Tile3d

Mutated by external-tileset grafts on the fetch coroutine; read by the render thread.

Null when this tile is structural (no renderable payload). Cleared when the URI pointed at an external tileset.json and its root has been grafted into children.

Spec-defined geometric error in meters.

Original .json URI when children were grafted from an external tileset; null otherwise. Preserved so the sweep can restore the wrapper for re-fetch when the subtree is evicted.

When non-null, traversal materialises children via SubtreeReader.

Set by the traverser when finer descendants are also in selection (skip-LoD). Drives stencil masking in the draw path so fallback tiles fill only gaps.

Set by the traverser when the tile was accepted only as a shadow caster (outside the view frustum). The layer enqueues it occluder-only: cascade depth pass, no color pass.

Last frame this tile participated in traversal — read by the layer's cold-subtree sweep.

Bottom-up "children take over rendering" flag computed by the traverser.

Outermost-fallback subtree id (0 = no fallback ancestor → stencil bypassed; 1..255 = inside a fallback subtree). Non-fallback tiles write; fallback tiles draw where stencil != this id.

This tile's tile-to-world composed with all ancestors'.

Scratch sort key set by Traverser each frame for distance-first ordering. Direct primitive field — avoids the boxed HashMap<Tile3d, Double> lookup that showed up as Double.valueOf 271 samples on the main thread at globe scale.