fix renderOrder ReflectorRTT

examples/js/objects/ReflectorRTT.js

@@ -4,6 +4,8 @@ THREE.ReflectorRTT = function ( geometry, options ) {
 
 	this.geometry.setDrawRange( 0, 0 ); // avoid rendering geometry
 
+	this.renderOrder = -Infinity; // render RTT first
+
 };
 
 THREE.ReflectorRTT.prototype = Object.create( THREE.Reflector.prototype );