/**
 * =========================================================================
 * File        : Quaternion.h
 * Project     : 0 A.D.
 * Description : 
 * =========================================================================
 */

#ifndef INCLUDED_QUATERNION
#define INCLUDED_QUATERNION

#include "Matrix3D.h"
#include "Vector3D.h"

class CQuaternion
{
public:
    CVector3D   m_V;
    float       m_W;

public:
    CQuaternion();
    CQuaternion(float x, float y, float z, float w);
    
    CQuaternion operator + (const CQuaternion &quat) const;
    CQuaternion &operator += (const CQuaternion &quat);

    CQuaternion operator -(const CQuaternion &quat) const;
    CQuaternion &operator -= (const CQuaternion &quat);

    CQuaternion operator * (const CQuaternion &quat) const;
    CQuaternion &operator *= (const CQuaternion &quat);

    CQuaternion operator * (float factor) const;

    float Dot(const CQuaternion& quat) const;
    
    void FromEulerAngles (float x, float y, float z);
    CVector3D ToEulerAngles();
    
    // Convert the quaternion to matrix
    CMatrix3D ToMatrix() const;
    void ToMatrix(CMatrix3D& result) const;

    // Sphere interpolation
    void Slerp(const CQuaternion& from, const CQuaternion& to, float ratio);

    // Normalised linear interpolation
    void Nlerp(const CQuaternion& from, const CQuaternion& to, float ratio);

    // Create a quaternion from axis/angle representation of a rotation
    void FromAxisAngle(const CVector3D& axis, float angle);

    // Convert the quaternion to axis/angle representation of a rotation
    void ToAxisAngle(CVector3D& axis, float& angle);

    // Normalize this quaternion
    void Normalize();

    // Rotate a vector by this quaternion. Assumes the quaternion is normalised.
    CVector3D Rotate(const CVector3D& vec) const;

    // Calculate q^-1. Assumes the quaternion is normalised.
    CQuaternion GetInverse() const;
};

#endif