gistfile1.txt

float linearTween(float t, float start, float end){
  return t * start + (1-t) * end;
}

float QuadraticEaseInOut(float t, float start, float end){
  float middle = (start + end) / 2;
  t = 2 * t;
  if (t <= 1)
    return linearTween(t*t, start, middle);
  t-= 1;
  return linearTween(t*t, middle, end);
}