Add initial Spherical struct

include/Spherical.h

@@ -0,0 +1,38 @@
+/// @copyright
+/// This Source Code Form is subject to the terms of the Mozilla Public
+/// License, v. 2.0.If a copy of the MPL was not distributed with this
+/// file, You can obtain one at https ://mozilla.org/MPL/2.0/.
+
+#ifndef SPHERICAL_H
+#define SPHERICAL_H
+
+/// @brief A spherical vector
+/// @details
+/// This is a vector in 3D space using a spherical coordinate system.
+/// It consists of a distance and the polar and elevation angles from a
+/// reference direction. The reference direction is typically thought of
+/// as a forward direction.
+struct Spherical {
+ public:
+  /// @brief The angle in the horizontal plane in degrees, clockwise rotation
+  /// @details The angle is automatically normalized to -180 .. 180
+  float polarAngle;
+  /// @brief The angle in the vertical plane in degrees. Positive is upward.
+  /// @details The angle is automatically normalized to -180 .. 180
+  float elevationAngle;
+
+  /// @brief Create a new spherical vector with zero degrees and distance
+  Spherical();
+  /// @brief Create a new spherical vector
+  /// @param polarAngle The angle in the horizontal plane in degrees,
+  /// clockwise rotation
+  /// @param elevationAngle The angle in the vertical plan in degrees,
+  /// zero is forward, positive is upward
+  /// @param distance The distance in meters
+  Spherical(float polarAngle, float elevationAngle, float distance);
+
+  /// @brief A spherical vector with zero degree angles and distance
+  const static Spherical zero;
+};
+
+#endif