Struct Stage 

pub struct Stage {
    nodes: SlotMap<NodeId, Node>,
    root: NodeId,
}

Scene graph root.

Owns all nodes via a SlotMap keyed by NodeId. The tree is rooted at a Container returned by Stage::root. Child relationships are tracked inside each Container.

Fields

nodes: SlotMap<NodeId, Node>

root: NodeId

Implementations

impl Stage

pub fn new() -> Self

Construct a new stage with an empty root container.

pub fn root(&self) -> NodeId

The root node ID. Always a Container.

pub fn len(&self) -> usize

Total node count across the whole graph (including the root).

pub fn is_empty(&self) -> bool

true iff only the root exists.

pub fn get(&self, id: NodeId) -> Option<&Node>

Borrow a node by ID.

pub fn get_mut(&mut self, id: NodeId) -> Option<&mut Node>

Mutably borrow a node by ID.

pub fn add_child( &mut self, parent: NodeId, child: impl Into<Node>, ) -> Option<NodeId>

Insert child as a child of parent. Returns the new node ID.

child’s parent field is set; parent’s children list is appended.

Returns None if parent doesn’t exist.

pub fn detach(&mut self, child: NodeId) -> bool

Detach child from its parent without destroying it.

After this call the child is an orphan still reachable via Stage::get but no longer in any container’s children list. Returns true if the child was attached.

pub fn destroy(&mut self, id: NodeId) -> bool

Destroy a node and (recursively) all its descendants. Detaches from parent first.

Returns true if the node existed.

pub fn traverse_pre_order( &self, start: NodeId, visit: impl FnMut(NodeId, &Node), )

Pre-order traversal from a starting node. Visits the start first, then each child’s subtree in insertion order.

fn collect_descendants(&self, id: NodeId) -> Vec<NodeId>

Trait Implementations

impl Default for Stage

fn default() -> Self

Returns the “default value” for a type.