Description Retrieves the identifier of the oldest parent of a ray specified in the Ray Buffer. Depending on the number of rays traced, it may be necessary to dimension ray index and ray counter variables as data type Huge_ instead of Long. Please see Multi-threaded Raytracing for more information.
Syntax ancestor = GetRayOldestAncestor ( id )
Parameters ancestor (Long or Huge_) Identifier of the oldest ancestor of the ray specified by id.
id As Long (or Huge_) Identifier of the ray.
Remarks This function retrieves the identifier of the oldest ancestor of a ray specified in the Ray Buffer. If there is a problem, the function sets an error and returns -1.
If the ray has not split during a raytrace, then the ray is its own oldest ancestor. If the ray has an ancestry level of 1, then the ray's oldest ancestor is its parent. It the ray has an ancestry level of 2, then its oldest ancestor is its grandparent. Etc.
See Also Examples
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