A light source positioned directly above the scene, with color fading from the
sky color to the ground color.
This light cannot be used to cast shadows.
var light = new THREE.HemisphereLight( 0xffffbb, 0x080820, 1 );
scene.add( light );
[page:Integer skyColor] - (optional) hexadecimal color of the sky. Default is 0xffffff.
[page:Integer groundColor] - (optional) hexadecimal color of the ground. Default is 0xffffff.
[page:Float intensity] - (optional) numeric value of the light's strength/intensity. Default is 1.
Creates a new [name].
See the base [page:Light Light] class for common properties.
This is set to *undefined* in the constructor as hemisphere lights cannot cast shadows.
The light's sky color, as passed in the constructor. Default is a new [page:Color] set to white (0xffffff).
The light's ground color, as passed in the constructor. Default is a new [page:Color] set to white (0xffffff).
Used to check whether this or derived classes are hemisphere lights. Default is *true*.
You should not change this, as it used internally for optimisation.
This is set equal to [page:Object3D.DefaultUp] (0, 1, 0), so that the light shines from the top down.
Copies the value of [page:.color color], [page:.intensity intensity] and [page:.groundColor groundColor] from the [page:Light source] light into this one.
[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]