An improved version of the math.smoothstep function which has zero 1st and 2nd order derivatives at t=0 and t=1.
See https://en.wikipedia.org/wiki/Smoothstep#Variations for more details.
The lower bound of the interpolation range.
The upper bound of the interpolation range.
The value to interpolate.
The smoothly interpolated value clamped between zero and one.
An improved version of the math.smoothstep function which has zero 1st and 2nd order derivatives at t=0 and t=1.
See https://en.wikipedia.org/wiki/Smoothstep#Variations for more details.