FGSurface.cpp

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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 Module:       FGSurface.cpp
 Author:       Erik Hofman
 Date started: 01/15/14
 Purpose:      Base class for all surface properties
 Called by:    GroundReactions
 
 ------------- Copyright (C) 2014  Jon S. Berndt (jon@jsbsim.org) -------------
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU Lesser 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 Lesser General Public License for more
 details.
 
 You should have received a copy of the GNU Lesser 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.
 
 Further information about the GNU Lesser General Public License can also be found on
 the world wide web at http://www.gnu.org.
 
FUNCTIONAL DESCRIPTION
--------------------------------------------------------------------------------
This base class for the GroundReactions class defines methoed and holds data
for all surface types.
 
HISTORY
--------------------------------------------------------------------------------
01/15/14   EMH   Created
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
#include "input_output/FGPropertyManager.h"
#include "models/FGSurface.h"
 
using namespace std;
 
namespace JSBSim {
 
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS IMPLEMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
 
FGSurface::FGSurface(FGFDMExec* fdmex, int number) :
   contactNumber(number)
{
  _PropertyManager = fdmex->GetPropertyManager();
  resetValues();
}
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
FGSurface::~FGSurface()
{
}
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
void FGSurface::resetValues(void)
{
  staticFFactor = 1.0;
  rollingFFactor = 1.0;
  maximumForce = DBL_MAX;
  bumpiness = 0.0;
  isSolid = true;
  pos[0] = 0.0;
  pos[1] = 0.0;
  pos[2] = 0.0;
}
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
void FGSurface::bind(void)
{
  if (!_PropertyManager) return;
 
  string base_property_name;
  string property_name;
 
  switch(eSurfaceType) {
  case ctBOGEY:
    base_property_name = _CreateIndexedPropertyName("gear/unit", contactNumber);
    break;
  case ctSTRUCTURE:
    base_property_name = _CreateIndexedPropertyName("contact/unit", contactNumber);
    break;
  case ctGROUND:
    base_property_name = "ground";
    break;
  default:
    return;
  }
 
  property_name = base_property_name + "/solid";
  _PropertyManager->Tie( property_name.c_str(), &isSolid);
  property_name = base_property_name + "/bumpiness";
  _PropertyManager->Tie( property_name.c_str(), &bumpiness);
  property_name = base_property_name + "/maximum-force-lbs";
  _PropertyManager->Tie( property_name.c_str(), &maximumForce);
  property_name = base_property_name + "/rolling_friction-factor";
  _PropertyManager->Tie( property_name.c_str(), &rollingFFactor);
  property_name = base_property_name + "/static-friction-factor";
  _PropertyManager->Tie( property_name.c_str(), &staticFFactor);
}
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
float FGSurface::GetBumpHeight()
{
  // bump hight might have been manually set
  if (bumpHeight < DBL_MAX) {
    float rv = bumpHeight;
    bumpHeight = DBL_MAX;
    return rv;
  }
  if (bumpiness < 0.001) return 0.0f;
 
  double x = pos[0]*0.1;
  double y = pos[1]*0.1;
  x -= floor(x);
  y -= floor(y);
  x *= 2*M_PI;
  y *= 2*M_PI;
  //now x and y are in the range of 0..2pi
  //we need a function, that is periodically on 2pi and gives some
  //height. This is not very fast, but for a beginning.
  //maybe this should be done by interpolating between some precalculated
  //values
  static const float maxGroundBumpAmplitude=0.4;
  float h = sin(x)+sin(7*x)+sin(8*x)+sin(13*x);
  h += sin(2*y)+sin(5*y)+sin(9*y*x)+sin(17*y);
 
  return h*(1/8.)*bumpiness*maxGroundBumpAmplitude;
}
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
string FGSurface::_CreateIndexedPropertyName(const string& Property, int index)
{
  std::ostringstream buf;
  buf << Property << '[' << index << ']';
  return buf.str();
}
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
string FGSurface::GetSurfaceStrings(string delimeter) const
{
  std::ostringstream buf;
 
  buf << "staticFFactor" << delimeter
      << "rollingFFactor" << delimeter
      << "maximumForce" << delimeter
      << "bumpiness" << delimeter
      << "isSolid";
  
  return buf.str();
}
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
string FGSurface::GetSurfaceValues(string delimeter) const
{
  std::ostringstream buf;
 
  buf << staticFFactor << delimeter
      << rollingFFactor << delimeter
      << maximumForce << delimeter
      << bumpiness << delimeter
      << (isSolid ? "1" : "0");
 
  return buf.str();
}
 
} // namespace JSBSim