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>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// SPDX-License-Identifier: MPL-2.0

#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