function SpotLight(name, position, direction, angle, exponent, scene) {
            var _this = _super.call(this, name, scene) || this;
            _this.position = position;
            _this.direction = direction;
            _this.angle = angle;
            _this.exponent = exponent;
            return _this;
        }
Creates a SpotLight object in the scene with the passed parameters :
- `position` (Vector3) is the initial SpotLight position,
- `direction` (Vector3) is the initial SpotLight direction,
- `angle` (float, in radians) is the spot light cone angle,
- `exponent` (float) is the light decay speed with the distance from the emission spot.
A spot light is a simply light oriented cone.
It can cast shadows.
Documentation : http://doc.babylonjs.com/tutorials/lights