Merge pull request #168 from chrisryancombs/m05387

  }

  /**

   * Computes and returns emission angle, in degrees, given the observer

   * position. The surface normal vector is calculated using an ellipsoid, not

   * the local normal of the actual target shape.

   *

   * Emission Angle: The angle between the surface normal vector at the

   * intersection point and the vector from the intersection point to the

   * observer (usually the spacecraft). The emission angle varies from 0 degrees

   * when the observer is viewing the sub-spacecraft point (nadir viewing) to 90

   * degrees when the intercept is tangent to the surface of the target body.

   * Thus, higher values of emission angle indicate more oblique viewing of the

   * target.

   *

   * @param observerBodyFixedPosition  Three dimensional position of the observer,

   *                                   in the coordinate system of the target body.

   *

   * @return The emission angle, in decimal degrees.

   *

   */

  double EmbreeShapeModel::emissionAngle(const std::vector<double> &observerBodyFixedPosition) {

    // If there is already a normal save it, because it's probably the local normal

    std::vector<double> localNormal;

    bool hadNormal = hasNormal();

    if ( hadNormal ) {

      localNormal = normal();

    }

    // Calculate the ellipsoid surface normal

    calculateDefaultNormal();

    // Use ShapeModel to calculate the ellipsoid emission angle

    double ellipsoidEmission = ShapeModel::emissionAngle(observerBodyFixedPosition);

    // If there's a saved normal, reset it

    if ( hadNormal ) {

      setNormal(localNormal);

    }

    // Return the ellipsoid emission angle

    return ellipsoidEmission;

  }

  /**

   * Computes and returns incidence angle, in degrees, given the illuminator position.

   * The surface normal vector is calculated using an ellipsoid, not the local

   *

   * @internal

   *   @history 2017-04-22 Jesse Mapel and Jeannie Backer - Original Version

   *   @history 2018-05-01 Christopher Combs - Removed emissionAngle function to

   *                fix issues with using ellipsoids to find normals. Fixes #5387.

   */

  class EmbreeShapeModel : public ShapeModel {

    public:

      virtual void calculateSurfaceNormal();

      QVector<double> ellipsoidNormal();

      virtual double emissionAngle(const std::vector<double> &sB);

      virtual double incidenceAngle(const std::vector<double> &uB);

      virtual Distance localRadius(const Latitude &lat, const Longitude &lon);

      // Determine if the internal intercept is occluded from the observer/lookdir