/*------------------------------------------------------------------------

 *

 * OpenVG 1.1 Reference Implementation

 * -----------------------------------

 *

 * Copyright (c) 2007 The Khronos Group Inc.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and /or associated documentation files

 * (the "Materials "), to deal in the Materials without restriction,

 * including without limitation the rights to use, copy, modify, merge,

 * publish, distribute, sublicense, and/or sell copies of the Materials,

 * and to permit persons to whom the Materials are furnished to do so,

 * subject to the following conditions: 

 *

 * The above copyright notice and this permission notice shall be included 

 * in all copies or substantial portions of the Materials. 

 *

 * THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE MATERIALS OR

 * THE USE OR OTHER DEALINGS IN THE MATERIALS.

 *

 *//**

 * \file

 * \brief	Implementation of non-inline matrix functions.

 * \note	

 *//*-------------------------------------------------------------------*/

#include "riDefs.h"

#include "riMath.h"

namespace OpenVGRI

{

/*-------------------------------------------------------------------*//*!

* \brief	Inverts a 3x3 matrix. Returns false if the matrix is singular.

* \param	

* \return	

* \note		

*//*-------------------------------------------------------------------*/

bool Matrix3x3::invert()

{

	bool affine = isAffine();

	RIfloat det00 = matrix[1][1]*matrix[2][2] - matrix[2][1]*matrix[1][2];

	RIfloat det01 = matrix[2][0]*matrix[1][2] - matrix[1][0]*matrix[2][2];

	RIfloat det02 = matrix[1][0]*matrix[2][1] - matrix[2][0]*matrix[1][1];

	RIfloat d = matrix[0][0]*det00 + matrix[0][1]*det01 + matrix[0][2]*det02;

	if( d == 0.0f ) return false;	//singular, leave the matrix unmodified and return false

	d = 1.0f / d;

	Matrix3x3 t;

	t[0][0] = d * det00;

	t[1][0] = d * det01;

	t[2][0] = d * det02;

	t[0][1] = d * (matrix[2][1]*matrix[0][2] - matrix[0][1]*matrix[2][2]);

	t[1][1] = d * (matrix[0][0]*matrix[2][2] - matrix[2][0]*matrix[0][2]);

	t[2][1] = d * (matrix[2][0]*matrix[0][1] - matrix[0][0]*matrix[2][1]);

	t[0][2] = d * (matrix[0][1]*matrix[1][2] - matrix[1][1]*matrix[0][2]);

	t[1][2] = d * (matrix[1][0]*matrix[0][2] - matrix[0][0]*matrix[1][2]);

	t[2][2] = d * (matrix[0][0]*matrix[1][1] - matrix[1][0]*matrix[0][1]);

	if(affine)

		t[2].set(0,0,1);	//affine matrix stays affine

	*this = t;

	return true;

}

//==============================================================================================

}	//namespace OpenVGRI