A UGen that constrains a signal to a given range, by "folding" values outside the range. This is similar to the fold2 binary operator but permits both a lower range value lo and an upper range value hi .

Folding can be understood as "reflecting" around the boundaries. For example, if the upper margin is 3, then if an input value exceeds 3, the excess is negatively reflected; 3.1 becomes 2.9, 3.2 becomes 2.8, etc. until the lower margin is reached again where another reflection occurs. Likewise, if the lower margin is 1, then if an input value falls below 1, the undershoot is reflected; 0.9 becomes 1.1, 0.8 becomes 1.2, etc. until the upper margin is reached again where another reflection occurs.

Examples

// fold sawtooth wave to modulate timbre
play {
  val hi = SinOsc.ar(0.1).linExp(-1, 1, 0.01, 1.0)
  Fold.ar(Saw.ar(300), 0, hi) * 0.2 / hi
}