In order to make Square and Digital have the same period as Zigzag and Sawtooth in SM5, the period had to be changed. This means that syncing these modifiers using the same period precentage in SM5 is easy to do.
However, this also means that some math needs to be done when porting files that use Square & Digital to/from nITG.
Since the x position mods and z position mods used two different periods, two sets of equations are needed.
Note that -80% period would be input as -0.8. Getting 1.95 as a result is equivalent to 195%. ARROW_SIZE is usually 64, so use that in calculations. These equations also apply to the tangent version of Digital.
From nITG to SM5
Square & Digital: PeriodSM5 = ( PI * ( 60 + ( 60 * PeriodnITG ) ) - ARROW_SIZE ) / ARROW_SIZE
SquareZ & DigitalZ: PeriodSM5 = PI * ( 1 + PeriodnITG ) - 1
From SM5 to nITG
Square & Digital: PeriodnITG = ( ( ARROW_SIZE + ( ARROW_SIZE * PeriodSM5 ) ) / ( 60 * PI ) ) - 1
SquareZ & DigitalZ: PeriodnITG = ( ( 1 + PeriodSM5 ) / PI ) - 1