Rapier context as a Component

bevy_rapier3d/examples/ray_casting3.rs

@@ -76,7 +76,7 @@ pub fn setup_physics(mut commands: Commands) {
 pub fn cast_ray(
     mut commands: Commands,
     windows: Query<&Window, With<PrimaryWindow>>,
-    rapier_context: DefaultRapierContextAccessMut,
+    rapier_context: DefaultRapierContextAccess,
     cameras: Query<(&Camera, &GlobalTransform)>,
 ) {
     let window = windows.single();

src/plugin/context/mod.rs

@@ -375,16 +375,13 @@ impl RapierContext {
         collision_event_writer: &mut EventWriter<CollisionEvent>,
         contact_force_event_writer: &mut EventWriter<ContactForceEvent>,
     ) {
-        for collision_event in self.collision_events_to_send.iter() {
-            collision_event_writer.send(*collision_event);
+        for collision_event in self.collision_events_to_send.drain(..) {
+            collision_event_writer.send(collision_event);
         }
-        self.collision_events_to_send.clear();
 
-        for contact_force_event in self.contact_force_events_to_send.iter() {
-            contact_force_event_writer.send(*contact_force_event);
+        for contact_force_event in self.contact_force_events_to_send.drain(..) {
+            contact_force_event_writer.send(contact_force_event);
         }
-
-        self.contact_force_events_to_send.clear();
     }
 
     /// This method makes sure that the rigid-body positions have been propagated to

src/plugin/context/systemparams/rapier_context_access.rs

@@ -3,14 +3,20 @@ use bevy::prelude::*;
 use std::ops::{Deref, DerefMut};
 
 use super::super::{DefaultRapierContext, RapierContext, RapierContextEntityLink};
-/// Utility [`SystemParam`] to easily access the default world [`RapierContext`] immutably
+/// Utility [`SystemParam`] to easily access the single default [`RapierContext`] immutably.
+///
+/// SAFETY: Dereferencing this struct will panic if its underlying query fails.
+/// See [`RapierContextAccess`] for a safer alternative.
 #[derive(SystemParam)]
 pub struct DefaultRapierContextAccess<'w, 's, T: Component = DefaultRapierContext> {
     rapier_context: Query<'w, 's, &'static RapierContext, With<T>>,
 }
 
 impl<'w, 's, T: Component> DefaultRapierContextAccess<'w, 's, T> {
-    /// Use this method if you only have one world.
+    /// Use this method if you only have one [`RapierContext`].
+    ///
+    /// SAFETY: This method will panic if its underlying query fails.
+    /// See [`RapierContextAccess`] for a safe alternative.
     pub fn single(&'_ self) -> &RapierContext {
         self.rapier_context.single()
     }
@@ -19,12 +25,19 @@ impl<'w, 's, T: Component> DefaultRapierContextAccess<'w, 's, T> {
 impl<'w, 's> Deref for DefaultRapierContextAccess<'w, 's> {
     type Target = RapierContext;
 
+    /// Use this method if you only have one [`RapierContext`].
+    ///
+    /// SAFETY: This method will panic if its underlying query fails.
+    /// See [`RapierContextAccess`] for a safe alternative.
     fn deref(&self) -> &Self::Target {
         self.rapier_context.single()
     }
 }
 
-/// Utility [`SystemParam`] to easily access the default world [`RapierContext`] mutably
+/// Utility [`SystemParam`] to easily access the single default [`RapierContext`] mutably.
+///
+/// SAFETY: Dereferencing this struct will panic if its underlying query fails.
+/// See [`RapierContextAccess`] for a safer alternative.
 #[derive(SystemParam)]
 pub struct DefaultRapierContextAccessMut<'w, 's, T: Component = DefaultRapierContext> {
     rapier_context: Query<'w, 's, &'static mut RapierContext, With<T>>,
@@ -33,12 +46,20 @@ pub struct DefaultRapierContextAccessMut<'w, 's, T: Component = DefaultRapierCon
 impl<'w, 's, T: Component> Deref for DefaultRapierContextAccessMut<'w, 's, T> {
     type Target = RapierContext;
 
