src/Computer/GlideRatioComputer.cpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #include "GlideRatioComputer.hpp"
  25 #include "NMEA/MoreData.hpp"
  26 #include "NMEA/Derived.hpp"
  27
  28 void
  29 GlideRatioComputer::Reset()
  30 {
  31   gr_calculator_initialised = false;
  32 }
  33
  34 void
  35 GlideRatioComputer::Compute(const MoreData &basic, const MoreData &last_basic,
  36                             const DerivedInfo &calculated,
  37                             VarioInfo &vario_info,
  38                             const ComputerSettings &settings)
  39 {
  40   if (!last_basic.location_available ||
  41       !basic.NavAltitudeAvailable() || !last_basic.NavAltitudeAvailable()) {
  42     Reset();
  43     vario_info.gr = INVALID_GR;
  44     vario_info.average_gr = fixed(0);
  45     return;
  46   }
  47
  48   if (!basic.location_available.Modified(last_basic.location_available))
  49     return;
  50
  51   fixed DistanceFlown = basic.location.Distance(last_basic.location);
  52
  53   // Glide ratio over ground
  54   vario_info.gr =
  55     UpdateGR(vario_info.gr, DistanceFlown,
  56              last_basic.nav_altitude - basic.nav_altitude, fixed(0.1));
  57
  58   if (calculated.flight.flying && !calculated.circling) {
  59     if (!gr_calculator_initialised) {
  60       gr_calculator_initialised = true;
  61       gr_calculator.Initialize(settings);
  62     }
  63
  64     gr_calculator.Add((int)DistanceFlown, (int)basic.nav_altitude);
  65     vario_info.average_gr = gr_calculator.Calculate();
  66   } else
  67     gr_calculator_initialised = false;
  68 }