/*
Copyright_License {

  XCSoar Glide Computer - http://www.xcsoar.org/
  Copyright (C) 2000-2013 The XCSoar Project
  A detailed list of copyright holders can be found in the file "AUTHORS".

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation; either version 2
  of the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
}
*/

#ifndef XCSOAR_ATMOSPHERE_AIRDENSITY_H
#define XCSOAR_ATMOSPHERE_AIRDENSITY_H

#include "Math/fixed.hpp"

/**
 * Calculates the air density from a given QNH-based altitude
 * @param altitude QNH-based altitude (m)
 * @return Air density (kg/m^3)
 */
fixed AirDensity(const fixed altitude);

/**
 * Divide TAS by this number to get IAS
 * @param altitude QNH-based altitude (m)
 * @return Ratio of TAS to IAS
 */
fixed AirDensityRatio(const fixed altitude);

#endif
