XNA MathHelper.SmoothStep? How does it work?

Question

I have a car and when accelerating i want the speed to increse "slowly"..

After looking at a few sites i came to the conclusion that the SmoothStep method could be used to do that?

I pretty much know how to move textures and stuff, so an example where smoothstep is used to increase value in a float or something like that, would be extremely helpful!

Thanks in advance :)

I think it is sad there isnt examples for all the methods in the MSDN library.

Answer 1

From this documentation it looks like SmoothStep takes 3 arguments - the two values you want to move between and the amount between them which probably needs to be between 0 and 1.
So say you have a float f that increments linearly from 0 to the destination speed over a period of time. instead of using f directly as the speed, using SmoothStep would look like this:

float speed = MathHelper.SmoothStep(0, destSpeed, f/destSpeed);

It really is amazing how bad this documentation is.

Answer 2

Very useful site i found in the meantime. http://johnnygizmo.blogspot.com/2008/10/xna-series-basic-ai.html

And thanks a lot for the answers! :)

But then what is SmoothStep made to do? Where do i use it instead?