var Globe = function (radius, segments) {

  THREE.Object3D.call(this);

  this.name = "Globe";

  var that = this;

  // instantiate a loader
  var loader = new THREE.TextureLoader();

  // earth textures
  var textures = {
    'map': {
      url: 'relief.jpg',
      val: undefined
    },
    'bumpMap': {
      url: 'elev_bump_4k.jpg',
      val: undefined
    },
    'specularMap': {
      url: 'wateretopo.png',
      val: undefined
    }
  };

  var texturePromises = [], path = './';

  for (var key in textures) {
    texturePromises.push(new Promise((resolve, reject) => {
      var entry = textures[key]
      var url = path + entry.url
      loader.load(url,
        texture => {
          entry.val = texture;
          if (entry.val instanceof THREE.Texture) resolve(entry);
        },
        xhr => {
          console.log(url + ' ' + (xhr.loaded / xhr.total * 100) +
            '% loaded');
        },
        xhr => {
          reject(new Error(xhr +
            'An error occurred loading while loading: ' +
            entry.url));
        }
      );
    }));
  }

  // load the geometry and the textures
  Promise.all(texturePromises).then(loadedTextures => {
    var geometry = new THREE.SphereGeometry(radius, segments, segments);
    var material = new THREE.MeshPhongMaterial({
      map: textures.map.val,
      bumpMap: textures.bumpMap.val,
      bumpScale: 0.005,
      specularMap: textures.specularMap.val,
      specular: new THREE.Color('grey')
    });

    var earth = that.earth = new THREE.Mesh(geometry, material);
    that.add(earth);
  });

  // clouds
  loader.load('n_amer_clouds.png', map => {
    var geometry = new THREE.SphereGeometry(radius + .05, segments, segments);
    var material = new THREE.MeshPhongMaterial({
      map: map,
      transparent: true
    });

    var clouds = that.clouds = new THREE.Mesh(geometry, material);
    that.add(clouds);
  });
}

Globe.prototype = Object.create(THREE.Object3D.prototype);
Globe.prototype.constructor = Globe;