feat!: Implemented CollisionEvent trigger

- Added integration tests
- Replaced GlobalTransform with Transform in collision math
- Fixed doc lint
- collider_detects_different_groups test does not pass

src/lib.rs

@@ -1,29 +1,29 @@
+#![warn(missing_docs)]
+
+// TODO: add more precise crate documentation
+//! Simple 2D collision system, inspired by Godot Engine.
+
 use bevy::math::bounding::IntersectsVolume;
-#[warn(missing_docs)]
 
 use bevy::{math::bounding::{Aabb2d, BoundingCircle}, prelude::*};
 
-// TODO: add more precise crate documentation
+#[derive(Component, PartialEq, Debug)]
-// TODO: implement event emitting on collision
-/// Simple 2D collision system, inspired by Godot Engine.
-
-#[derive(Component)]
 /// Enum of available shapes
 pub enum CollisionShape {
     /// Rectangle shape
     Aabb {
-        /// The shape itself, tied to **global** position
+        /// The shape itself, tied to [`Transform`]
         shape: Aabb2d,
-        /// Start offset, used to calculate global position.
+        /// Start offset, used to calculate current position inside shape.
         offset: Vec2,
         /// Size of the shape, used to calculate global position.
         size: Vec2,
     },
     /// Circle shape
     Circle {
-        /// The shape itself, tied to **global** position
+        /// The shape itself, tied to [`Transform`]
         shape: BoundingCircle,
-        /// Start offset, used to calculate global position
+        /// Start offset, used to calculate current position inside shape.
         offset: Vec2,
     },
 }
@@ -46,9 +46,35 @@ impl CollisionShape {
             },
         }
     }
+    
+    /// Create [`CollisionShape::Aabb`]
+    pub fn new_aabb(offset: Vec2, size: Vec2) -> Self {
+        let half_size = Vec2 { x: size.x / 2f32, y: size.y / 2f32 };
+        Self::Aabb { shape: Aabb2d::new(offset, half_size), offset, size }
     }
 
-#[derive(Component)]
+    /// Create [`CollisionShape::Circle`]
+    pub fn new_circle(offset: Vec2, radius: f32) -> Self {
+        Self::Circle { shape: BoundingCircle::new(offset, radius), offset }
+    }
+
+    /// Returns current centered offset for the shape
+    pub fn current_offset(&self) -> Vec2 {
+        match self {
+            Self::Aabb { shape, .. } => {
+                Vec2::new(
+                    (shape.min.x + shape.max.x) / 2.,
+                    (shape.min.y + shape.max.y) / 2.,
+                )
+            },
+            Self::Circle { shape, .. } => {
+                shape.center
+            },
+        }
+    }
+}
+
+#[derive(Component, PartialEq, Debug)]
 #[require(Transform)]
 /// Component, handling multiple collision shapes for single entity
 pub struct Collider {
@@ -79,50 +105,80 @@ impl Collider {
     /// Returns true if any of self shapes intersect other's shapes, respecting groups.
     /// Wrapper around [intersects_unchecked](Self::intersects_unchecked)
     pub fn intersects(&self, other: &Collider) -> bool {
+        println!("groups: {}", self.check_mask & other.mask );
         if self.check_mask & other.mask == 0 {
             return false;
         }
         self.intersects_unchecked(other)
     }
 
-    /// Update shapes global position
+    /// Update shapes' current position
-    pub fn update_shapes_position(&mut self, global_position: &Vec2) {
+    pub fn update_shapes_position(&mut self, new_position: &Vec2) {
         for shape in self.shapes.iter_mut() {
             match shape {
                 CollisionShape::Aabb { shape, offset, size } => {
-                    shape.min.x = global_position.x + offset.x;
+                    shape.min.x = new_position.x + offset.x - size.x / 2.;
-                    shape.min.y = global_position.y + offset.y;
+                    shape.min.y = new_position.y + offset.y - size.y / 2.;
                     shape.max.x = shape.min.x + size.x;
                     shape.max.y = shape.min.y + size.y;
                 },
                 CollisionShape::Circle { shape, offset } => {
-                    shape.center.x = global_position.x + offset.x;
+                    shape.center.x = new_position.x + offset.x;
-                    shape.center.y = global_position.y + offset.y;
+                    shape.center.y = new_position.y + offset.y;
                 },
             }
         }
     }
 }
 
-#[derive(Component)]
+#[derive(Component, Debug)]
+/// Add this component on entities, which have their [`Transform`] updated.
+/// Used for [`update_collider_shapes`] system
 pub struct UpdateShapes;
 
-/// Update collider shapes to match new global transform
+/// Update collider shapes to match new [`Transform`]
 pub fn update_collider_shapes(
     mut commands: Commands,
-    colliders: Query<(&mut Collider, &GlobalTransform, Entity), With<UpdateShapes>>,
+    colliders: Query<(&mut Collider, &Transform, Entity), With<UpdateShapes>>,
 ) {
     for (mut collider, transform, entity) in colliders {
-        collider.update_shapes_position(&transform.translation().xy());
+        collider.update_shapes_position(&transform.translation.xy());
         commands.entity(entity).remove::<UpdateShapes>();
     }
 }
 
