+/*
+This file is part of the n3dmath2 library.
+
+Copyright (c) 2003 - 2005 John Tsiombikas <nuclear@siggraph.org>
+
+The n3dmath2 library 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.
+
+The n3dmath2 library 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 the n3dmath2 library; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+/* quaterinion math
+ *
+ * Author: John Tsiombikas 2003
+ * Modified: John Tsiombikas 2004, 2005
+ */
+
+#ifndef _N3DMATH2_QUA_HPP_
+#define _N3DMATH2_QUA_HPP_
+
+#include <iostream>
+#include "n3dmath2_types.hpp"
+
+class Quaternion {
+public:
+ scalar_t s;
+ Vector3 v;
+
+ Quaternion();
+ Quaternion(scalar_t s, const Vector3 &v);
+ Quaternion(scalar_t s, scalar_t x, scalar_t y, scalar_t z);
+ Quaternion(const Vector3 &axis, scalar_t angle);
+
+ Quaternion operator +(const Quaternion &quat) const;
+ Quaternion operator -(const Quaternion &quat) const;
+ Quaternion operator -() const;
+ Quaternion operator *(const Quaternion &quat) const;
+
+ void operator +=(const Quaternion &quat);
+ void operator -=(const Quaternion &quat);
+ void operator *=(const Quaternion &quat);
+
+ void reset_identity();
+
+ Quaternion conjugate() const;
+
+ scalar_t length() const;
+ scalar_t length_sq() const;
+
+ void normalize();
+ Quaternion normalized() const;
+
+ Quaternion inverse() const;
+
+ void set_rotation(const Vector3 &axis, scalar_t angle);
+ void rotate(const Vector3 &axis, scalar_t angle);
+ /* note: this is a totally different operation from the above
+ * this treats the quaternion as signifying direction and rotates
+ * it by a rotation quaternion by rot * q * rot'
+ */
+ void rotate(const Quaternion &q);
+
+ Matrix3x3 get_rotation_matrix() const;
+
+ friend Quaternion slerp(const Quaternion &q1, const Quaternion &q2, scalar_t t);
+
+ friend std::ostream &operator <<(std::ostream &out, const Quaternion &q);
+};
+
+
+#endif // _N3DMATH2_QUA_HPP_