A class for generating a two-dimensional ring geometry.
var geometry = new THREE.RingGeometry( 1, 5, 32 );
		var material = new THREE.MeshBasicMaterial( { color: 0xffff00, side: THREE.DoubleSide } );
		var mesh = new THREE.Mesh( geometry, material );
		scene.add( mesh );
		
		
		innerRadius — Default is 0.5. 
		outerRadius — Default is 1. 
		thetaSegments — Number of segments.  A higher number means the ring will be more round.  Minimum is 3.  Default is 8. 
		phiSegments — Minimum is 1.  Default is 8.
		thetaStart — Starting angle. Default is 0. 
		thetaLength — Central angle.  Default is Math.PI * 2.
		
See the base [page:Geometry] class for common properties.
An object with a property for each of the constructor parameters. Any modification after instantiation does not change the geometry.
See the base [page:Geometry] class for common methods.
[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]