AE 回弹脚本

freq = 3;
decay = 5;
n = 0;
if (numKeys > 0){
 n = nearestKey(time).index;
 if (key(n).time > time) n--;
}
if (n > 0){
 t = time - key(n).time;
 amp = velocityAtTime(key(n).time - .001);
 w = freq*Math.PI*2;
 value + amp*(Math.sin(t*w)/Math.exp(decay*t)/w);
}else
 value