/**************************************************************************\
 *
 *  This file is part of the Coin 3D visualization library.
 *  Copyright (C) 1998-2002 by Systems in Motion. All rights reserved.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  version 2.1 as published by the Free Software Foundation. See the
 *  file LICENSE.LGPL at the root directory of the distribution for
 *  more details.
 *
 *  If you want to use Coin for applications not compatible with the
 *  LGPL, please contact SIM to acquire a Professional Edition license.
 *
 *  Systems in Motion, Prof Brochs gate 6, 7030 Trondheim, NORWAY
 *  http://www.sim.no support@sim.no Voice: +47 22114160 Fax: +47 22207097
 *
\**************************************************************************/

#ifndef COIN_SOGATE_H
#define COIN_SOGATE_H

#include <Inventor/engines/SoSubEngine.h>
#include <Inventor/fields/SoMField.h>
#include <Inventor/fields/SoSFBool.h>
#include <Inventor/fields/SoSFTrigger.h>

class SoEngineOutput;


class COIN_DLL_API SoGate : public SoEngine {
  typedef SoEngine inherited;

  SO_ENGINE_HEADER(SoGate);

public:
  static void initClass(void);
  SoGate(SoType type);

  SoSFBool enable;
  SoSFTrigger trigger;
  SoMField * input;

  SoEngineOutput * output;

protected:
  virtual void inputChanged(SoField * which);

private:
  SoGate(void);
  ~SoGate();

  virtual void evaluate(void);

  virtual SbBool readInstance(SoInput * in, unsigned short flags);
  virtual void writeInstance(SoOutput * out);

  SbBool initialize(const SoType inputfieldtype);

  virtual void copyContents(const SoFieldContainer * from,
                            SbBool copyconnections);

  // SoGate instances uses a dynamic set of inputs and outputs, as
  // they are not common for all instances of the class (like for most
  // of the other engines).
  SoFieldData * dynamicinput;
  SoEngineOutputData * dynamicoutput;

  // Avoid a g++/egcs warning due to the private default constructor.
  friend class dummy;
};

#endif // !COIN_SOGATE_H
