/* BurrTools
 *
 * BurrTools is the legal property of its developers, whose
 * names are listed in the COPYRIGHT file, which is included
 * within the source distribution.
 *
 * This program 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.

 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
#ifndef __ARCBALL_H__
#define __ARCBALL_H__

/* base class for all classes that allow rotating objects by
 * dragging a point on screen
 */
class rotater_c {
  public:
    /**
     * change the size of the area where the mouse can move to
     */
    virtual void setBounds(float NewWidth, float NewHeight) = 0;

    /**
     * the mouse starts to drag, give the position of the cursor
     */
    virtual void click(float x, float y) = 0;

    /**
     * end the mouse dragging at the given position
     */
    virtual void clack(float x, float y) = 0;

    /**
     * update the position of the mouse cursor, while dragging is active
     */
    virtual void drag(float x, float y) = 0;

    /**
     * adds the current arcball transformation to the OpenGL transformation matrix
     */
    virtual void addTransform(void) const = 0;
};

/**
 * This class provides an implementation of an arcball. The mathematics of this is explained within the code
 * Arcball is an algorithm that allows you to meaningful rotate objects by dragging them.
 * The problem normally is that you must rotate the objects differently depending on their
 * current rotation, when you want to drag them. This is handled in here.
 *
 * The class needs to know the size of the area where you can drag, so that it can make sense
 * out of the given mouse positions. The rest of the handling is basic
 */
class arcBall_c : public rotater_c
{

  private:

    void mapToSphere(float x, float y, float NewVec[3]) const;
    void getDrag(float NewRot[4]) const;

  public:

    /**
     * create arcball class with an initial size for the drag area
     */
    arcBall_c(float NewWidth, float NewHeight);

    void setBounds(float NewWidth, float NewHeight);
    void click(float x, float y);
    void clack(float x, float y);
    void drag(float x, float y);
    void addTransform(void) const;

  private:

    float AdjustWidth;       //Mouse bounds width
    float AdjustHeight;      //Mouse bounds height

    float StVec[3];          //Saved click vector
    float EnVec[3];          //Saved drag vector

    float LastRot[9];

    bool mouseDown;
};

// another way to rotate an object, the code for this method has been
// taken from the GL viewer class of the FOX-Toolkit library and
// adapted for usage in here...
class method2_c : public rotater_c {

    float AdjustWidth;       //Mouse bounds width
    float AdjustHeight;      //Mouse bounds height

    float rotation[4];

    float last_x, last_y;

    bool mouseDown;

  public:

    method2_c(float NewWidth, float NewHeight);

    void setBounds(float NewWidth, float NewHeight);
    void click(float x, float y);
    void clack(float x, float y);
    void drag(float x, float y);
    void addTransform(void) const;

  private:

    void spherePoint(float px, float py, float v[3]);

};

#endif