nalLight.shadow.windowSize = 100;
		directionalLight.castShadow = true;
		scene.add(directionalLight);

		const camera = new t3d.Camera();
		camera.position.set(0, 80, 100);
		camera.lookAt(new t3d.Vector3(0, 0, 0), new t3d.Vector3(0, 1, 0));
		camera.setPerspective(45 / 180 * Math.PI, width / height, 1, 1000);
		scene.add(camera);

		// input

		const gui = new GUI();
		gui.add({ flatShading: true }, 'flatShading').onChange(value => {
			phong.shading = value ? t3d.SHADING_TYPE.FLAT_SHADING : t3d.SHADING_T