planets.js Example File

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  Qt.include("three.js")
  Qt.include("threex.planets.js")

  var SUN = 0;
  var MERCURY = 1;
  var VENUS = 2;
  var EARTH = 3;
  var MARS = 4;
  var JUPITER = 5;
  var SATURN = 6;
  var URANUS = 7;
  var NEPTUNE = 8;
  var NUM_SELECTABLE_PLANETS = 9;
  var MOON = 9;
  var SOLAR_SYSTEM = 100;

  var camera, scene, renderer;
  var planetCanvas, mouse, raycaster;

  var daysPerFrame;
  var daysPerFrameScale;
  var planetScale;
  var cameraDistance;

  var objects = []; // Planet objects
  var hitObjects = []; // Planet hit detection objects
  var planets = []; // Planet data info

  var commonGeometry;
  var hitGeometry;
  var solarDistance = 2600000;
  var saturnOuterRadius = 120.700;
  var uranusOuterRadius = 40;

  var qmlView;

  var oldFocusedPlanetPosition;
  var oldCameraPosition;
  var defaultCameraPosition;

  var y = 2000;
  var m = 1;
  var D = 1;
  // Time scale formula based on http://www.stjarnhimlen.se/comp/ppcomp.html
  var startD = 367 * y - 7 * (y + (m + 9) / 12) / 4 + 275 * m / 9 + D - 730530;
  var oldTimeD = startD;
  var currTimeD = startD;

  var auScale = 149597.870700; // AU in thousands of kilometers

  var focusedScaling = false;
  var focusedMinimumScale = 20;
  var actualScale;

  function initializeGL(canvas, eventSource, mainView) {

      planetCanvas = canvas;
      qmlView = mainView;

      camera = new THREE.PerspectiveCamera(45, canvas.width / canvas.height, 2500000, 20000000);
      defaultCameraPosition = new THREE.Vector3(solarDistance, solarDistance, solarDistance);
      camera.position.set(defaultCameraPosition.x, defaultCameraPosition.y, defaultCameraPosition.z);

      scene = new THREE.Scene();

      var starSphere = THREEx.Planets.createStarfield(8500000);
      scene.add(starSphere);

      var light = new THREE.PointLight(0x777777, 2);
      light.position.set(0, 0, 0);
      scene.add(light);

      scene.add(new THREE.AmbientLight(0x111111));

      loadPlanetData();
      createPlanets();
      setScale(1200);

      camera.lookAt(objects[0].position); // look at the Sun

      raycaster = new THREE.Raycaster();
      mouse = new THREE.Vector2();

      renderer = new THREE.Canvas3DRenderer(
                  { canvas: canvas, antialias: true, devicePixelRatio: canvas.devicePixelRatio });

      renderer.setPixelRatio(canvas.devicePixelRatio);
      renderer.setSize(canvas.width, canvas.height);
      eventSource.mouseDown.connect(onDocumentMouseDown);
  }

  function loadPlanetData() {

      // Planet Data
      // radius - planet radius in millions of meters
      // tilt - planet axis angle
      // N1 N2 - longitude of the ascending node
      // i1 i2 - inclination to the ecliptic (plane of the Earth's orbit)
      // w1 w2 - argument of perihelion
      // a1 a2 - semi-major axis, or mean distance from Sun
      // e1 e2 - eccentricity (0=circle, 0-1=ellipse, 1=parabola)
      // M1 M2 - mean anomaly (0 at perihelion; increases uniformly with time)
      // period - sidereal rotation period
      // centerOfOrbit - the planet in the center of the orbit
      // (orbital elements based on http://www.stjarnhimlen.se/comp/ppcomp.html)

