feat: add more world utilities (#465)

Closes #288

## Changes

- Add resources `MouseScreenPosition` and `MouseWorldPosition` which
both contain an `Option<Vec2>`
- Add utility methods `World::{get_,}entity_components` to query for the
components of an entity
- Clean up noisy data in `Entities` and `QueryItem` tests

framework_crates/bones_bevy_renderer/src/input.rs

@@ -1,9 +1,13 @@
 use super::*;
-use bevy::input::{
-    gamepad::GamepadEvent,
-    keyboard::KeyboardInput,
-    mouse::{MouseButtonInput, MouseMotion, MouseWheel},
+use bevy::{
+    input::{
+        gamepad::GamepadEvent,
+        keyboard::KeyboardInput,
+        mouse::{MouseButtonInput, MouseMotion, MouseWheel},
+    },
+    window::PrimaryWindow,
 };
+use bones::{MouseScreenPosition, MouseWorldPosition};
 
 pub fn insert_bones_input(
     In((mouse_inputs, keyboard_inputs, gamepad_inputs)): In<(
@@ -94,3 +98,32 @@ pub fn get_bones_input(
         },
     )
 }
+
+pub fn insert_mouse_position(
+    In((screen_pos, world_pos)): In<(Option<Vec2>, Option<Vec2>)>,
+    mut game: ResMut<BonesGame>,
+) {
+    game.insert_shared_resource(MouseScreenPosition(screen_pos));
+    game.insert_shared_resource(MouseWorldPosition(world_pos));
+}
+
+// Source: https://bevy-cheatbook.github.io/cookbook/cursor2world.html
+pub fn get_mouse_position(
+    mut q_primary_windows: Query<&Window, With<PrimaryWindow>>,
+    q_camera: Query<(&Camera, &GlobalTransform)>,
+) -> (Option<Vec2>, Option<Vec2>) {
+    match q_primary_windows
+        .get_single_mut()
+        .ok()
+        .and_then(Window::cursor_position)
+    {
+        None => (None, None),
+        screen_pos @ Some(sp) => match q_camera.get_single() {
+            Err(_) => (screen_pos, None),
+            Ok((camera, camera_transform)) => {
+                let world_pos = camera.viewport_to_world_2d(camera_transform, sp);
+                (screen_pos, world_pos)
+            }
+        },
+    }
+}

framework_crates/bones_bevy_renderer/src/lib.rs

@@ -224,6 +224,9 @@ impl BonesBevyRenderer {
             (
                 setup_egui,
                 get_bones_input.pipe(insert_bones_input).after(InputSystem),
+                get_mouse_position
+                    .pipe(insert_mouse_position)
+                    .after(InputSystem),
                 egui_input_hook,
             )
                 .chain()

framework_crates/bones_ecs/src/bitset.rs

@@ -59,6 +59,12 @@ impl BitSetVec {
     pub fn contains(&self, entity: Entity) -> bool {
         self.bit_test(entity.index() as usize)
     }
+
+    /// Set an entity on the the bitset.
+    #[inline]
+    pub fn set(&mut self, entity: Entity) {
+        self.bit_set(entity.index() as usize);
+    }
 }
 
 /// Creates a bitset big enough to contain the index of each entity.

framework_crates/bones_ecs/src/entities.rs

@@ -767,11 +767,11 @@ mod tests {
 
     #[derive(Debug, Clone, PartialEq, Eq, HasSchema, Default)]
     #[repr(C)]
-    struct A(String);
+    struct A(u32);
 
     #[derive(Debug, Clone, PartialEq, Eq, HasSchema, Default)]
     #[repr(C)]
-    struct B(String);
+    struct B(u32);
 
     #[test]
     fn query_item__get_single_with_one_required() {
@@ -794,7 +794,7 @@ mod tests {
             let mut comp = state.borrow_mut();
 
             let e = entities.create();
-            let a = A("e".to_string());
+            let a = A(1);
             comp.insert(e, a.clone());
 
             let query = ∁
@@ -812,10 +812,10 @@ mod tests {
             let mut comp = state.borrow_mut();
 
             let e1 = entities.create();
-            comp.insert(e1, A("e1".to_string()));
+            comp.insert(e1, A(1));
 
             let e2 = entities.create();
-            comp.insert(e2, A("e2".to_string()));
+            comp.insert(e2, A(2));
 
             let query = ∁
             let mut bitset = entities.bitset().clone();
@@ -848,8 +848,8 @@ mod tests {
 