+#[derive(EntityEvent, Debug)]
+/// Emitted when colliders intersect in [`check_for_collisions`] system
+pub struct CollisionEvent {
+    /// Entity, whose [`Collider`] detected another [`Collider`]
+    pub entity: Entity,
+    /// Entity, whose [`Collider`] was detected as intersecting
+    pub detected: Entity,
+}
+
+/// Check each [`Collider`] for collisions with another colliders.
+/// Triggers [`CollisionEvent`] on collider intersection
+pub fn check_for_collisions(
+    mut commands: Commands,
+    colliders: Query<(&Collider, Entity)>,
+) {
+    let mut visited_colliders: Vec<&Collider> = Vec::new();
+    for (collider, entity) in colliders.iter() {
+        for (other_collider, other_entity) in colliders.iter().filter(|(c, _)| !visited_colliders.contains(c)) {
+            if collider.intersects(other_collider) {
+                commands.trigger(CollisionEvent { entity, detected: other_entity });
+            }
+        }
+        visited_colliders.push(collider);
+        println!("{visited_colliders:?}");
+    }
+}
+
 /// Plugin that adds collision systems
 pub struct CollisionPlugin;
 
 impl Plugin for CollisionPlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(Update, update_collider_shapes);
+        app.add_systems(PostUpdate, (update_collider_shapes, check_for_collisions).chain());
     }
 }

tests/collider_position.rs

@@ -0,0 +1,130 @@
+use bevy::prelude::*;
+use bevy_collision_plugin::{Collider, CollisionEvent, CollisionPlugin, CollisionShape, UpdateShapes};
+
+const CHECKED_GROUPS: usize = 1 >> 0 | 1 >> 1;
+
+#[derive(Component)]
+struct MovingCollider;
+
+fn moving_collider_bundle() -> impl Bundle {
+    (   
+        Collider {
+            shapes: vec![
+                CollisionShape::new_aabb(Vec2::new(0., 0.), Vec2::new(10., 10.)),
+                CollisionShape::new_circle(Vec2::new(0., 15.), 5.),
+            ],
+            mask: 0,
+            check_mask: CHECKED_GROUPS,
+        },
+        Transform::from_translation(Vec3::new(0., 0., 0.)),
+        MovingCollider,
+    )
+}
+
+fn zerogroup_collider_bundle() -> impl Bundle {
+    (
+        Collider {
+            shapes: vec![
+                CollisionShape::new_aabb(Vec2::new(0., 0.), Vec2::new(10., 10.)),
+            ],
+            mask: 1 >> 0,
+            check_mask: 0,
+        },
+        Transform::from_translation(Vec3::new(53., 5., 0.)),
+    )
+}
+
+fn firstgroup_collider_bundle() -> impl Bundle {
+    (
+        Collider {
+            shapes: vec![
+                CollisionShape::new_circle(Vec2::new(0., 0.), 5.),
+            ],
+            mask: 1 >> 1,
+            check_mask: 0,
+        },
+        Transform::from_translation(Vec3::new(53., 18., 0.)),
+    )
+}
+
+fn move_collider(
+    mut commands: Commands,
+    query: Query<(Entity, &mut Transform), With<MovingCollider>>,
+) {
+    for (entity, mut transform) in query {
+        transform.translation.x += 50.;
+        commands.entity(entity)
+            .insert(UpdateShapes);
+    }
+}
+
+fn setup(
+    mut commands: Commands,
+) {
+    commands.spawn(moving_collider_bundle());
+}
+
+fn configured_app() -> App {
+    let mut app = App::new();
+    
+    app.add_plugins(CollisionPlugin)
+        .add_systems(Startup, setup)
+        .add_systems(Update, move_collider);
+
+    app
+}
+
+#[test]
+fn collider_shapes_update_properly() {
+    let mut app = configured_app();
+
+    app.update();
+
+    let mut query = app.world_mut().query::<&Collider>();
+    for collider in query.iter(app.world()) {
+        let aabb_offset = collider.shapes[0].current_offset();
+        let circle_offset = collider.shapes[1].current_offset();
+
+        let expected_aabb = Vec2::new(50., 0.);
+        let expected_circle = Vec2::new(50., 15.);
+
+        assert_eq!(aabb_offset, expected_aabb);
+        assert_eq!(circle_offset, expected_circle);
+    }
+}
+
+#[derive(Resource)]
+struct CollisionList(Vec<Entity>);
+
+fn setup_others(
+    mut commands: Commands,
+) {
+    commands.spawn(zerogroup_collider_bundle());
+    commands.spawn(firstgroup_collider_bundle());
+}
+
+fn on_collision_event(
+    event: On<CollisionEvent>,
+    mut res: ResMut<CollisionList>,
+) {
+    if !res.0.contains(&event.detected) {
+        res.0.push(event.detected);
+    }
+}
+
+#[test]
+fn collider_detects_different_groups() {
+    let mut app = configured_app();
+
+    app.insert_resource(CollisionList(vec![]))
+        .add_systems(Startup, setup_others)
+        .add_observer(on_collision_event);
+
+    app.update();
+    
+    let collisions = app.world().get_resource::<CollisionList>().unwrap();
+    let got_collisions = collisions.0.len();
+    let expected = 2;
+
+    assert_eq!(got_collisions, expected);
+}