      var sun = { radius: 694.439, tilt: 63.87, period: 25.05 };
      planets.push(sun);
      var mercury = {
          radius: 2.433722, tilt: 0.04, N1: 48.3313, N2: 0.0000324587,
          i1: 7.0047, i2: 0.0000000500, w1: 29.1241, w2: 0.0000101444,
          a1: 0.387098, a2: 0, e1: 0.205635, e2: 0.000000000559,
          M1: 168.6562, M2: 4.0923344368, period: 58.646,
          centerOfOrbit: SUN
      };
      planets.push(mercury);
      var venus = {
          radius: 6.046079, tilt: 177.36, N1: 76.6799, N2: 0.0000246590,
          i1: 3.3946, i2: 0.0000000275, w1: 54.8910, w2: 0.0000138374,
          a1: 0.723330, a2: 0, e1: 0.006773, e2: -0.000000001302,
          M1: 48.0052, M2: 1.6021302244, period: 243.0185,
          centerOfOrbit: SUN
      };
      planets.push(venus);
      var earth = {
          radius: 6.371, tilt: 25.44, N1: 174.873, N2: 0,
          i1: 0.00005, i2: 0, w1: 102.94719, w2: 0,
          a1: 1, a2: 0, e1: 0.01671022, e2: 0,
          M1: 357.529, M2: 0.985608, period: 0.997,
          centerOfOrbit: SUN
      };
      planets.push(earth);
      var mars = {
          radius: 3.389372, tilt: 25.19, N1: 49.5574, N2: 0.0000211081,
          i1: 1.8497, i2: -0.0000000178, w1: 286.5016, w2: 0.0000292961,
          a1: 1.523688, a2: 0, e1: 0.093405, e2: 0.000000002516,
          M1: 18.6021, M2: 0.5240207766, period: 1.025957,
          centerOfOrbit: SUN
      };
      planets.push(mars);
      var jupiter = {
          radius: 71.41254, tilt: 3.13, N1: 100.4542, N2: 0.0000276854,
          i1: 1.3030, i2: -0.0000001557, w1: 273.8777, w2: 0.0000164505,
          a1: 5.20256, a2: 0, e1: 0.048498, e2: 0.000000004469,
          M1: 19.8950, M2: 0.0830853001, period: 0.4135,
          centerOfOrbit: SUN
      };
      planets.push(jupiter);
      var saturn = {
          radius: 60.19958, tilt: 26.73, N1: 113.6634, N2: 0.0000238980,
          i1: 2.4886, i2: -0.0000001081, w1: 339.3939, w2: 0.0000297661,
          a1: 9.55475, a2: 0, e1: 0.055546, e2: -0.000000009499,
          M1: 316.9670, M2: 0.0334442282, period: 0.4395,
          centerOfOrbit: SUN
      };
      planets.push(saturn);
      var uranus = {
          radius: 25.5286, tilt: 97.77, N1: 74.0005, N2: 0.000013978,
          i1: 0.7733, i2: 0.000000019, w1: 96.6612, w2: 0.000030565,
          a1: 19.18171, a2: -0.0000000155, e1: 0.047318, e2: 0.00000000745,
          M1: 142.5905, M2: 0.011725806, period: 0.71833,
          centerOfOrbit: SUN
      };
      planets.push(uranus);
      var neptune = {
          radius: 24.73859, tilt: 28.32, N1: 131.7806, N2: 0.000030173,
          i1: 1.7700, i2: -0.000000255, w1: 272.8461, w2: 0.000006027,
          a1: 30.05826, a2: 0.00000003313, e1: 0.008606, e2: 0.00000000215,
          M1: 260.2471, M2: 0.005995147, period: 0.6713,
          centerOfOrbit: SUN
      };
      planets.push(neptune);
      var moon = {
          radius: 1.5424, tilt: 28.32, N1: 125.1228, N2: -0.0529538083,
          i1: 5.1454, i2: 0, w1: 318.0634, w2: 0.1643573223,
          a1: 0.273, a2: 0, e1: 0.054900, e2: 0,
          M1: 115.3654, M2: 13.0649929509, period: 27.321582,
          centerOfOrbit: EARTH
      };
      planets.push(moon);

  }

  function createPlanets() {

      objects = [];

      commonGeometry = new THREE.BufferGeometry().fromGeometry(new THREE.SphereGeometry(1, 64, 64));
      hitGeometry = new THREE.BufferGeometry().fromGeometry(new THREE.SphereGeometry(1, 8, 8));

      var ringSegments = 70;
      var mesh, innerRadius, outerRadius, ring;

