Struct Selection 

pub struct Selection {
    pub entities: HashSet<Entity>,
    pub last_pick: Option<PickPoint>,
}

World-global selection state — current entity set plus last hit point.

Insert via World::insert_resource before any system that reads it. The TS helper emits both single-click and marquee events; both flow into apply_pick / apply_pick_rect.

Fields

entities: HashSet<Entity>

Currently selected entities.

last_pick: Option<PickPoint>

World-space point of the most recent successful click pick, if any.

Implementations

impl Selection

pub fn new() -> Self

pub fn apply_pick( &mut self, entity: Option<Entity>, point: Option<PickPoint>, modifiers: PickModifiers, )

Apply a single-click pick.

• No modifier: replace selection with entity (or clear if None).
• Shift: toggle (add if absent, remove if present). Clicks on empty space are no-ops to avoid accidental clears mid-shift.
• Ctrl: subtract. Clicks on empty space are no-ops.
• Other modifier combinations: same as no-modifier on a hit; no-op on a miss.

last_pick is updated whenever point is provided, regardless of modifier — game code may want the cursor position even on a clear.

pub fn apply_pick_rect<I>(&mut self, entities: I, modifiers: PickModifiers)

where I: IntoIterator<Item = Entity>,

Apply a marquee pick.

• No modifier: replace selection with entities.
• Shift only: add entities to selection.
• Ctrl only: remove entities from selection.
• Alt only: keep only entities present in both the current selection and entities (set intersection).
• Other modifier combinations (Shift+Ctrl, Shift+Alt, Meta, …): same as no-modifier (replace).

Dispatch is on the full modifier bitmask — mirroring apply_pick — so that a multi-modifier marquee (e.g. a user holding Shift+Ctrl during a drag) falls through to the documented replace branch instead of being absorbed by the first matching single-modifier rule.

pub fn contains(&self, entity: Entity) -> bool

Whether entity is currently selected.

pub fn len(&self) -> usize

Number of selected entities.

pub fn is_empty(&self) -> bool

Whether the selection is empty.

Trait Implementations

impl Debug for Selection

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Selection

fn default() -> Self

Returns the “default value” for a type.