multiple worlds working + example

example from dimforge#328

Co-authored-by: Anthony Tornetta <25857049+AnthonyTornetta@users.noreply.github.com>

Author: ThierryBerger

CHANGELOG.md

@@ -7,11 +7,10 @@
 - `RapierContext` is now a `Component`
   - Rapier now supports multiple worlds.
   - Migration guide: 
-    - `ResMut<mut RapierContext>` -> `RapierContextAccessMut`
-    - `Res<RapierContext>` -> `Query<&RapierContext>`
-    - `ResMut<RapierConfiguration>` -> `Query<&mut RapierConfiguration>`
-    - `Res<RapierConfiguration>` -> `Query<&RapierConfiguration>`
-    - you can reach out for the underlying configuration via .single
+    - `ResMut<mut RapierContext>` -> `DefaultRapierContextAccessMut`
+    - `Res<RapierContext>` -> `DefaultRapierContextAccess`
+    - `ResMut<RapierConfiguration>` -> `DefaultRapierConfigurationMut`
+    - `Res<RapierConfiguration>` -> `DefaultRapierConfiguration`
 
 ## v0.27.0-rc.1 (18 June 2024)
 

bevy_rapier3d/examples/multi_world3.rs

@@ -0,0 +1,117 @@
+use bevy::prelude::*;
+use bevy_rapier3d::prelude::*;
+
+const N_WORLDS: usize = 2;
+
+fn main() {
+    App::new()
+        .insert_resource(ClearColor(Color::rgb(
+            0xF9 as f32 / 255.0,
+            0xF9 as f32 / 255.0,
+            0xFF as f32 / 255.0,
+        )))
+        .add_plugins((
+            DefaultPlugins,
+            RapierPhysicsPlugin::<NoUserData>::default().with_default_world(None),
+            RapierDebugRenderPlugin::default(),
+        ))
+        .add_systems(
+            Startup,
+            ((create_worlds, setup_physics).chain(), setup_graphics),
+        )
+        .add_systems(Update, move_platforms)
+        // .add_systems(Update, change_world)
+        // .add_systems(Update, despawn_last)
+        .run();
+}
+
+fn create_worlds(mut commands: Commands) {
+    for i in 0..N_WORLDS {
+        commands.spawn((RapierContext::default(), WorldId(i)));
+    }
+}
+
+fn setup_graphics(mut commands: Commands) {
+    commands.spawn(Camera3dBundle {
+        transform: Transform::from_xyz(0.0, 3.0, -10.0)
+            .looking_at(Vec3::new(0.0, 0.0, 0.0), Vec3::Y),
+        ..Default::default()
+    });
+}
+
+#[derive(Component)]
+pub struct WorldId(pub usize);
+
+#[derive(Component)]
+struct Platform {
+    starting_y: f32,
+}
+
+fn move_platforms(time: Res<Time>, mut query: Query<(&mut Transform, &Platform)>) {
+    for (mut transform, platform) in query.iter_mut() {
+        transform.translation.y = platform.starting_y + -time.elapsed_seconds().sin();
+    }
+}
+
+/// Demonstrates despawning an entity removing it from its world
+// fn despawn_last(query: Query<(&PhysicsWorld, Entity)>, mut commands: Commands) {
+//     for (bw, entity) in query.iter() {
+//         if bw.world_id == N_WORLDS - 1 {
+//             commands.entity(entity).despawn_recursive();
+//         }
+//     }
+// }
+
+/// Demonstrates how easy it is to move one entity to another world.
+// fn change_world(mut query: Query<&mut PhysicsWorld>) {
+//     for mut bw in query.iter_mut() {
+//         if bw.world_id == 1 {
+//             bw.world_id = 0;
+//         }
+//     }
+// }
+
+pub fn setup_physics(
+    context: Query<(Entity, &WorldId), With<RapierContext>>,
+    mut commands: Commands,
+) {
+    for (context_entity, id) in context.iter() {
+        let id = id.0;
+
+        let color = [
+            Hsla::hsl(220.0, 1.0, 0.3),
+            Hsla::hsl(180.0, 1.0, 0.3),
+            Hsla::hsl(260.0, 1.0, 0.7),
+        ][id % 3];
+
+        /*
+         * Ground
+         */
+        let ground_size = 5.1;
+        let ground_height = 0.1;
+
+        let starting_y = (id as f32) * -0.5 - ground_height;
+
+        let mut platforms = commands.spawn((
+            TransformBundle::from(Transform::from_xyz(0.0, starting_y, 0.0)),
+            Collider::cuboid(ground_size, ground_height, ground_size),
+            ColliderDebugColor(color),
+            RapierContextEntityLink(context_entity),
+        ));
+        if id == 1 {
+            platforms.insert(Platform { starting_y });
+        }
+
+        /*
+         * Create the cube
+         */
+
+        commands.spawn((
+            TransformBundle::from(Transform::from_xyz(0.0, 1.0 + id as f32 * 5.0, 0.0)),
+            RigidBody::Dynamic,
+            Collider::cuboid(0.5, 0.5, 0.5),
+            ColliderDebugColor(color),
+            RapierContextEntityLink(context_entity),
+        ));
+    }
+}