+    /// Use this method if you only have one [`RapierContext`].
+    ///
+    /// SAFETY: This method will panic if its underlying query fails.
+    /// See [`RapierContextAccess`] for a safe alternative.
     fn deref(&self) -> &Self::Target {
         self.rapier_context.single()
     }
 }
 
 impl<'w, 's> DerefMut for DefaultRapierContextAccessMut<'w, 's> {
+    /// Use this method if you only have one [`RapierContext`].
+    ///
+    /// SAFETY: This method will panic if its underlying query fails.
+    /// See [`RapierContextAccess`] for a safe alternative.
     fn deref_mut(&mut self) -> &mut Self::Target {
         // TODO: should we cache the result ?
         self.rapier_context.single_mut().into_inner()
@@ -58,11 +79,18 @@ pub struct RapierContextAccess<'w, 's> {
 
 impl<'w, 's> RapierContextAccess<'w, 's> {
     /// Retrieves the rapier context responsible for the entity owning the given [`RapierContextEntityLink`].
-    pub fn context(&self, link: RapierContextEntityLink) -> &'_ RapierContext {
-        self.rapier_context
-            .get(link.0)
+    ///
+    /// SAFETY: This method will panic if its underlying query fails.
+    /// See [`Self::try_context`] for a safe alternative.
+    pub fn context(&self, link: &RapierContextEntityLink) -> &'_ RapierContext {
+        self.try_context(link)
             .expect("RapierContextEntityLink.0 refers to an entity without RapierContext.")
     }
+
+    /// Retrieves the rapier context responsible for the entity owning the given [`RapierContextEntityLink`].
+    pub fn try_context(&self, link: &RapierContextEntityLink) -> Option<&'_ RapierContext> {
+        self.rapier_context.get(link.0).ok()
+    }
 }
 
 impl<'w, 's> Deref for RapierContextAccess<'w, 's> {
@@ -86,40 +114,54 @@ pub struct RapierContextAccessMut<'w, 's> {
 
 impl<'w, 's> RapierContextAccessMut<'w, 's> {
     /// Retrieves the rapier context responsible for the entity owning the given [`RapierContextEntityLink`].
-    pub fn context(&mut self, link: RapierContextEntityLink) -> &'_ mut RapierContext {
-        self.rapier_context
-            .get_mut(link.0)
+    ///
+    /// SAFETY: This method will panic if its underlying query fails.
+    /// See [`Self::try_context`] for a safe alternative.
+    pub fn context(&mut self, link: &RapierContextEntityLink) -> Mut<RapierContext> {
+        self.try_context(link)
             .expect("RapierContextEntityLink.0 refers to an entity without RapierContext.")
-            .into_inner()
+    }
+
+    /// Retrieves the rapier context responsible for the entity owning the given [`RapierContextEntityLink`].
+    pub fn try_context(&mut self, link: &RapierContextEntityLink) -> Option<Mut<RapierContext>> {
+        self.rapier_context.get_mut(link.0).ok()
     }
 
     /// Retrieves the rapier context component on this [`Entity`].
     ///
-    /// Do not call this on a rapier managed entity. given entity should have a [`RapierContext`].
+    /// Calling this method on a rapier managed entity (rigid body, collider, joints...) will fail.
+    /// Given entity should have a [`RapierContext`].
+    ///
+    /// SAFETY: This method will panic if its underlying query fails.
     pub(crate) fn context_from_entity(
         &mut self,
         rapier_context_entity: Entity,
-    ) -> &'_ mut RapierContext {
-        self.rapier_context
-            .get_mut(rapier_context_entity)
-            .unwrap_or_else(|_| panic!("entity {rapier_context_entity} has no RapierContext."))
-            .into_inner()
+    ) -> Mut<RapierContext> {
+        self.try_context_from_entity(rapier_context_entity)
+            .unwrap_or_else(|| panic!("entity {rapier_context_entity} has no RapierContext."))
+    }
+
+    /// Retrieves the rapier context component on this [`Entity`].
+    ///
+    /// Calling this method on a rapier managed entity (rigid body, collider, joints...) will fail.
+    /// Given entity should have a [`RapierContext`].
+    pub fn try_context_from_entity(
+        &mut self,
+        rapier_context_entity: Entity,
+    ) -> Option<Mut<RapierContext>> {
+        self.rapier_context.get_mut(rapier_context_entity).ok()
     }
 }
 
