#ifndef MATH_UMATRIX_H
#define MATH_UMATRIX_H

/*

  GLT OpenGL C++ Toolkit (LGPL)
  Copyright (C) 2000-2002 Nigel Stewart  

  Email: nigels@nigels.com   
  WWW:   http://www.nigels.com/glt/

  This library 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 2.1 of the License, or (at your option) any later version.

  This 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

/*! \file 
    \brief   4 GltUnMatrix
	\ingroup Math
*/

#include <iosfwd>

#include "glt_real.h"
#include "glt_vector3.h"

class GltMatrix;

////////////////////////// GltUnMatrix /////////////////////////////////

/*! \enum    UnMatrixField 
    \brief   4x4 GltUnMatrix Field
	\ingroup Math
	\author  Nigel Stewart, RMIT (nigels@nigels.com)
	\author  Spencer W. Thomas, University of Michigan
	\todo    Replace enums with descriptive class interface.
*/

typedef enum
{
 	U_SCALEX = 0,
 	U_SCALEY,
 	U_SCALEZ,
 	U_SHEARXY,
 	U_SHEARXZ,
 	U_SHEARYZ,
 	U_ROTATEX,
 	U_ROTATEY,
 	U_ROTATEZ,
 	U_TRANSX,
 	U_TRANSY,
 	U_TRANSZ,
 	U_PERSPX,
 	U_PERSPY,
 	U_PERSPZ,
 	U_PERSPW,
	U_MAX
} UnMatrixField;

/*! \class   GltUnMatrix 
    \brief   4x4 GltUnMatrix
	\ingroup Math
	\author  Nigel Stewart, RMIT (nigels@nigels.com)
	\author  Spencer W. Thomas, University of Michigan
	
	Graphics Gems II - Decomposing a matrix into simple transformations. Pg. 320

	The unmatrix subroutine fills in a vector of floating point
	values.  These symbols make it easier to get the data back out.
*/

class GltUnMatrix
{
	friend class GltMatrix;

	friend std::ostream &operator<<(std::ostream &os,const UnMatrixField &field);
	friend std::ostream &operator<<(std::ostream &os,const GltUnMatrix &unMatrix);

	friend std::istream &operator>>(std::istream &is,UnMatrixField &field);
	friend std::istream &operator>>(std::istream &is,GltUnMatrix &unMatrix);

	friend GltUnMatrix operator-(const GltUnMatrix &b,const GltUnMatrix &a);
	friend GltUnMatrix operator*(const GltUnMatrix &a,const double scaleFactor);
	friend GltUnMatrix operator+(const GltUnMatrix &a,const GltUnMatrix &b);

public:
	/// Constructor
	GltUnMatrix();
	/// Copy Constructor
	GltUnMatrix(const GltUnMatrix &);

	/// Construct from 4x4 matrix
	GltUnMatrix(const GltMatrix &matrix);

	/// Destructor
	~GltUnMatrix();

	/// Is the scale uniform?
	bool uniformScale (const double tol = 1.0e-4) const;
	/// Is there no rotation transformation?
	bool noRotation   (const double tol = 1.0e-4) const;
	/// Is there no shear transformation?
	bool noShear      (const double tol = 1.0e-4) const;
	/// Is there no perspective transformation?
	bool noPerspective(const double tol = 1.0e-4) const;

	/// Access GltUnMatrix fields
	double &operator[](const UnMatrixField field) { return _tran[field]; };

private:
	double _tran[16];
};

#endif