update method
Implementation
@override
void update(double dt) {
// https://easings.net/ja#easeOutElastic
var value = dt;
if (dt != 0 && dt != 1) {
var c4 = (2 * math.pi) / 3;
value = math.pow(2, -10 * dt) * math.sin((dt * 10 - 0.75) * c4) + 1;
}
innerAction.update(value);
}