// @configure_input@

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 * modification, are permitted provided that the following conditions are
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 * this list of conditions and the following disclaimer.
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 * notice, this list of conditions and the following disclaimer in the
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
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// This file contains the generic, "templatize-able" parts of the
// So*WalkViewer source code.

// *************************************************************************

/*!
  \class So@Gui@WalkViewer Inventor/@Gui@/viewers/So@Gui@WalkViewer.h
  \brief The So@Gui@WalkViewer class is a viewer for moving about in "walk"-like style.

  \ingroup components viewers

  This is a viewer suitable for architectural-type walk-throughs, for
  instance.

  FIXME: more class doc
*/

// *************************************************************************

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif // HAVE_CONFIG_H

#include <Inventor/@Gui@/viewers/So@Gui@WalkViewer.h>
#include <Inventor/@Gui@/viewers/SoGuiWalkViewerP.h>
#include <Inventor/SbLinear.h>
#include <Inventor/errors/SoDebugError.h>
#include <Inventor/nodes/SoCamera.h>
#include <cassert>
#include <so@gui@defs.h>

#define PRIVATE(ptr) ptr->pimpl
#define PUBLIC(ptr) ptr->pub

#ifndef DOXYGEN_SKIP_THIS

SoGuiWalkViewerP::SoGuiWalkViewerP(So@Gui@WalkViewer * publ)
{
  PUBLIC(this) = publ;
}

SoGuiWalkViewerP::~SoGuiWalkViewerP()
{
}

// This method dollies the camera back and forth in the scene.
void
SoGuiWalkViewerP::dollyCamera(const float delta) const
{
  SoCamera * const camera = PUBLIC(this)->getCamera();
  if (camera == NULL) { return; } // if there's no scene graph, for instance

  SbPlane walkplane(PUBLIC(this)->getUpDirection(), camera->position.getValue());
  SbVec3f campos = camera->position.getValue();
  SbVec3f camvec;
  camera->orientation.getValue().multVec(SbVec3f(0, 0, -1), camvec);
  SbLine cross(campos + camvec,
                campos + camvec + PUBLIC(this)->getUpDirection());
  SbVec3f intersect;
  walkplane.intersect(cross, intersect);
  SbVec3f dir = intersect - campos;
  dir.normalize();

  camera->position = campos - dir * delta;
}

// This method elevates the camera up and down.
void
SoGuiWalkViewerP::elevateCamera(const float delta) const
{
  SoCamera * const camera = PUBLIC(this)->getCamera();
  if (camera == NULL) { return; } // if there's no scene graph, for instance

  SbVec3f up = PUBLIC(this)->getUpDirection();
  up.normalize();
  camera->position = camera->position.getValue() - up * delta;
}

#endif // DOXYGEN_SKIP_THIS

// *************************************************************************

#undef PRIVATE
#undef PUBLIC

