cene();
            scenePromise.then(meshes => {
                scene.addMesh(meshes);
            });
            drawAll();
        }

        render();
        function getScene() {
            var url = 'gltf/city_model/scene.gltf';
            return gltf.Ajax.getJSON(url, {}).then((json) => {
                const loader = new gltf.GLTFLoader('gltf/city_model', json);
                return loader.load().then(gltfData => {
                    const gltfPack = reshader.GLTFHelper.exportGLTFPack(gltfD