started a small OpenGL demo making use of Eigen's geometry features

1 files changed, 55 insertions, 0 deletions

diff --git a/demos/opengl/trackball.h b/demos/opengl/trackball.h
new file mode 100644
index 000000000..29413becd
--- /dev/null
+++ b/demos/opengl/trackball.h
@@ -0,0 +1,55 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008 Gael Guennebaud <g.gael@free.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:
+
+    Trackball() : mpCamera(0) {}
+
+    void reset() { 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::Vector2i mLastPoint2D;
+    Eigen::Vector3f mLastPoint3D;
+    bool mLastPointOk;
+
+};
+
+#endif // EIGEN_TRACKBALL_H