鼠标控制
			controls = new THREE.TrackballControls(camera, renderer.domElement);
			controls.rotateSpeed = 0.5;
			controls.minDistance = 500;
			controls.maxDistance = 6000;
			controls.addEventListener('change', render);

			// 自动更换
			var ini = 0;
			setInterval(function () {
				ini = ini >= 3 ? 0 : ini;
				++ini;
				switch (ini) {
					case 1:
						transform(targets.sphere, 1000);
						break;
					case 2:
						transform(targets.helix, 1000);
						break;
					case 3:
						transform(ta