keep camera looking at a mesh, for threejs_playGnd

lookAt.js

       				
       				/* ------------------- INSTRUCTIONS -----

				to keep your camera focused on a mesh
				when the camera is moving and/or when 
				the mesh is moving, add the code below
				to your draw() function

				-------------------------------------- */

				camera.lookAt(mesh.position);
				
				/* --------------------------------------
				to see this in action add motion to your
				object, add the code below to your draw()
				-------------------------------------- */
				
				mesh.position.y = Math.sin( Date.now() * 0.002 ) * 450;
				
				/* --------------------------------------
				to get a sense of the space you can add a
				slightly tilted plane in your setup() 
				-------------------------------------- */
				
				wgeometry = new THREE.PlaneGeometry( 1000, 1000, 100, 100 );
				wmaterial = new THREE.MeshBasicMaterial( { color: 0x000000, wireframe: true, wireframeLinewidth: 1 } );
				wireplane = new THREE.Mesh( wgeometry, wmaterial );
				wireplane.rotation.x = - Math.PI / 3;
				scene.add( wireplane );