      for (var i = 0; i < planets.length; i ++) {
          switch (i) {
          case SUN:
              mesh = createSun(planets[i]["radius"]);
              mesh.position.set(0, 0, 0);
              break;
          case MERCURY:
              mesh = createPlanet(planets[i]["radius"], 0.005, 'images/mercurymap.jpg',
                                  'images/mercurybump.jpg');
              break;
          case VENUS:
              mesh = createPlanet(planets[i]["radius"], 0.005, 'images/venusmap.jpg',
                                  'images/venusbump.jpg');
              break;
          case EARTH:
              mesh = createPlanet(planets[i]["radius"], 0.05, 'images/earthmap1k.jpg',
                                  'images/earthbump1k.jpg', 'images/earthspec1k.jpg');
              createEarthCloud(mesh);
              break;
          case MARS:
              mesh = createPlanet(planets[i]["radius"], 0.05, 'images/marsmap1k.jpg',
                                  'images/marsbump1k.jpg');
              break;
          case JUPITER:
              mesh = createPlanet(planets[i]["radius"], 0.02, 'images/jupitermap.jpg',
                                  'images/jupitermap.jpg');
              break;
          case SATURN:
              mesh = createPlanet(planets[i]["radius"], 0.05, 'images/saturnmap.jpg',
                                  'images/saturnmap.jpg');
              innerRadius = (planets[i]["radius"] + 6.630) / planets[i]["radius"];
              outerRadius = (planets[i]["radius"] + saturnOuterRadius) / planets[i]["radius"];
              ring = createRing(innerRadius, outerRadius, ringSegments,
                                    'qrc:images/saturnringcolortrans.png');
              ring.receiveShadow = true;
              ring.castShadow = true;
              mesh.add(ring);
              break;
          case URANUS:
              mesh = createPlanet(planets[i]["radius"], 0.05, 'images/uranusmap.jpg',
                                  'images/uranusmap.jpg');
              innerRadius = (planets[i]["radius"] + 2) / planets[i]["radius"];
              outerRadius = (planets[i]["radius"] + uranusOuterRadius) / planets[i]["radius"];
              ring = createRing(innerRadius, outerRadius, ringSegments,
                                    'qrc:images/uranusringcolortrans.png');
              ring.receiveShadow = true;
              ring.castShadow = true;
              mesh.add(ring);
              break;
          case NEPTUNE:
              mesh = createPlanet(planets[i]["radius"], 0.05, 'images/neptunemap.jpg',
                                  'images/neptunemap.jpg');
              break;
          case MOON:
              mesh = createPlanet(planets[i]["radius"], 0.05, 'images/moonmap1k.jpg',
                                  'images/moonbump1k.jpg');
              break;
          }

          objects.push(mesh);
          scene.add(mesh);

          // Create separate meshes for click detection
          var hitMesh = new THREE.Mesh(hitGeometry);
          hitMesh.visible = false;
          hitObjects.push(hitMesh);
          scene.add(hitMesh);
      }

  }

  function createSun(radius) {

      var textureLoader = new THREE.TextureLoader();
      var texture = textureLoader.load('images/sunmap.jpg');
      var material = new THREE.MeshBasicMaterial({ map: texture });
      var mesh = new THREE.Mesh(commonGeometry, material);
      mesh.scale.set(radius, radius, radius);

      mesh.receiveShadow = false;
      mesh.castShadow = false;

      return mesh;
  }

  function createPlanet(radius, bumpMapScale, mapTexture, bumpTexture, specularTexture) {

      var textureLoader = new THREE.TextureLoader();
      var material = new THREE.MeshPhongMaterial({
                                                     map: textureLoader.load(mapTexture),
                                                     bumpMap: textureLoader.load(bumpTexture),
                                                     bumpScale: bumpMapScale
                                                 });

      if (specularTexture) {
          material.specularMap = textureLoader.load(specularTexture);
          material.specular = new THREE.Color('grey');
          material.shininess = 50.0;
      } else {
          material.shininess = 1.0;
      }

      var mesh = new THREE.Mesh(commonGeometry, material);
      mesh.scale.set(radius, radius, radius);

      return mesh;

  }

  function createEarthCloud(earthMesh) {

      var textureLoader = new THREE.TextureLoader();
      var material = new THREE.MeshPhongMaterial({
                                                     map: textureLoader.load('qrc:images/earthcloudmapcolortrans.png'),
                                                     side: THREE.BackSide,
                                                     transparent: true,
                                                     opacity: 0.8
                                                 });
      var mesh = new THREE.Mesh(commonGeometry, material);

      var material2 = new THREE.MeshPhongMaterial({
                                                     map: textureLoader.load('qrc:images/earthcloudmapcolortrans.png'),
                                                     side: THREE.FrontSide,
                                                     transparent: true,
                                                     opacity: 0.8
                                                 });
      var mesh2 = new THREE.Mesh(commonGeometry, material2);

