The color of the gradient at "middle" position in the sky as defined by gradientMidpoint. Only when type is GRADIENT.
The value between 0 and 1 that places the middle color of the gradient between respectively the bottom and top of the sky. Only when when type is GRADIENT.
The color of the gradient at the highest point in the sky (i.e the zenith). Only when type is GRADIENT.
The color of the gradient at the lowest point in the sky (typically below ground, under your feet). Only when type is GRADIENT.