A light source. This type describes an interface and is not intended to be instantiated directly. Together,
color and intensity produce a high-dynamic-range light color. intensity can also be used individually to dim or brighten the light without changing the hue.
成员(属性)
color : Color
The color of the light.
The intensity controls the strength of the light.
intensity has a minimum value of 0.0 and no maximum value.