Papervision3D: understanding Plane object – part 4

package {
	import flash.display.Sprite;
	import flash.events.Event;
	import org.papervision3d.cameras.Camera3D;
	import org.papervision3d.render.BasicRenderEngine;
	import org.papervision3d.scenes.Scene3D;
	import org.papervision3d.view.Viewport3D;
	import org.papervision3d.objects.primitives.Plane;
	import org.papervision3d.materials.ColorMaterial;
	import org.papervision3d.events.InteractiveScene3DEvent;
	public class papervision extends Sprite {
		public var viewport:Viewport3D=new Viewport3D(500,400,false,true);
		public var scene:Scene3D = new Scene3D();
		public var camera:Camera3D = new Camera3D();
		public var renderer:BasicRenderEngine = new BasicRenderEngine();
		public var back_material:ColorMaterial=new ColorMaterial(Math.random()*0xffffff);
		public var front_material:ColorMaterial=new ColorMaterial(Math.random()*0xffffff);
		public var front_plane:Plane=new Plane(front_material,200,300,4,5);
		public var back_plane:Plane=new Plane(back_material,200,300,4,5);
		public var rotation_speed=4;
		public function papervision() {
			addChild(viewport);
			camera.focus=100;
			camera.zoom=10;
			back_plane.rotationY=180;
			front_material.interactive=true;
			back_material.interactive=true;
			scene.addChild(front_plane);
			scene.addChild(back_plane);
			front_plane.name = "FRONT";
			back_plane.name = "BACK";
			back_plane.addEventListener(InteractiveScene3DEvent.OBJECT_PRESS,on_plane_clicked);
			front_plane.addEventListener(InteractiveScene3DEvent.OBJECT_PRESS,on_plane_clicked);
			addEventListener(Event.ENTER_FRAME, render);
		}
		public function render(e:Event) {
			front_plane.yaw(rotation_speed);
			back_plane.yaw(rotation_speed);
			renderer.renderScene(scene, camera, viewport);
		}
		public function on_plane_clicked(e:InteractiveScene3DEvent) {
			rotation_speed*=-1;
			switch (e.displayObject3D.name) {
				case "FRONT" :
					front_material.fillColor=Math.random()*0xffffff;
					break;
				case "BACK" :
					back_material.fillColor=Math.random()*0xffffff;
					break;
			}
		}
	}
}