Seriously guys, don't write: a = lerp(a, B, 1.0 - exp(-delta * RATE2)) Write: a = lerp(a, B, -expm1(-delta * RATE2)) This is precisely the situation whe

Seriously guys, don't write: a = lerp(a, B, 1.0 - exp(-delta * RATE2)) Write: a = lerp(a, B, -expm1(-delta * RATE2)) This is precisely the situation where you really want to use expm1: https://www.johndcook.com/blog/cpp_expm1/ https://www.johndcook.com/blog/cpp_expm1/ And (as pointed in the above) if you're worried about the slowness of it, just Taylor expand it to x+x²/2. Finally, unless division is too costly, do: a = lerp(a, B, -expm1(delta / -T)) Where T is the “time constant” (which you can intuitively express in time units, like seconds): https://en.wikipedia.org/wiki/Exponential_smoothing#Time_constant https://en.wikipedia.org/wiki/Exponential_smoothing#Time_con... It's not the half-life (sorry) but it's still a lot more intuitive as a parameter.