform`]. Defaults to true.
+ ///
+ /// This operation is run in [`PrepareSet::Finalize`]
+ pub transform_to_collider_scale: bool,
 }
 
 impl Default for SyncConfig {
  fn default() -> Self {
  SyncConfig {
  position_to_transform: true,
  transform_to_position: true,
+ transform_to_collider_scale: true,
  }
  }
 }