Question

I have a floating point value X which is animated. When in rest it’s at zero, but at times an outside source may change it to somewhere between -1 and 1.

If that happens I want it to go smoothly back to 0. I currently do something like

addToXspeed(-x * FACTOR);

// below is out of my control
function addToXspeed(bla) {
 xspeed += bla;
 x += xspeed;
}

every step in the animation, but that only causes X to oscillate. I want it to rest on 0 however.

(I’ve explained the problem in abstracts. The specific thing I’m trying to do is make a jumping game character balance himself upright in the air by applying rotational force)

Answer 1

Writing the question oftens results in realising the answer.

targetxspeed = -x * FACTOR;
addToXspeed(targetxspeed - xspeed);

// below is out of my control
function addToXspeed(bla) {
 xspeed += bla;
 x += xspeed;
}

So simple too