The refit's stats with diagnostics: true (see gpu-refit.ts).
GPU bytes of this refit's own buffers (the tree belongs to the caller, a shared box buffer to its pool).
Records the triangle step and the refit into pass. The vertices must be written by an earlier command.
StaticisThe tree moved to another place in the target's node buffer (a scene
that compacted its nodes, SceneTrees.trim): its root is now at
nodeWordOffset, as setTree's placement names it. The shape,
the triangles' place and the stats stay.
Stats readback (diagnostics only), as for the top-level refit: poll at a frame's start, copy after the submit's encode.
Compiles the kernels, or waits for the shared ones.
Takes the tree's shape from a CPU copy of its layout, and where the mesh sits in the GPU buffers (in words; 0 for a tree in its own buffers).
Refits one mesh's tree from moved vertices, every frame if need be. Needs
subgroups(for the refit).