/** Planar ring
 * @author: Phil Gage
 */
class Ring extends AbstractPlane {
    double innerRadius, outerRadius;

    Ring (Point point, Vector3 normal, double innerRadius,
         double outerRadius, Color color) {
        super(point,normal,color);
        this.innerRadius = innerRadius;
        this.outerRadius = outerRadius;
    }

    double intersect (Ray ray, Intersection intersection) {
        double t = super.intersect (ray,intersection);
        if (t > 0.0) {
            double dist = point.distance (intersection.point);
            if (dist >= innerRadius && dist <= outerRadius)
                return t;
        }
        return 0.0;
    }

    /** Return bounding box around this object, could improve */
    Extent getExtent () {
        return new Extent (
            new Point (point.x - outerRadius,
                       point.y - outerRadius,
                       point.z - outerRadius),
            new Point (point.x + outerRadius,
                       point.y + outerRadius,
                       point.z + outerRadius));
    }

}