createApp() {
    this.resetSize();
    const width = this.getConf('width');
    const height = this.getConf('height');
    const transparent = this.getConf('transparent');
    const render = this.getConf('render');
    const clarity = this.getConf('clarity');
    const antialias = this.getConf('antialias');
    const useGL = render !== 'canvas';
    const key = `${this.type}_${render}`;
    settings.PRECISION_FRAGMENT = `${clarity}p`;

    const appOptions = {
      useGL,
      antialias,
    };
    // If set to transparent, override the default background color configuration
    if (transparent) {
      appOptions.transparent = true;
    } else {
      appOptions.backgroundColor = 0x000000;
    }

    const app = Pool.get(
      key,
      () =>
        new Application(width, height, appOptions),
    );
    app.renderer.resize(width, height);
    this.display = app.stage;
    this.app = app;
  }
Create webgl scene display object
@private