-pub fn try_get_default_context(
+/// Gets the default RapierContext.
+///
+/// SAFETY: Panics if no entity with [`DefaultRapierContext`] exist.
+pub fn get_single_context(
     default_context_access: &Query<Entity, With<DefaultRapierContext>>,
-) -> Option<Entity> {
-    let context_entity = match default_context_access.iter().next() {
-        Some(it) => it,
-        None => {
-            log::error!(
-                "No entity with `DefaultRapierContext` found.\
+) -> Entity {
+    default_context_access.get_single().expect(
+        "No entity with `DefaultRapierContext` found.\
                         Please add a default `RapierContext` or a `RapierContextEntityLink`\
-                        on the new rapier-managed entity."
-            );
-            return None;
-        }
-    };
-    Some(context_entity)
+                        on the new rapier-managed entity.",
+    )
 }

src/plugin/plugin.rs

@@ -109,7 +109,6 @@ where
                     .in_set(RapierTransformPropagateSet),
                 systems::on_add_entity_with_parent,
                 systems::on_change_world,
-                //
                 systems::sync_removals,
                 #[cfg(all(feature = "dim3", feature = "async-collider"))]
                 systems::init_async_scene_colliders,
@@ -118,8 +117,6 @@ where
                 systems::init_rigid_bodies,
                 systems::init_colliders,
                 systems::init_joints,
-                //systems::sync_removals,
-                // Run this here so the following systems do not have a 1 frame delay.
                 systems::apply_scale,
                 systems::apply_collider_user_changes,
                 systems::apply_rigid_body_user_changes,
@@ -246,20 +243,6 @@ where
                     .before(TransformSystem::TransformPropagate),
             );
 
-            // These *must* be in the main schedule currently so that they do not miss events.
-            /*app.add_systems(
-                PostUpdate,
-                (
-                    // Change any worlds needed before doing any calculations
-                    systems::on_add_entity_with_parent,
-                    systems::on_change_world,
-                    // Make sure to remove any dead bodies after changing_worlds but before everything else
-                    // to avoid it deleting something right after adding it
-                    //systems::sync_removals,
-                )
-                    .chain(),
-            );*/
-
             app.add_systems(
                 self.schedule,
                 (
@@ -287,12 +270,15 @@ where
 
 /// Specifies a default configuration for the default `RapierContext`
 ///
-/// If [`None`], no world will be initialized, you are responsible of creating and maintaining
-/// a [`RapierContext`] before creating any rapier entities (rigidbodies, colliders, joints),
-/// and as long as any [`RapierContextEntityLink`] has a reference to its [`RapierContext`].
+/// If [`NoAutomaticRapierContext`],
 #[derive(Resource, Debug, Reflect, Clone)]
 pub enum RapierContextInitialization {
     /// [`RapierPhysicsPlugin`] will not spawn any entity containing [`RapierContext`] automatically.
+    ///
+    /// You are responsible for creating a [`RapierContext`],
+    /// before spawning any rapier entities (rigidbodies, colliders, joints).
+    ///
+    /// You might be interested in adding [`DefaultRapierContext`] to the created world.
     NoAutomaticRapierContext,
     /// [`RapierPhysicsPlugin`] will spawn an entity containing a [`RapierContext`]
     /// automatically during [`PreStartup`], with the [`DefaultRapierContext`] marker component.

src/plugin/systems/character_controller.rs

@@ -39,11 +39,13 @@ pub fn update_character_controls(
         glob_transform,
     ) in character_controllers.iter_mut()
     {
-        let context = context_access.context(*rapier_context_link);
-        let config = config.get(rapier_context_link.0).unwrap();
         if let (Some(raw_controller), Some(translation)) =
             (controller.to_raw(), controller.translation)
         {
+            let config = config
+                .get(rapier_context_link.0)
+                .expect("Could not get [`RapierConfiguration`]");
+            let context = context_access.context(rapier_context_link).into_inner();
             let scaled_custom_shape =
                 controller
                     .custom_shape