OutLowerIndex is populated with the index of the last element in InArray with a Timestamp less than or equal to InTimestamp. On error, this is set to INDEX_NONE OutUpperIndex is populated with the index of the first element in InArray with a Timestamp greater than InTimestamp. On error, this is set to INDEX_NONE OutAlpha is a number between 0.f and 1.f which describes the blending between the lower and upper indices. 0.f refers OutLowerIndex and 1.f to OutUpperIndex.