      mesh.scale.set(1.02, 1.02, 1.02);
      earthMesh.add(mesh);
      mesh2.scale.set(1.02, 1.02, 1.02);
      earthMesh.add(mesh2);
  }

  function createRing(radius, width, height, texture) {

      var textureLoader = new THREE.TextureLoader();
      var geometry = new THREE.BufferGeometry().fromGeometry(
                  new THREEx.Planets._RingGeometry(radius, width, height));

      var material = new THREE.MeshPhongMaterial({
                                                     map: textureLoader.load(texture),
                                                     side: THREE.DoubleSide,
                                                     transparent: true,
                                                     opacity: 0.8
                                                 });
      material.map.minFilter = THREE.NearestFilter;
      var mesh = new THREE.Mesh(geometry, material);
      mesh.lookAt(new THREE.Vector3(0, 90, 0));

      return mesh;

  }

  function createStarfield(radius) {

      var textureLoader = new THREE.TextureLoader();
      var texture = textureLoader.load('images/galaxy_starfield.png')
      var material = new THREE.MeshBasicMaterial({
                                                     map: texture,
                                                     side: THREE.BackSide
                                                 })
      var geometry = new THREE.BufferGeometry().fromGeometry(new THREE.SphereGeometry(radius, 32, 32));
      var mesh = new THREE.Mesh(geometry, material)

      return mesh

  }

  function onResizeGL(canvas) {

      if (camera === undefined) return;

      camera.aspect = canvas.width / canvas.height;
      camera.updateProjectionMatrix();
      renderer.setPixelRatio(canvas.devicePixelRatio);
      renderer.setSize(canvas.width, canvas.height);

  }

  function onSpeedChanged(value) {

      daysPerFrameScale = value;

  }

  function setScale(value, focused) {

      // Save actual scale in focus mode
      if (!focused)
          actualScale = value;

      // Limit minimum scaling in focus mode to avoid jitter caused by rounding errors
      if (value <= focusedMinimumScale && (focusedScaling || focused)) {
          planetScale = focusedMinimumScale;
      } else {
          planetScale = actualScale;
      }

      for (var i = 0; i < objects.length; i++) {
          var object = objects[i];
          // first reset scale
          var radius = planets[i]["radius"];
          object.scale.set(radius, radius, radius);
          if (i === SUN) {
              object.scale.multiplyScalar(planetScale / 100);
          } else {
              object.scale.multiplyScalar(planetScale);
          }
          hitObjects[i].scale.set(object.scale.x, object.scale.y, object.scale.z);
      }

  }

  function prepareFocusedPlanetAnimation() {

      oldCameraPosition = camera.position.clone();

      var planet = SUN;
      if (qmlView.oldPlanet !== SOLAR_SYSTEM)
          planet = qmlView.oldPlanet;
      oldFocusedPlanetPosition = objects[planet].position.clone();
      qmlView.oldPlanet = qmlView.focusedPlanet;

      if (qmlView.focusedPlanet !== SOLAR_SYSTEM && actualScale <= focusedMinimumScale) {
          // Limit minimum scaling in focus mode to avoid jitter caused by rounding errors
          planetScale = focusedMinimumScale;
          setScale(focusedMinimumScale, true);
          focusedScaling = true;
      } else if (focusedScaling === true) {
          // Restore normal scaling
          focusedScaling = false;
          setScale(actualScale);
      }

      calculateLookAtOffset();
      calculateCameraOffset();

  }

  function setCameraDistance(distance) {

      cameraDistance = distance;

  }

  function calculateLookAtOffset() {

      var offset = oldFocusedPlanetPosition.clone();

      var planet = 0;
      if (qmlView.focusedPlanet !== SOLAR_SYSTEM)
          planet = qmlView.oldPlanet;

      var focusedPlanetPosition = objects[planet].position.clone();
      offset.sub(focusedPlanetPosition);

      qmlView.xLookAtOffset = offset.x;
      qmlView.yLookAtOffset = offset.y;
      qmlView.zLookAtOffset = offset.z;

