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

 Copyright (C) 2002-2014 Gilles Debunne. All rights reserved.

 This file is part of the QGLViewer library version 2.6.1.

 http://www.libqglviewer.com - contact@libqglviewer.com

 This file may be used under the terms of the GNU General Public License 
 versions 2.0 or 3.0 as published by the Free Software Foundation and
 appearing in the LICENSE file included in the packaging of this file.
 In addition, as a special exception, Gilles Debunne gives you certain 
 additional rights, described in the file GPL_EXCEPTION in this package.

 libQGLViewer uses dual licensing. Commercial/proprietary software must
 purchase a libQGLViewer Commercial License.

 This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

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

#include "keyFrames.h"

#include <QKeyEvent>
#include <QGLViewer/manipulatedFrame.h>

using namespace qglviewer;
using namespace std;

Viewer::Viewer()
  : nbKeyFrames(4)
{
  restoreStateFromFile();

  // myFrame is the Frame that will be interpolated.
  Frame* myFrame = new Frame();

  // Set myFrame as the KeyFrameInterpolator interpolated Frame.
  kfi_.setFrame(myFrame);
  kfi_.setLoopInterpolation();

  // An array of manipulated (key) frames.
  keyFrame_ = new ManipulatedFrame*[nbKeyFrames];

  // Create an initial path
  for (int i=0; i<nbKeyFrames; i++)
	{
	  keyFrame_[i] = new ManipulatedFrame();
	  keyFrame_[i]->setPosition(-1.0 + 2.0*i/(nbKeyFrames-1), 0.0, 0.0);
	  kfi_.addKeyFrame(keyFrame_[i]);
	}

  currentKF_ = 0;
  setManipulatedFrame(keyFrame_[currentKF_]);

  // Enable direct frame manipulation when the mouse hovers.
  setMouseTracking(true);

  setKeyDescription(Qt::Key_Plus, "Increases interpolation speed");
  setKeyDescription(Qt::Key_Minus, "Decreases interpolation speed");
  setKeyDescription(Qt::Key_Left, "Selects previous key frame");
  setKeyDescription(Qt::Key_Right, "Selects next key frame");
  setKeyDescription(Qt::Key_Return, "Starts/stops interpolation");

  help();

  connect(&kfi_, SIGNAL(interpolated()), SLOT(updateGL()));
  kfi_.startInterpolation();
}

QString Viewer::helpString() const
{
  QString text("<h2>K e y F r a m e s</h2>");
  text += "A <i>KeyFrameInterpolator</i> holds an interpolated path defined by key frames. ";
  text += "It can then smoothly make its associed frame follow that path. Key frames can interactively be manipulated, even ";
  text += "during interpolation.<br><br>";
  text += "Note that the camera holds 12 such keyFrameInterpolators, binded to F1-F12. Press <b>Alt+Fx</b> to define new key ";
  text += "frames, and then press <b>Fx</b> to make the camera follow the path. Press <b>C</b> to visualize these paths.<br><br>";
  text += "<b>+/-</b> changes the interpolation speed. Negative values are allowed.<br><br>";
  text += "<b>Return</b> starts-stops the interpolation.<br><br>";
  text += "Use the left and right arrows to change the manipulated KeyFrame. ";
  text += "Press <b>Control</b> to move it or simply hover over it.";
  return text;
}

void Viewer::keyPressEvent(QKeyEvent *e)
{
  switch (e->key())
	{
	case Qt::Key_Left :
	  currentKF_ = (currentKF_+nbKeyFrames-1) % nbKeyFrames;
	  setManipulatedFrame(keyFrame_[currentKF_]);
	  updateGL();
	  break;
	case Qt::Key_Right :
	  currentKF_ = (currentKF_+1) % nbKeyFrames;
	  setManipulatedFrame(keyFrame_[currentKF_]);
	  updateGL();
	  break;
	case Qt::Key_Return :
	  kfi_.toggleInterpolation();
	  break;
	case Qt::Key_Plus :
	  kfi_.setInterpolationSpeed(kfi_.interpolationSpeed()+0.25);
	  break;
	case Qt::Key_Minus :
	  kfi_.setInterpolationSpeed(kfi_.interpolationSpeed()-0.25);
	  break;
	// case Qt::Key_C :
	  // kfi_.setClosedPath(!kfi_.closedPath());
	  // break;
	default:
	  QGLViewer::keyPressEvent(e);
	}
}

void Viewer::draw()
{
  // Draw interpolated frame
  glPushMatrix();
  glMultMatrixd(kfi_.frame()->matrix());
  drawAxis(0.3f);
  glPopMatrix();

  kfi_.drawPath(5, 10);

  for (int i=0; i<nbKeyFrames; ++i)
	{
	  glPushMatrix();
	  glMultMatrixd(kfi_.keyFrame(i).matrix());

	  if ((i == currentKF_) || (keyFrame_[i]->grabsMouse()))
	drawAxis(0.4f);
	  else
	drawAxis(0.2f);

	  glPopMatrix();
	}
}