         {
             let e = entities.create();
-            let a = A("e".to_string());
-            let b = B("e".to_string());
+            let a = A(1);
+            let b = B(1);
             state_a.borrow_mut().insert(e, a.clone());
             state_b.borrow_mut().insert(e, b.clone());
 
@@ -866,12 +866,12 @@ mod tests {
 
         {
             let e1 = entities.create();
-            state_a.borrow_mut().insert(e1, A("e1".to_string()));
-            state_b.borrow_mut().insert(e1, B("e1".to_string()));
+            state_a.borrow_mut().insert(e1, A(1));
+            state_b.borrow_mut().insert(e1, B(1));
 
             let e2 = entities.create();
-            state_a.borrow_mut().insert(e2, A("e2".to_string()));
-            state_b.borrow_mut().insert(e2, B("e2".to_string()));
+            state_a.borrow_mut().insert(e2, A(2));
+            state_b.borrow_mut().insert(e2, B(2));
 
             let query = (&state_a.borrow(), &state_b.borrow());
             let mut bitset = entities.bitset().clone();
@@ -892,7 +892,7 @@ mod tests {
         let state = AtomicCell::new(ComponentStore::<A>::default());
 
         let e = entities.create();
-        state.borrow_mut().insert(e, A("unexpected".to_string()));
+        state.borrow_mut().insert(e, A(u32::MAX));
 
         let query = &state.borrow();
         let bitset = Rc::new({
@@ -1033,7 +1033,7 @@ mod tests {
         let mut entities = Entities::default();
         (0..3).map(|_| entities.create()).count();
         let e = entities.create();
-        let a = A("a".to_string());
+        let a = A(4);
 
         let state = AtomicCell::new(ComponentStore::<A>::default());
         state.borrow_mut().insert(e, a.clone());
@@ -1064,7 +1064,7 @@ mod tests {
 
         for i in 0..3 {
             let e = entities.create();
-            let a = A(i.to_string());
+            let a = A(i);
             state.borrow_mut().insert(e, a.clone());
         }
 
@@ -1086,14 +1086,14 @@ mod tests {
         let _e1 = entities.create();
 
         let e2 = entities.create();
-        state_a.borrow_mut().insert(e2, A("a2".to_string()));
+        state_a.borrow_mut().insert(e2, A(2));
 
         let e3 = entities.create();
-        state_b.borrow_mut().insert(e3, B("b3".to_string()));
+        state_b.borrow_mut().insert(e3, B(3));
 
         let e4 = entities.create();
-        let a4 = A("a4".to_string());
-        let b4 = B("b4".to_string());
+        let a4 = A(4);
+        let b4 = B(4);
         state_a.borrow_mut().insert(e4, a4.clone());
         state_b.borrow_mut().insert(e4, b4.clone());
 
@@ -1127,7 +1127,7 @@ mod tests {
 
         {
             let e = entities.create();
-            let mut a = A("a".to_string());
+            let mut a = A(1);
             state.borrow_mut().insert(e, a.clone());
 
             let mut comp = state.borrow_mut();
@@ -1154,7 +1154,7 @@ mod tests {
 
         {
             let e = entities.create();
-            let a = A("a".to_string());
+            let a = A(1);
             state_a.borrow_mut().insert(e, a.clone());
 
             let comp_a = state_a.borrow();
@@ -1175,8 +1175,8 @@ mod tests {
 
         {
             let e = entities.create();
-            let a = A("a".to_string());
-            let mut b = B("b".to_string());
+            let a = A(1);
+            let mut b = B(1);
             state_a.borrow_mut().insert(e, a.clone());
             state_b.borrow_mut().insert(e, b.clone());
 

framework_crates/bones_ecs/src/world.rs

@@ -64,7 +64,7 @@ impl World {
     /// This will remove the component storage for all killed entities, and allow their slots to be
     /// re-used for any new entities.
     pub fn maintain(&self) {
-        let mut entities = self.resources.get_mut::<Entities>().unwrap();
+        let mut entities = self.resource_mut::<Entities>();
         for components in self.components.components.read_only_view().values() {
             let mut components = components.borrow_mut();
             let killed = entities.killed();
@@ -93,6 +93,42 @@ impl World {
         s.run(self, input)
     }
 
