Function morphFrom2DTo3D

packages/engine/Source/Scene/SceneTransitioner.js:470–548

(transitioner, duration, ellipsoid)

const scratch3DToCVEndUp = new Cartesian3();

function morphFrom2DTo3D(transitioner, duration, ellipsoid) {
  duration /= 3.0;

  const scene = transitioner._scene;
  const camera = scene.camera;

  let camera3D;
  if (duration > 0.0) {
    camera3D = scratchCVTo3DCamera;
    Cartesian3.fromDegrees(
      0.0,
      0.0,
      5.0 * ellipsoid.maximumRadius,
      ellipsoid,
      camera3D.position,
    );
    Cartesian3.negate(camera3D.position, camera3D.direction);
    Cartesian3.normalize(camera3D.direction, camera3D.direction);
    Cartesian3.clone(Cartesian3.UNIT_Z, camera3D.up);
  } else {
    camera.position.z = camera.frustum.right - camera.frustum.left;

    camera3D = getColumbusViewTo3DCamera(transitioner, ellipsoid);
  }

  let frustum;
  if (transitioner._morphToOrthographic) {
    frustum = scratch2DTo3DFrustumOrtho;
    frustum.aspectRatio = scene.drawingBufferWidth / scene.drawingBufferHeight;
    frustum.width = camera.frustum.right - camera.frustum.left;
  } else {
    frustum = scratch2DTo3DFrustumPersp;
    frustum.aspectRatio = scene.drawingBufferWidth / scene.drawingBufferHeight;
    frustum.fov = CesiumMath.toRadians(60.0);
  }

  camera3D.frustum = frustum;

  const complete = complete3DCallback(camera3D);
  createMorphHandler(transitioner, complete);

  let morph;
  if (transitioner._morphToOrthographic) {
    morph = function () {
      morphFromColumbusViewTo3D(transitioner, duration, camera3D, complete);
    };
  } else {
    morph = function () {
      morphOrthographicToPerspective(
        transitioner,
        duration,
        camera3D,
        function () {
          morphFromColumbusViewTo3D(transitioner, duration, camera3D, complete);
        },
      );
    };
  }