src/Geo/GeoVector.hpp

   1 /* Copyright_License {
   2
   3   XCSoar Glide Computer - http://www.xcsoar.org/
   4   Copyright (C) 2000-2013 The XCSoar Project
   5   A detailed list of copyright holders can be found in the file "AUTHORS".
   6
   7   This program is free software; you can redistribute it and/or
   8   modify it under the terms of the GNU General Public License
   9   as published by the Free Software Foundation; either version 2
  10   of the License, or (at your option) any later version.
  11
  12   This program is distributed in the hope that it will be useful,
  13   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15   GNU General Public License for more details.
  16
  17   You should have received a copy of the GNU General Public License
  18   along with this program; if not, write to the Free Software
  19   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  20 }
  21  */
  22
  23 #ifndef GEO_VECTOR_HPP
  24 #define GEO_VECTOR_HPP
  25
  26 #include "Math/Angle.hpp"
  27 #include "Compiler.h"
  28
  29 #include <type_traits>
  30
  31 struct GeoPoint;
  32
  33 /**
  34  * A constant bearing vector in lat/lon coordinates.
  35  * Should later be extended to handle
  36  * separately constant bearing and minimum-distance paths.
  37  *
  38  */
  39 struct GeoVector {
  40   /** Distance in meters */
  41   fixed distance;
  42
  43   /** Bearing (true north) */
  44   Angle bearing;
  45
  46   /** Empty non-initializing constructor */
  47   GeoVector() = default;
  48
  49   /** Constructor given supplied distance/bearing */
  50   constexpr
  51   GeoVector(fixed _distance, Angle _bearing)
  52     :distance(_distance), bearing(_bearing) {}
  53
  54   /**
  55    * Constructor given start and end location.
  56    * Computes Distance/Bearing internally.
  57    */
  58   GeoVector(const GeoPoint &source, const GeoPoint &target);
  59
  60   /**
  61    * Create the zero vector: zero distance, undefined bearing.
  62    */
  63   constexpr static GeoVector Zero() {
  64     return GeoVector(fixed(0), Angle::Zero());
  65   }
  66
  67   /**
  68    * Create an invalid instance.
  69    */
  70   constexpr
  71   static GeoVector Invalid() {
  72     return GeoVector(fixed(-1), Angle::Zero());
  73   }
  74
  75   /**
  76    * Returns the end point of the geovector projected from the start point.
  77    * Assumes constant bearing.
  78    */
  79   gcc_pure
  80   GeoPoint EndPoint(const GeoPoint &source) const;
  81
  82   /**
  83    * Returns the end point of the geovector projected from the start point.
  84    * Assumes constand Bearing.
  85    *
  86    * @param source start of vector
  87    * @return location of end point
  88    */
  89   GeoPoint MidPoint(const GeoPoint &source) const;
  90
  91   /**
  92    * Minimum distance from a point on the vector to the reference
  93    *
  94    * @param source Start of vector
  95    * @param ref Point to test
  96    *
  97    * @return Distance (m)
  98    */
  99   gcc_pure
 100   fixed MinimumDistance(const GeoPoint &source, const GeoPoint &ref) const;
 101
 102   constexpr
 103   inline bool IsValid() const {
 104     return !negative(distance);
 105   }
 106
 107   void SetInvalid() {
 108     distance = fixed(-1);
 109   }
 110 };
 111
 112 static_assert(std::is_trivial<GeoVector>::value, "type is not trivial");
 113
 114 #endif