serializeScene function

SceneDocument serializeScene(Node root, { FsceneComponentRegistry? registry, })

Serializes the live Node graph rooted at root into a new SceneDocument.

root is treated as the synthesized realization root (as returned by realizeScene): its handedness is read back into the stage, and its children become the document's root nodes. Nodes realized from a document keep their identity-tag ids, so a load/edit/save cycle is rename-proof and diff-friendly; untagged (hand-built) nodes mint fresh ids. Skins, the root's parsed animations, and lazy prefab placeholders serialize too; a loaded lazy subtree serializes as its placeholder (the streamed content belongs to the referenced prefab, not this document). Components are serialized through registry (the built-ins by default); a component no codec claims is skipped with a debug warning.

Implementation

SceneDocument serializeScene(Node root, {FsceneComponentRegistry? registry}) {
  final reg = registry ?? defaultComponentRegistry();
  final document = SceneDocument();
  document.stage.handedness = root.localTransform.determinant() < 0
      ? Handedness.right
      : Handedness.left;
  final context = SerializeContext(document);

  // First pass: assign every node its id, reusing realize-time identity tags
  // where present (skipping duplicates from app-side clones). Newly assigned
  // ids are tagged back onto the nodes so follow-up passes (`serializeViews`
  // referencing camera nodes) and future saves see stable ids.
  final ids = <Node, LocalId>{};
  final used = <LocalId>{};
  void assign(Node node) {
    final tagged = nodeFsceneId(node);
    final id = tagged != null && used.add(tagged) ? tagged : document.newId();
    ids[node] = id;
    if (id != tagged) {
      used.add(id);
      tagNodeId(node, id);
    }
    for (final child in node.children) {
      assign(child);
    }
  }

  for (final child in root.children) {
    assign(child);
  }

  for (final child in root.children) {
    final spec = _serializeNode(child, document, reg, context, ids);
    document.addNode(spec, root: true);
  }
  _serializeAnimations(root, document, ids);
  return document;
}