Struct Table

pub struct Table { /* private fields */ }

A column-oriented structure-of-arrays based storage for Components of entities in a World.

Conceptually, a Table can be thought of as an HashMap<ComponentId, Column>, where each Column is a type-erased Vec<T: Component>. Each row corresponds to a single entity (i.e. index 3 in Column A and index 3 in Column B point to different components on the same entity). Fetching components from a table involves fetching the associated column for a component type (via its ComponentId), then fetching the entity’s row within that column.

Implementations

impl Table

pub fn entities(&self) -> &[Entity]

Fetches a read-only slice of the entities stored within the Table.

pub fn get_column(&self, component_id: ComponentId) -> Option<&Column>

Fetches a read-only reference to the Column for a given Component within the table.

Returns None if the corresponding component does not belong to the table.

pub fn has_column(&self, component_id: ComponentId) -> bool

Checks if the table contains a Column for a given Component.

Returns true if the column is present, false otherwise.

pub fn entity_count(&self) -> usize

Gets the number of entities currently being stored in the table.

pub fn component_count(&self) -> usize

Gets the number of components being stored in the table.

pub fn entity_capacity(&self) -> usize

Gets the maximum number of entities the table can currently store without reallocating the underlying memory.

pub fn is_empty(&self) -> bool

Checks if the Table is empty or not.

Returns true if the table contains no entities, false otherwise.

pub fn iter(&self) -> impl Iterator<Item = &Column>

Iterates over the Columns of the Table.