+    /// Get an entity's components.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the entity does not have the required components from the query.
+    pub fn entity_components<Q: QueryItem>(
+        &self,
+        entity: Entity,
+        query: Q,
+    ) -> <Q::Iter as Iterator>::Item {
+        self.get_entity_components(entity, query).unwrap()
+    }
+
+    /// Get an entity's components.
+    pub fn get_entity_components<Q: QueryItem>(
+        &self,
+        entity: Entity,
+        query: Q,
+    ) -> Option<<Q::Iter as Iterator>::Item> {
+        let mut bitset = BitSetVec::default();
+        if self.resource::<Entities>().bitset().contains(entity) {
+            bitset.set(entity);
+        }
+        query.apply_bitset(&mut bitset);
+        match query.get_single_with_bitset(bitset.into()) {
+            Ok(components) => Some(components),
+            Err(QuerySingleError::NoEntities) => None,
+            Err(QuerySingleError::MultipleEntities) => {
+                panic!(
+                    "Query returned a MultipleEntities error for a bitset that \
+                    contains at most one enabled bit"
+                )
+            }
+        }
+    }
+
     /// Initialize a resource of type `T` by inserting it's default value.
     pub fn init_resource<R: HasSchema + FromWorld>(&mut self) -> RefMut<R> {
         if unlikely(!self.resources.contains::<R>()) {
@@ -115,7 +151,7 @@ impl World {
         match self.resources.get::<T>() {
             Some(r) => r,
             None => panic!(
-                "Requested resource {} does not exist in the `World`.
+                "Requested resource {} does not exist in the `World`. \
                 Did you forget to add it using `world.insert_resource` / `world.init_resource`?",
                 std::any::type_name::<T>()
             ),
@@ -130,7 +166,7 @@ impl World {
         match self.resources.get_mut::<T>() {
             Some(r) => r,
             None => panic!(
-                "Requested resource {} does not exist in the `World`.
+                "Requested resource {} does not exist in the `World`. \
                 Did you forget to add it using `world.insert_resource` / `world.init_resource`?",
                 std::any::type_name::<T>()
             ),
@@ -201,6 +237,10 @@ mod tests {
 
     use super::FromWorld;
 
+    #[derive(Clone, Copy, HasSchema, Debug, Eq, PartialEq, Default)]
+    #[repr(C)]
+    struct C(u32);
+
     #[derive(Clone, HasSchema, Debug, Eq, PartialEq, Default)]
     #[repr(C)]
     struct Pos(i32, i32);
@@ -323,10 +363,28 @@ mod tests {
 
     #[test]
     fn world_is_send() {
+        fn send<T: Send>(_: T) {}
         send(World::new())
     }
 
-    fn send<T: Send>(_: T) {}
+    #[test]
+    fn get_entity_components() {
+        let w = World::default();
+
+        let (e1, e2) = {
+            let mut entities = w.resource_mut::<Entities>();
+            (entities.create(), entities.create())
+        };
+
+        let state = w.components.get::<C>();
+        let mut comp = state.borrow_mut();
+
+        let c2 = C(2);
+        comp.insert(e2, c2);
+
+        assert_eq!(w.get_entity_components(e1, &comp), None);
+        assert_eq!(w.get_entity_components(e2, &comp), Some(&c2));
+    }
 
     // ============
     //  From World

framework_crates/bones_framework/src/input/mouse.rs

@@ -55,3 +55,15 @@ pub enum MouseButton {
     /// Another mouse button with the associated number.
     Other(u16),
 }
+
+/// The position of the mouse in screen-space.
+///
+/// `None` if there is no cursor within the window.
+#[derive(HasSchema, Clone, Copy, Debug, Default, PartialEq)]
+pub struct MouseScreenPosition(pub Option<Vec2>);
+
+/// The position of the mouse in world-space.
+///
+/// `None` if there is no cursor within the window.
+#[derive(HasSchema, Clone, Copy, Debug, Default, PartialEq)]
+pub struct MouseWorldPosition(pub Option<Vec2>);