Function interpolatorStepped

Returns a function that interpolates from A to B. It steps through the interpolation with each call to the returned function. This means that the incrementAmount will hinge on the rate at which the function is called. Alternatively, consider https://api.ixfx.fun/_ixfx/modulation/interpolatorInterval/ which steps on the basis of clock time.

// Interpolate from 0..1 by 0.01
const v = interpolatorStepped(0.01, 100, 200);
v(); // Each call returns a value closer to target
// Eg: 100, 110, 120, 130 ...
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Under the hood, it calls interpolate with an amount that increases by incrementAmount each time.

When calling v() to step the interpolator, you can also pass in new B and A values. Note that the order is swapped: the B (target) is provided first, and then optionally A.

const v = interpolatorStepped(0.1, 100, 200); // Interpolate 100->200
v(300, 200); // Retarget to 200->300 and return result
v(150); // Retarget 200->150 and return result
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This allows you to maintain the current interpolation progress.