text: // loader_gltf.js
  
  var viewer = two.ui.scene_viewer(panel);
  two.ui.orbit_controls(viewer);
  
  var camera = viewer.camera;
  var scene = viewer.scene;
  
  if(init) {
      this.importerGltf = new two.ImporterGltf(app.gfx);
  
      camera.fov = 45.0; camera.near = 0.25; camera.far = 20.0;
      camera.eye = new two.vec3(-1.8, 0.9, 2.7);
      camera.target = new two.vec3(0.0, -0.2, -0.2);
  
      viewer.viewport.to_gamma = true;
      
      var texture = app.gfx.textures.file('cube/bridge.jpg.cube');
      
      var env = scene.env;
      env.radiance.texture = texture;
      env.background.texture = texture;
      env.background.mode = two.BackgroundMode.Panorama;
  
      var three = app.gfx.programs.fetch('pbr/three');
  
      var model = app.gfx.models.file('DamagedHelmet'); // .gltf');
      var mesh = model.get_mesh(0);
      mesh.material.program = three;
      mesh.material.pbr.albedo.texture.reload(app.gfx, true);
      
      var n = scene.nodes().add(new two.Node3());
      var i = scene.items().add(new two.Item(n, model));
  }
  