Merge pull request bevyengine#28 from blamelessgames/hierarchy-spawning

spawning physics entities using bevy hierarchy

src/physics/systems.rs

@@ -12,33 +12,139 @@ use rapier::geometry::{BroadPhase, ColliderBuilder, ColliderSet, NarrowPhase};
 use rapier::math::Isometry;
 use rapier::pipeline::PhysicsPipeline;
 
-// TODO: right now we only support one collider attached to one body.
-// This should be extanded to multiple bodies.
-// The reason why we build the body and the collider in the same system is
-// because systems run in parallel. This implies that if the collider creation
-// system runs before the body creation system, then it won't be able to create
-// the colliders because the related rigid-body handles don't exist yet. This
-// causes things to be initialized during multiple frames instead of just one.
 /// System responsible for creating a Rapier rigid-body and collider from their
 /// builder resources.
 pub fn create_body_and_collider_system(
     mut commands: Commands,
     mut bodies: ResMut<RigidBodySet>,
     mut colliders: ResMut<ColliderSet>,
     mut entity_maps: ResMut<EntityMaps>,
-    entity: Entity,
-    body_builder: &RigidBodyBuilder,
-    collider_builder: &ColliderBuilder,
+    standalone_body_query: Query<Without<ColliderBuilder, (Entity, &RigidBodyBuilder)>>,
+    body_and_collider_query: Query<(Entity, &RigidBodyBuilder, &ColliderBuilder)>,
+    parented_collider_query: Query<Without<RigidBodyBuilder, (Entity, &Parent, &ColliderBuilder)>>,
 ) {
-    let handle = bodies.insert(body_builder.build());
-    commands.insert_one(entity, RigidBodyHandleComponent::from(handle));
-    commands.remove_one::<RigidBodyBuilder>(entity);
-    entity_maps.bodies.insert(entity, handle);
-
-    let handle = colliders.insert(collider_builder.build(), handle, &mut bodies);
-    commands.insert_one(entity, ColliderHandleComponent::from(handle));
-    commands.remove_one::<ColliderBuilder>(entity);
-    entity_maps.colliders.insert(entity, handle);
+    for (entity, body_builder) in standalone_body_query.iter() {
+        let handle = bodies.insert(body_builder.build());
+        commands.insert_one(entity, RigidBodyHandleComponent::from(handle));
+        commands.remove_one::<RigidBodyBuilder>(entity);
+        entity_maps.bodies.insert(entity, handle);
+    }
+
+    for (entity, body_builder, collider_builder) in body_and_collider_query.iter() {
+        let handle = bodies.insert(body_builder.build());
+        commands.insert_one(entity, RigidBodyHandleComponent::from(handle));
+        commands.remove_one::<RigidBodyBuilder>(entity);
+        entity_maps.bodies.insert(entity, handle);
+
+        let handle = colliders.insert(collider_builder.build(), handle, &mut bodies);
+        commands.insert_one(entity, ColliderHandleComponent::from(handle));
+        commands.remove_one::<ColliderBuilder>(entity);
+        entity_maps.colliders.insert(entity, handle);
+    }
+
+    for (entity, parent, collider_builder) in parented_collider_query.iter() {
+        if let Some(body_handle) = entity_maps.bodies.get(&parent.0) {
+            let handle = colliders.insert(collider_builder.build(), *body_handle, &mut bodies);
+            commands.insert_one(entity, ColliderHandleComponent::from(handle));
+            commands.remove_one::<ColliderBuilder>(entity);
+            entity_maps.colliders.insert(entity, handle);
+        } // warn here? panic here? do nothing?
+    }
+}
+
+#[test]
+fn test_create_body_and_collider_system() {
+    use bevy::ecs::Schedule;
+
+    let mut resources = Resources::default();
+    resources.insert(RigidBodySet::new());
+    resources.insert(ColliderSet::new());
+    resources.insert(EntityMaps::default());
+
+    let mut world = World::new();
+    let body_and_collider_entity =
+        world.spawn((RigidBodyBuilder::new_dynamic(), ColliderBuilder::ball(1.0)));
+
+    let body_only_entity = world.spawn((
+        RigidBodyBuilder::new_static(),
+        Parent(body_and_collider_entity),
+    ));
+
+    let parented_collider_entity_1 =
+        world.spawn((Parent(body_and_collider_entity), ColliderBuilder::ball(0.5)));
+
+    let parented_collider_entity_2 =
+        world.spawn((Parent(body_only_entity), ColliderBuilder::ball(0.25)));
+
+    let mut schedule = Schedule::default();
+    schedule.add_stage("physics_test");
+    schedule.add_system_to_stage("physics_test", create_body_and_collider_system.system());
+    schedule.run(&mut world, &mut resources);
+
+    let body_set = resources.get::<RigidBodySet>().unwrap();
+    let collider_set = resources.get::<ColliderSet>().unwrap();
+    let entity_maps = resources.get::<EntityMaps>().unwrap();
+
+    // body attached alongside collider
+    let attached_body_handle = world
+        .get::<RigidBodyHandleComponent>(body_and_collider_entity)
+        .unwrap()
+        .handle();
+    assert_eq!(
+        entity_maps.bodies[&body_and_collider_entity],
+        attached_body_handle
+    );
+    assert!(body_set.get(attached_body_handle).unwrap().is_dynamic());
+
+    // collider attached from same entity
+    let collider_handle = world
+        .get::<ColliderHandleComponent>(body_and_collider_entity)
+        .unwrap()
+        .handle();
+    assert_eq!(
+        entity_maps.colliders[&body_and_collider_entity],
+        collider_handle
+    );
+    let collider = collider_set.get(collider_handle).unwrap();
+    assert_eq!(attached_body_handle, collider.parent());
+    assert_eq!(collider.shape().as_ball().unwrap().radius, 1.0);
+
+    // collider attached to child entity of body with collider
+    let collider_handle = world
+        .get::<ColliderHandleComponent>(parented_collider_entity_1)
+        .unwrap()
+        .handle();
+    assert_eq!(
+        entity_maps.colliders[&parented_collider_entity_1],
+        collider_handle
+    );
+    let collider = collider_set.get(collider_handle).unwrap();
+    assert_eq!(attached_body_handle, collider.parent());
+    assert_eq!(collider.shape().as_ball().unwrap().radius, 0.5);
+
+    // standalone body with no collider, jointed to the attached body
+    let standalone_body_handle = world
+        .get::<RigidBodyHandleComponent>(body_only_entity)
+        .unwrap()
+        .handle();
+    assert_eq!(
+        entity_maps.bodies[&body_only_entity],
+        standalone_body_handle
+    );
+    assert!(body_set.get(standalone_body_handle).unwrap().is_static());
+
+    // collider attached to child entity of standlone body
+    let collider_handle = world
+        .get::<ColliderHandleComponent>(parented_collider_entity_2)
+        .unwrap()
+        .handle();
+    assert_eq!(
+        entity_maps.colliders[&parented_collider_entity_2],
+        collider_handle
+    );
+    let collider = collider_set.get(collider_handle).unwrap();
+    assert_eq!(standalone_body_handle, collider.parent());
+    assert_eq!(collider.shape().as_ball().unwrap().radius, 0.25);
 }
 
 /// System responsible for creating Rapier joints from their builder resources.