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

 Copyright (C) 2002-2006 Gilles Debunne (Gilles.Debunne@imag.fr)

This file is part of the QGLViewer library.
 Version 2.2.4-1, released on December 12, 2006.

 http://artis.imag.fr/Members/Gilles.Debunne/QGLViewer

 libQGLViewer 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.

 libQGLViewer 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 libQGLViewer; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

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

#include "viewer.h"
#include "standardCamera.h"

using namespace std;
using namespace qglviewer;

Viewer::Viewer(StandardCamera* nfc)
{
  // Change the camera.
  Camera* c = camera();
  setCamera(nfc);
  delete c;
}

// Draws a spiral
void Viewer::draw()
{
  const float nbSteps = 200.0;

  glBegin(GL_QUAD_STRIP);
  for (int i=0; i<nbSteps; ++i)
    {
      const float ratio = i/nbSteps;
      const float angle = 21.0f*ratio;
      const float c = cos(angle);
      const float s = sin(angle);
      const float r1 = 1.0f - 0.8f*ratio;
      const float r2 = 0.8f - 0.8f*ratio;
      const float alt = ratio - 0.5f;
      const float nor = 0.5f;
      const float up = sqrt(1.0f-nor*nor);
      glColor3f(1.0f-ratio, 0.2f , ratio);
      glNormal3f(nor*c, up, nor*s);
      glVertex3f(r1*c, alt, r1*s);
      glVertex3f(r2*c, alt+0.05f, r2*s);
    }
  glEnd();
}

void Viewer::init()
{
  // Restore previous viewer state.
  if (!restoreStateFromFile())
  showEntireScene();

  setKeyDescription(Qt::Key_T, "Toggles camera type (perspective or orthographic)");
  setKeyDescription(Qt::Key_M, "Toggles camera mode (standard or QGLViewer)");

  // Display help window.
  help();
}

void Viewer::showMessage()
{
  QString std = ((StandardCamera*)camera())->isStandard()?"Standard camera":"QGLViewer camera";
  QString type = camera()->type() == Camera::PERSPECTIVE?"Perspective":"Orthogonal";
  displayMessage(std + " - " + type);
  emit cameraChanged();
}

void Viewer::keyPressEvent(QKeyEvent *e)
{
  if (e->key() == Qt::Key_M) {
  // 'M' changes mode : standard or QGLViewer camera
    ((StandardCamera*)camera())->toggleMode();
    showMessage();
  } else
    if (e->key() == Qt::Key_T) {
    // 'T' changes the projection type : perspective or orthogonal
      if (camera()->type() == Camera::ORTHOGRAPHIC)
        camera()->setType(Camera::PERSPECTIVE);
      else
        camera()->setType(Camera::ORTHOGRAPHIC);
        showMessage();
      } else
        QGLViewer::keyPressEvent(e);
}

void Viewer::wheelEvent(QWheelEvent *e)
{
  if ((camera()->type() == Camera::ORTHOGRAPHIC) && (((StandardCamera*)camera())->isStandard()) &&
#if QT_VERSION >= 0x040000
    (e->modifiers() & Qt::ShiftModifier))
#else
    (e->state() & Qt::ShiftButton))
#endif
  {
    ((StandardCamera*)camera())->changeOrthoFrustumSize(e->delta());
    emit cameraChanged();
    updateGL();
  }
  else
    QGLViewer::wheelEvent(e);
}

QString Viewer::helpString() const
{
  QString text("<h2>S t a n d a r d C a m e r a</h2>");
  text += "An overloaded <code>Camera</code> class is used, that reproduces the 'standard' OpenGL settings.<br><br>";

  text += "With this camera, the near and (resp. far) plane distance is set to a very small (resp. very large) value. ";
  text += "With the orthographic camera type, the frustum dimensions are fixed. Use <code>Shift</code> and the mouse wheel to change them.<br><br>";

  text += "On the other hand, the QGLViewer camera fits the near and far distances to the scene radius. ";
  text += "Fine tuning is available using <code>zClippingCoefficient()</code> and <code>zNearCoefficient()</code>. ";
  text += "However, visual results do not seem to be impacted by this zBuffer fitted range.<br><br>";
  text += "The QGLViewer camera also adapts the orthographic frustum dimensions to the distance to the <code>revolveAroundPoint()</code> to mimic a perspective camera. ";
  text += "Since this behavior may not be needed, this example shows how to override it.<br><br>";

  text += "The second viewer displays the first one's camera to show its configuration.<br><br>";

  text += "Use <b>M</b> to switch between 'standard' and QGLViewer camera behavior.<br>";
  text += "Use <b>T</b> to switch between perspective and orthographic camera type.";

  return text;
}