  }

  function calculateCameraOffset() {

      var offset = oldCameraPosition.clone();

      var planet = 0;
      if (qmlView.focusedPlanet !== SOLAR_SYSTEM)
          planet = qmlView.focusedPlanet;

      var newCameraPosition = getNewCameraPosition(getOuterRadius(planet));

      if (qmlView.focusedPlanet !== SUN)
          offset.sub(newCameraPosition);

      if (qmlView.focusedPlanet === SUN && qmlView.oldPlanet === SOLAR_SYSTEM) {
          qmlView.xCameraOffset = Math.abs(offset.x);
          qmlView.yCameraOffset = Math.abs(offset.y);
          qmlView.zCameraOffset = Math.abs(offset.z);
      } else { // from a planet to another
          qmlView.xCameraOffset = offset.x;
          qmlView.yCameraOffset = offset.y;
          qmlView.zCameraOffset = offset.z;
      }

  }

  function getNewCameraPosition( radius ) {

      var position;
      if (qmlView.focusedPlanet === SOLAR_SYSTEM) {
          position = defaultCameraPosition.clone();
          position.multiplyScalar(cameraDistance);
      } else if (qmlView.focusedPlanet === SUN) {
          position = new THREE.Vector3(radius * planetScale * 2,
                                       radius * planetScale * 2,
                                       radius * planetScale * 2);
          position.multiplyScalar(cameraDistance);

      } else {
          var vec1 = objects[qmlView.focusedPlanet].position.clone();
          var vec2 = new THREE.Vector3(0, 1, 0);
          vec1.normalize();
          vec2.cross(vec1);
          vec2.multiplyScalar(radius * planetScale * cameraDistance * 4);
          vec2.add(objects[qmlView.focusedPlanet].position);
          vec1.set(0, radius * planetScale, 0);
          vec2.add(vec1);
          position = vec2;
      }
      return position;
  }

  function onDocumentMouseDown(x, y) {

      // Mouse selection for planets and Solar system, not for the Moon.
      // Intersection tests are done against a set of cruder hit objects instead of
      // actual planet meshes, as checking a lot of faces can be slow.
      mouse.set((x / planetCanvas.width) * 2 - 1, - (y / planetCanvas.height ) * 2 + 1);

      raycaster.setFromCamera(mouse, camera);

      var intersects = [];
      var i = 0;
      var objectCount = hitObjects.length - 1; // -1 excludes the moon, which is the last object
      while (i < objectCount) {
          // Update hitObject position
          var objectPos = objects[i].position;
          var hitObject = hitObjects[i];
          hitObject.position.set(objectPos.x, objectPos.y, objectPos.z);
          hitObject.updateMatrixWorld();

          hitObject.raycast( raycaster, intersects );

          i++;
      }
      intersects.sort( raycaster.ascSort );

      var selectedPlanet;

      if (intersects.length > 0) {
          var intersect = intersects[0];

          i = 0;
          while (i < objectCount) {
              if (intersect.object === hitObjects[i]) {
                  selectedPlanet = i;
                  break;
              }
              i++;
          }
          if (selectedPlanet < NUM_SELECTABLE_PLANETS) {
              qmlView.focusedPlanet = selectedPlanet;
              // Limit minimum scaling in focus mode to avoid jitter caused by rounding errors
              if (actualScale <= focusedMinimumScale) {
                  planetScale = focusedMinimumScale;
                  setScale(focusedMinimumScale, true);
              }
              focusedScaling = true;
          }
      } else {
          qmlView.focusedPlanet = SOLAR_SYSTEM;
          // Restore normal scaling
          if (focusedScaling === true) {
              focusedScaling = false;
              setScale(actualScale);
          }
      }

  }

  function paintGL(canvas) {

      if (qmlView.focusedPlanet === SOLAR_SYSTEM)
          daysPerFrame = daysPerFrameScale * 10;
      else
          daysPerFrame = daysPerFrameScale * planets[qmlView.focusedPlanet]["period"] / 100;

      // Advance the time in days
      oldTimeD = currTimeD;
      currTimeD = currTimeD + daysPerFrame;
      var deltaTimeD = currTimeD - oldTimeD;

      // Position the planets orbiting the sun
      for (var i = 1; i < objects.length; i ++) {
          var object = objects[i];
          var planet = planets[i];

          // Bumpmaps of mercury, venus, jupiter and moon need special handling
          if (i == MERCURY || i == VENUS || i == JUPITER || i == MOON)
              object.material.bumpScale = 0.03 * planetScale;
          else
              object.material.bumpScale = 0.3 * planetScale;

