qreal value(qreal t)
{
qreal o = (_o < 0) ? 1.70158f : _o;
switch(_t) {
case In:
return easeInBack(t, o);
case Out:
return easeOutBack(t, o);
case InOut:
return easeInOutBack(t, o);
case OutIn:
return easeOutInBack(t, o);
default:
return t;
}
}
double valueForProgress ( double a_fProgress ) const
{
double fOvershoot = (m_fOvershoot < 0) ? 1.70158 : m_fOvershoot;
switch ( m_eType )
{
case In:
return easeInBack(a_fProgress, fOvershoot);
case Out:
return easeOutBack(a_fProgress, fOvershoot);
case InOut:
return easeInOutBack(a_fProgress, fOvershoot);
case OutIn:
return easeOutInBack(a_fProgress, fOvershoot);
default:
return a_fProgress;
}
}
static qreal easeInBack(qreal t)
{
const qreal s = 1.70158;
return easeInBack(t, s);
}
/**
* Easing equation function for a back (overshooting cubic easing: (s+1)*t^3 - s*t^2) easing out/in: deceleration until halfway, then acceleration.
*
* @param t Current time (in frames or seconds).
* @param s Overshoot ammount: higher s means greater overshoot (0 produces cubic easing with no overshoot, and the default value of 1.70158 produces an overshoot of 10 percent).
* @return The correct value.
*/
static qreal easeOutInBack(qreal t, qreal s)
{
if (t < 0.5) return easeOutBack (2*t, s)/2;
return easeInBack(2*t - 1, s)/2 + 0.5;
}
