src/Computer/ThermalBandComputer.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 "ThermalBandComputer.hpp"
  25 #include "NMEA/MoreData.hpp"
  26 #include "NMEA/Derived.hpp"
  27 #include "Settings.hpp"
  28
  29 void
  30 ThermalBandComputer::Reset()
  31 {
  32   last_vario_available.Clear();
  33 }
  34
  35 void
  36 ThermalBandComputer::Compute(const MoreData &basic,
  37                              const DerivedInfo &calculated,
  38                              ThermalBandInfo &tbi,
  39                              const ComputerSettings &settings)
  40 {
  41   if (!basic.NavAltitudeAvailable())
  42     return;
  43
  44   const fixed h_safety =
  45     settings.task.route_planner.safety_height_terrain +
  46     calculated.GetTerrainBaseFallback();
  47
  48   tbi.working_band_height = basic.TE_altitude - h_safety;
  49   if (negative(tbi.working_band_height)) {
  50     tbi.working_band_fraction = fixed(0);
  51     return;
  52   }
  53
  54   const fixed max_height = tbi.max_thermal_height;
  55   if (positive(max_height))
  56     tbi.working_band_fraction = tbi.working_band_height / max_height;
  57   else
  58     tbi.working_band_fraction = fixed(1);
  59
  60   tbi.working_band_ceiling = std::max(max_height + h_safety,
  61                                       basic.TE_altitude);
  62
  63
  64   last_vario_available.FixTimeWarp(basic.brutto_vario_available);
  65   if (basic.brutto_vario_available.Modified(last_vario_available)) {
  66     last_vario_available = basic.brutto_vario_available;
  67
  68     // JMW TODO accuracy: Should really work out dt here,
  69     //           but i'm assuming constant time steps
  70
  71     if (tbi.max_thermal_height == fixed(0))
  72       tbi.max_thermal_height = tbi.working_band_height;
  73
  74     // only do this if in thermal and have been climbing
  75     if (calculated.circling && calculated.turning &&
  76         positive(calculated.average))
  77       tbi.Add(tbi.working_band_height, basic.brutto_vario);
  78   }
  79 }