On 2012/06/30 09:47, sven falempin wrote: > Stuart, > > The flag is there to not change old behavior.
Since masking with all 0's is pointless, you can use that to identify the standard behaviour, checking against 0 is a fast way to determine if the mask should be applied at all (this means a mask of all 1's would have the same filtering effect as no mask, but would be slightly slower).
