Return a modifier indicating how the orientation of the child subcell
with the given traversal position [0..3] is related to the orientation
of the parent cell. The modifier should be XOR-ed with the parent
orientation to obtain the curve orientation in the child.
Return a modifier indicating how the orientation of the child subcell with the given traversal position [0..3] is related to the orientation of the parent cell. The modifier should be XOR-ed with the parent orientation to obtain the curve orientation in the child.
POS_TO_ORIENTATIONpos -> orientation_modifier