How to use the filament.init function in filament

* you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import * as Filament from "filament";
import * as glm from "gl-matrix";

Filament.init([], () => {
    window["vec3"] = glm.vec3;
    window["app"] = new App(document.getElementsByTagName('canvas')[0]);
});

class App {
    public readonly camera: Filament.Camera;
    private canvas: HTMLCanvasElement;
    private engine: Filament.Engine;
    private scene: Filament.Scene;
    private view: Filament.View;
    private swapChain: Filament.SwapChain;
    private renderer: Filament.Renderer;
    private bgcolor: number[];

    constructor(canvas) {
      this.canvas = canvas;