          // Calculate the planet orbital elements from the current time in days
          var N =  (planet["N1"] + planet["N2"] * currTimeD) * Math.PI / 180;
          var iPlanet = (planet["i1"] + planet["i2"] * currTimeD) * Math.PI / 180;
          var w =  (planet["w1"] + planet["w2"] * currTimeD) * Math.PI / 180;
          var a = planet["a1"] + planet["a2"] * currTimeD;
          var e = planet["e1"] + planet["e2"] * currTimeD;
          var M = (planet["M1"] + planet["M2"] * currTimeD) * Math.PI / 180;
          var E = M + e * Math.sin(M) * (1.0 + e * Math.cos(M));

          var xv = a * (Math.cos(E) - e);
          var yv = a * (Math.sqrt(1.0 - e * e) * Math.sin(E));
          var v = Math.atan2(yv, xv);

          // Calculate the distance (radius)
          var r = Math.sqrt(xv * xv + yv * yv);

          // From http://www.davidcolarusso.com/astro/
          // Modified to compensate for the right handed coordinate system of OpenGL
          var xh = r * (Math.cos(N) * Math.cos(v + w)
                        - Math.sin(N) * Math.sin(v + w) * Math.cos(iPlanet));
          var zh = -r * (Math.sin(N) * Math.cos(v + w)
                         + Math.cos(N) * Math.sin(v + w) * Math.cos(iPlanet));
          var yh = r * (Math.sin(w + v) * Math.sin(iPlanet));

          // Apply the position offset from the center of orbit to the bodies
          var centerOfOrbit = objects[planet["centerOfOrbit"]];
          object.position.set(centerOfOrbit.position.x + xh * auScale,
                              centerOfOrbit.position.y + yh * auScale,
                              centerOfOrbit.position.z + zh * auScale);

          // Calculate and apply the appropriate axis tilt to the bodies
          // and rotate them around the axis
          var radians = planet["tilt"] * Math.PI / 180; // tilt in radians
          object.rotation.order = 'ZXY';
          object.rotation.x = 0;
          object.rotation.y += (deltaTimeD / planet["period"]) * 2 * Math.PI;
          object.rotation.z = radians;
      }

      // rotate the Sun
      var sun = objects[SUN];
      sun.rotation.order = 'ZXY';
      sun.rotation.x = 0;
      sun.rotation.y += (deltaTimeD / planets[SUN]["period"]) * 2 * Math.PI;
      sun.rotation.z = planets[SUN]["tilt"] * Math.PI / 180; // tilt in radians

      // calculate the outer radius of the focused item
      var outerRadius = getOuterRadius(qmlView.focusedPlanet);

      // get the appropriate near plane position for the camera and animate it with QML animations
      qmlView.cameraNear = outerRadius;

      camera.near = qmlView.cameraNear;
      camera.updateProjectionMatrix();

      // Calculate and set camera position
      var cameraPosition = getNewCameraPosition(outerRadius);
      var cameraOffset = new THREE.Vector3(qmlView.xCameraOffset,
                                           qmlView.yCameraOffset,
                                           qmlView.zCameraOffset);
      cameraPosition.add(cameraOffset);
      camera.position.set(cameraPosition.x, cameraPosition.y, cameraPosition.z);

      // Calculate and set camera look-at point
      var lookAtPlanet = SUN;
      if (qmlView.focusedPlanet !== SOLAR_SYSTEM)
          lookAtPlanet = qmlView.focusedPlanet;
      var cameraLookAt = objects[lookAtPlanet].position.clone();
      var lookAtOffset = new THREE.Vector3(qmlView.xLookAtOffset,
                                           qmlView.yLookAtOffset,
                                           qmlView.zLookAtOffset);
      cameraLookAt.add(lookAtOffset);
      camera.lookAt(cameraLookAt);

      // Render the scene
      renderer.render(scene, camera);

  }

  function getOuterRadius( planet ) {

      var outerRadius = solarDistance;
      if (planet !== SOLAR_SYSTEM) {
          outerRadius = planets[planet]["radius"];
          if (planet === SATURN) {
              outerRadius =+ saturnOuterRadius;
          } else if (planet === URANUS) {
              outerRadius =+ uranusOuterRadius;
          } else if (planet === SUN) {
              outerRadius = planets[planet]["radius"] / 100;
          }
      }

      return outerRadius;
  }