Interface TopLevelShape

Every leaf child slot, in record order.

Levels of nodes on the longest path (bounds the traversal stack).

nodeCount nodes in the tracer's layout. A leaf's index is a record index.

Parent of each node as a child slot (parent * 2 + side); see @pmndrs/bvh gpu-refit.ts.

The scene instance slot each record holds.

relativeSahCost of the tree as built: the baseline its quality is compared with.