src/plugin/context/systemparams/mod.rs

@@ -0,0 +1,12 @@
+mod rapier_context_access;
+
+use bevy::{ecs::query::QueryData, prelude::Entity};
+pub use rapier_context_access::*;
+
+use super::RapierContextEntityLink;
+
+#[derive(QueryData)]
+pub struct RapierEntity {
+    pub entity: Entity,
+    pub rapier_context_link: &'static RapierContextEntityLink,
+}

src/plugin/context/systemparams.rs …xt/systemparams/rapier_context_access.rssrc/plugin/context/systemparams.rs renamed to src/plugin/context/systemparams/rapier_context_access.rs src/plugin/context/systemparams.rs renamed to src/plugin/context/systemparams/rapier_context_access.rs

@@ -2,8 +2,7 @@ use bevy::ecs::system::SystemParam;
 use bevy::prelude::*;
 use std::ops::{Deref, DerefMut};
 
-use super::{DefaultRapierContext, RapierContext, RapierContextEntityLink};
-
+use super::super::{DefaultRapierContext, RapierContext, RapierContextEntityLink};
 /// Utility [`SystemParam`] to easily access the default world [`RapierContext`] immutably
 #[derive(SystemParam)]
 pub struct DefaultRapierContextAccess<'w, 's> {
@@ -50,25 +49,14 @@ impl<'w, 's> DerefMut for DefaultRapierContextAccessMut<'w, 's> {
 #[derive(SystemParam)]
 pub struct RapierContextAccess<'w, 's> {
     rapier_context: Query<'w, 's, &'static RapierContext>,
-    rapier_context_link: Query<'w, 's, &'static RapierContextEntityLink>,
 }
 
 impl<'w, 's> RapierContextAccess<'w, 's> {
-    pub fn link(&self, entity: Entity) -> &RapierContextEntityLink {
-        self.rapier_context_link
-            .get(entity)
-            .expect("RapierContextAccess.link called on an entity without RapierContextEntityLink.")
-    }
-    pub fn follow_link(&self, link: RapierContextEntityLink) -> &'_ RapierContext {
+    pub fn context(&self, link: RapierContextEntityLink) -> &'_ RapierContext {
         self.rapier_context
             .get(link.0)
             .expect("RapierContextEntityLink.0 refers to an entity without RapierContext.")
     }
-
-    pub fn context(&self, entity: Entity) -> &'_ RapierContext {
-        let context_link = self.link(entity);
-        self.follow_link(*context_link)
-    }
 }
 
 impl<'w, 's> Deref for RapierContextAccess<'w, 's> {
@@ -83,35 +71,24 @@ impl<'w, 's> Deref for RapierContextAccess<'w, 's> {
 #[derive(SystemParam)]
 pub struct RapierContextAccessMut<'w, 's> {
     pub rapier_context: Query<'w, 's, &'static mut RapierContext>,
-    pub rapier_context_link: Query<'w, 's, &'static RapierContextEntityLink>,
 }
 
