ReadonlyhitClosest: the ray hit; any: it is blocked.
ReadonlyinstanceClosest hits: the hit's instance and triangle (0 otherwise).
ReadonlyinstanceInstances entered (a merged mesh counts once).
ReadonlyinstancesInstances entered in which the walk accepted a hit (closest) or found the blocker (any).
ReadonlymeshInner nodes of mesh trees whose two child boxes were tested.
ReadonlystepsIterations of the walk's loop: one per node or leaf processed, both levels.
ReadonlytClosest: the hit's distance (negative on a miss). Any: 1 blocked, -1 clear.
ReadonlytopInner nodes of the top level whose two child boxes were tested.
ReadonlytriangleReadonlytriangle
One ray's counted walk (GpuRays.countWalk): its hit and the walk's work, from a
BvhWalkCountsrecord.