PointLight constructor
Implementation
PointLight(color, [double? intensity, double? distance, double? decay])
: super(color, intensity) {
// remove default 0 for js 0 is false but for dart 0 is not.
// PointLightShadow.updateMatrices far value
this.distance = distance;
this.decay = decay ?? 1; // for physically correct lights, should be 2.
shadow = PointLightShadow();
}