gpvillamil

I need to variably increment and decrement a value, and have it return to the minimum value when a threshold is exceeded, and similarly, have it return to the MAXIMUM value when the mininum is exceeded.

So say my range is 1 to 16, and the current value is 16, if I increment then it should become 1. Conversely, if the value is 1 and I DECREMENT, then the value should go to 16.

The modulo operator (% ) seems to work for the incrementing case, but not for the decrementing case. Is there a good way to do this?

rollover-when-incrementing-and-decrementing-a-value

the modulo would work for decrementing too - but it does not work for negative numbers.

expr ((($i1%$i2)+($i2)*(($i1%$i2)==0))*($i1>=0))+(((($i1%$i2)+$i2)+(-$i2)*((($i1%$i2)+$i2)==0))*($i1

if it is sure that you are using numbers only within a smaller/limited range then

(Necroing thread as I found a good solution)

I love these zombie threads! I see your maths+mod and raise you an [expr] to get it in one go!

That definitely is more elegant than that monster expr above. I do a ton of research on the forum so might as well leave 'breadcrumbs' for the next guy!

*cough* That's not something I thought I'd ever see written on the Max forum!

Luke's formula can be made a bit more compact for ints:

A similar technique would work for floats if the expr object supported fmod(). On Max5 fmod isn't supported, but perhaps in Max6 (not installed on this machine, so I can't check).

The C-programmer in me is delighted by abusing the Boolean comparison as an implicit typecast to int (either 0 or 1). The nicely brought up, well-behaved PASCAL programmer in me is appalled by it. If you find multiplication with a comparison expression a little weird, it's easy enough to whip up a little abstraction that does the same thing. Something like the following:

to my excuse, mine allows offsets, i.e. a center another than 0

rollover when incrementing and decrementing a value