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

   Copyright (C) 2002-2008 Gilles Debunne. All rights reserved.

   This file is part of the QGLViewer library version 2.3.5.

   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 "manipulatedFrame.h"
#include <math.h>

using namespace qglviewer;
using namespace std;

static void drawSpiral()
{
  const float nbSteps = 200.0;
  glBegin(GL_QUAD_STRIP);
  for(float i = 0; i < nbSteps; ++i) {
    float ratio = i / nbSteps;
    float angle = 21.0 * ratio;
    float c = cos(angle);
    float s = sin(angle);
    float r1 = 1.0 - 0.8 * ratio;
    float r2 = 0.8 - 0.8 * ratio;
    float alt = ratio - 0.5;
    const float nor = .5;
    const float up = sqrt(1.0 - nor * nor);
    glColor3f(1.0 - ratio, 0.2f, ratio);
    glNormal3f(nor * c, up, nor * s);
    glVertex3f(r1 * c, alt, r1 * s);
    glVertex3f(r2 * c, alt + 0.05, r2 * s);
  }
  glEnd();
}

void Viewer::init()
{
// Swap the CAMERA and FRAME state keys (NoButton and Control)
// Save CAMERA binding first. See setHandlerKeyboardModifiers() documentation.
#if QT_VERSION < 0x040000
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::AltButton);
  setHandlerKeyboardModifiers(QGLViewer::FRAME, Qt::NoButton);
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::ControlButton);
#else
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::AltModifier);
  setHandlerKeyboardModifiers(QGLViewer::FRAME, Qt::NoModifier);
  setHandlerKeyboardModifiers(QGLViewer::CAMERA, Qt::ControlModifier);
#endif

#ifdef GL_RESCALE_NORMAL // OpenGL 1.2 Only...
  glEnable(GL_RESCALE_NORMAL);
#endif

  // Add a manipulated frame to the viewer.
  // If you are not "using namespace qglqglviewer", you need
  // to specify: new qglviewer::ManipulatedFrame().
  setManipulatedFrame(new ManipulatedFrame());

  help();
  restoreStateFromFile();

  // Make world axis visible
  setAxisIsDrawn();
}

void Viewer::draw()
{
  // Here we are in the world coordinate system.
  // Draw your scene here.

  // Save the current model view matrix (not needed here in fact)
  glPushMatrix();

  // Multiply matrix to get in the frame coordinate system.
  glMultMatrixd(manipulatedFrame()->matrix());

  // Scale down the drawings
  glScalef(0.3f, 0.3f, 0.3f);

  // Draw an axis using the QGLViewer static function
  drawAxis();

  // Draws a frame-related spiral.
  drawSpiral();

  // Restore the original (world) coordinate system
  glPopMatrix();
}

QString Viewer::helpString() const
{
  QString text("<h2>M a n i p u l a t e d F r a m e</h2>");
  text += "A <i>ManipulatedFrame</i> converts mouse gestures into <i>Frame</i> displacements. ";
  text += "In this example, such an object defines the position of the spiral that can hence be manipulated.<br><br>";
  text += "Adding two lines of code will then allow you to move the objects of ";
  text += "your scene using the mouse. The button bindings of the <i>ManipulatedFrame</i> ";
  text += "are the same than for the camera. Spinning is possible.<br><br>";
  text += "Default key bindings have been changed in this example : press <b>Control</b> ";
  text += "while moving the mouse to move the camera instead of the ManipulatedFrame.";
  return text;
}