 impl<'w, 's> RapierContextAccessMut<'w, 's> {
-    pub fn link(&self, entity: Entity) -> &RapierContextEntityLink {
-        self.rapier_context_link.get(entity).expect(
-            "RapierContextAccessMut.link called on an entity without RapierContextEntityLink.",
-        )
-    }
-    pub fn follow_link(&mut self, link: RapierContextEntityLink) -> &'_ mut RapierContext {
+    pub fn context(&mut self, link: RapierContextEntityLink) -> &'_ mut RapierContext {
         self.rapier_context
             .get_mut(link.0)
             .expect("RapierContextEntityLink.0 refers to an entity without RapierContext.")
             .into_inner()
     }
-
-    pub fn context(&mut self, entity: Entity) -> &'_ mut RapierContext {
-        let context_link = self.link(entity);
-        self.follow_link(*context_link)
-    }
 }
 
 pub fn try_retrieve_context<'a>(
     link: Option<&RapierContextEntityLink>,
-    context: &Query<(Entity, &mut RapierContext)>,
+    context: &Query<Entity, With<RapierContext>>,
 ) -> Result<Entity, Entity> {
     link.map_or_else(
         || {
-            let context_entity = context.iter().next().unwrap().0;
+            let context_entity = context.iter().next().unwrap();
             Err(context_entity)
         },
         |link| Ok(link.0),

src/plugin/mod.rs

@@ -4,7 +4,7 @@ pub use self::context::{
         DefaultRapierContextAccess, DefaultRapierContextAccessMut, RapierContextAccess,
         RapierContextAccessMut,
     },
-    RapierContext,
+    RapierContext, RapierContextEntityLink,
 };
 pub use self::plugin::{NoUserData, PhysicsSet, RapierPhysicsPlugin, RapierTransformPropagateSet};
 

src/plugin/plugin.rs

@@ -44,6 +44,18 @@ where
         });
         self
     }
+    /// 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`].
+    pub fn with_default_world(
+        mut self,
+        default_world_initialization: Option<RapierContextInitialization>,
+    ) -> Self {
+        self.default_world_setup = default_world_initialization;
+        self
+    }
 
     /// Specifies whether the plugin should setup each of its [`PhysicsStages`]
     /// (`true`), or if the user will set them up later (`false`).
@@ -244,6 +256,7 @@ where
     }
 }
 
+#[derive(Resource)]
 pub struct RapierContextInitialization {
     pub length_unit: f32,
 }

src/plugin/systems/character_controller.rs

@@ -1,6 +1,7 @@
 use crate::control::CharacterCollision;
 use crate::dynamics::RapierRigidBodyHandle;
 use crate::geometry::RapierColliderHandle;
+use crate::plugin::context::RapierContextEntityLink;
 use crate::plugin::RapierConfiguration;
 use crate::plugin::RapierContextAccessMut;
 use crate::prelude::KinematicCharacterController;
@@ -19,6 +20,7 @@ pub fn update_character_controls(
     mut context_access: RapierContextAccessMut,
     mut character_controllers: Query<(
         Entity,
+        &RapierContextEntityLink,
         &mut KinematicCharacterController,
         Option<&mut KinematicCharacterControllerOutput>,
         Option<&RapierColliderHandle>,
@@ -27,12 +29,18 @@ pub fn update_character_controls(
     )>,
     mut transforms: Query<&mut Transform>,
 ) {
-    for (entity, mut controller, output, collider_handle, body_handle, glob_transform) in
-        character_controllers.iter_mut()
+    for (
+        entity,
+        rapier_context_link,
+        mut controller,
+        output,
+        collider_handle,
+        body_handle,
+        glob_transform,
+    ) in character_controllers.iter_mut()
     {
-        let link = *context_access.link(entity);
-        let context = context_access.follow_link(link);
-        let config = config.get(link.0).unwrap();
+        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)
         {