/***************************************************************************
 * Quaternion class written by BlackAxe / Kolor aka Laurent Schmalen in 1997
 * this class is freeware. you are fully allowed to use this class in non-
 * commercial products. Use in commercial environment is strictly prohibited
 * if you use this, i'll be happy if you greet/credit me and my group
 *
 * Official Version 0.9
 *
 * Laurent aka Blackaxe/KoLoR
 */


#ifndef BA_QUATERNION_H__ 
#define BA_QUATERNION_H__ 
 
#include <iostream.h> 
 
#ifndef PI 
#define PI 3.14159264 
#endif 
 
class Quaternion 
{ 
  private: 
    float W, X, Y, Z;      // components of a quaternion 
 
  public: 
    // default constructor 
    Quaternion(); 
    Quaternion(const Quaternion& source); 
    Quaternion(const float, const float = 0.0, const float = 0.0, const float = 0.0); 
   
    // print a quaternion using streams 
    void PrintOn(ostream& = cout) const; 
 
    // quaternion multiplication 
    friend Quaternion operator * (const Quaternion&, const Quaternion&); 
    const Quaternion& operator *= (const Quaternion&); 
 
    // konjugiertes Quaternion 
    const Quaternion& operator ~ (); 
 
    // this function inverts the quaternion 
    const Quaternion& operator - (); 
 
    // this normalizes a quaternion  
    const Quaternion& Normalize(); 
    const Quaternion& FromAxis(const float, float, float, float); 
    void ToMatrix(float matrix[3][3]) const; 
    void ToMatrix16(float matrix[16]) const; 
 
    void Slerp(const Quaternion&, const Quaternion&, const float); 
 
    // some additional Quaternion functions 
    // getting the exponent of a quaternion 
    const Quaternion& exp(); 
    const Quaternion& log(); 
}; 
 
inline ostream& operator << (ostream &strm, const Quaternion &q) 
{ 
  q.PrintOn(strm); 
  return strm; 
} 
 
#endif