Description Retrieves ray data for the previous "Live" ray. Generally used after GetLastRay or GetLastFilteredRay. Note that when used after GetLastFilteredRay the same filter that was applied to getting the last ray will apply to all previous rays until reset by calling the (unfiltered) GetFirstRay or GetLastRay command.
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 success = GetPreviousRay( id, tr )
Parameters success (Boolean) Returns True is successful and False if a problem is encountered.
id As Long (or Huge_) Index into the ray buffer for the last ray that was retrieved prior to calling this function. After execution, this variable contains the index into the ray buffer for the most recently retrieved ray.
tr As T_RAY Structure to be loaded with ray data.
Example The example below shows the standard ray buffer reverse looping construction.
Dim success As Boolean Dim curRay As Long Dim tRay as T_RAY
success = GetLastRay( curRay, tRay ) While success 'Do something with tRay structure here... success = GetPreviousRay( curRay, tRay ) Wend
See Also
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