When using averaged noise with height > MAX_RES (i.e. 4096),
multiple threads would access the same prev_shift slot,
leading to races. Fix this by disabling slice threading
in such scenarios.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
"all" only exists to set options; it does not need the big arrays
contained in FilterParams.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
