Bounding volume hierarchy with bounding volumes in prior space corresponding to subset of transform sub-tree bounds

Abstract

Techniques are disclosed relating to ray tracing, e.g., in graphics processors. Ray tracing embodiments may utilize a bounding volume hierarchy (BVH) acceleration data structure (ADS) that includes a hierarchy of bounding volumes. A graphics processor may traverse the ADS, testing for intersections with bounding volumes, to determine which primitives to test for a given ray. Some nodes may be transform nodes (e.g., instance nodes) that correspond to a ray transform before further traversal. In disclosed embodiment, one or more levels below the transform node may be reverse transformed and included above the transform node. This may advantageously avoid a ray transform operation for rays that would not have hit in the first one or more levels of the transform sub-tree.