demos/opengl/trackball.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, 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.
//
// Eigen 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 Lesser General Public License or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.

#ifndef EIGEN_TRACKBALL_H
#define EIGEN_TRACKBALL_H

#include <Eigen/Geometry>

class Camera;

class Trackball
{
  public:

    enum Mode {Around, Local};

    Trackball() : mpCamera(0) {}

    void start(Mode m = Around) { mMode = m; mLastPointOk = false; }

    void setCamera(Camera* pCam) { mpCamera = pCam; }

    void track(const Eigen::Vector2i& newPoint2D);

  protected:

    bool mapToSphere( const Eigen::Vector2i& p2, Eigen::Vector3f& v3);

    Camera* mpCamera;
    Eigen::Vector3f mLastPoint3D;
    Mode mMode;
    bool mLastPointOk;

};

#endif // EIGEN_TRACKBALL_H