var textureLoader = new THREE.TextureLoader();

var mapLeft = textureLoader.load("img/rotate_left.png" );
var materialLeft = new THREE.SpriteMaterial( { map: mapLeft, color: 0xffffff, fog: true } );
var spriteLeft = new THREE.Sprite(materialLeft);
spriteLeft.name = 'rotate_left';

var intersect = app.raycaster.intersectObjects(app.scene.children);