Add `Blocks.position` function

src/block.rs

@@ -8,6 +8,7 @@ pub struct Block;
 pub struct Blocks<'w, 's> {
     commands: Commands<'w, 's>,
     block_resources: Res<'w, BlockResources>,
+    blocks: Query<'w, 's, &'static Transform, With<Block>>,
 }
 
 impl Blocks<'_, '_> {
@@ -19,6 +20,13 @@ impl Blocks<'_, '_> {
             Transform::from_translation(pos.as_vec3() + Vec3::ONE / 2.),
         ));
     }
+
+    /// Gets the position of a block entity, or `None`
+    /// if the given entity is not alive or not a block.
+    pub fn position(&self, entity: Entity) -> Option<IVec3> {
+        let transform = self.blocks.get(entity).ok();
+        transform.map(|t| t.translation.floor().as_ivec3())
+    }
 }
 
 #[derive(Resource)]

src/placement.rs

@@ -10,7 +10,6 @@ pub fn place_break_blocks(
     mouse_button_input: Res<ButtonInput<MouseButton>>,
     window: Single<(&Window, &CursorOptions)>,
     camera: Single<(&GlobalTransform, &Camera)>,
-    block_lookup: Query<&Transform, With<Block>>,
 ) {
     let (window, cursor) = window.into_inner();
     let (cam_transform, camera) = camera.into_inner();
@@ -27,7 +26,7 @@ pub fn place_break_blocks(
     let Some((block, hit)) = ray_cast.cast_ray(ray, settings).first() else {
         return; // ray didn't hit anything
     };
-    let Ok(block_transform) = block_lookup.get(*block) else {
+    let Some(block_pos) = blocks.position(*block) else {
         return; // entity hit is not a block
     };
 
@@ -36,9 +35,10 @@ pub fn place_break_blocks(
         commands.entity(*block).despawn();
     } else if mouse_button_input.just_pressed(MouseButton::Right) {
         // Create a new block next to the one that was just clicked.
-        let pos = block_transform.translation.floor().as_ivec3();
+
         // FIXME: This only works for axis-aligned normals.
         let offset = hit.normal.normalize().round().as_ivec3();
-        blocks.spawn(pos + offset);
+
+        blocks.spawn(block_pos + offset);
     }
 }