def lerp(a, b, t):
 if (t < 0.0):
  return a
 if (t > 1.0):
  return b
 return (a + ((b - a) * t))

def lerp ( a , b , t ) : if ( t < 0.0 ) : return a if ( t > 1.0 ) : return b return ( a + ( ( b - a ) * t ) )
returns the linear interpolation between a and b at time t between 0 .