Re: [Algorithms] Formula for Damping f times

[Robin G. <rob...@gm...>]

exp() is one of the simplest and most direct math function to
implement. It should be approximately the cost of, say, five or
sequential six multiply-adds (and that includes range reduction and
reconstruction). Do not fear exp().

pow(), however, is a different story.

- Robin Green.


On Fri, Jun 5, 2009 at 8:06 AM, Jeff Russell<je...@8m...> wrote:
> x *= e ^ k * dt  (where k < 0)  is my good old standby. Works well with
> variable time steps. The call to exp() can be expensive, but if you have a
> lot of things decaying at the same rate you can compute exp( k * dt ) once
> for the frame and keep reusing it.
> cheers,
> jeff