/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright © 2000-2002 The OGRE Team
Also see acknowledgements in Readme.html

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

This program 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 program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
-----------------------------------------------------------------------------
*/
#include "OgreStableHeaders.h"
#include "OgreMatrix4.h"

#include "OgreVector3.h"
#include "OgreMatrix3.h"

namespace Ogre
{

    const Matrix4 Matrix4::ZERO(
        0, 0, 0, 0,
        0, 0, 0, 0,
        0, 0, 0, 0,
        0, 0, 0, 0 );

    const Matrix4 Matrix4::IDENTITY(
        1, 0, 0, 0,
        0, 1, 0, 0,
        0, 0, 1, 0,
        0, 0, 0, 1 );

    const Matrix4 Matrix4::CLIPSPACE2DTOIMAGESPACE(
        0.5,    0,  0, 0.5, 
          0, -0.5,  0, 0.5, 
          0,    0,  1,   0,
          0,    0,  0,   1);

    inline Real
        MINOR(const Matrix4& m, const size_t r0, const size_t r1, const size_t r2, 
								const size_t c0, const size_t c1, const size_t c2)
    {
        return m[r0][c0] * (m[r1][c1] * m[r2][c2] - m[r2][c1] * m[r1][c2]) -
            m[r0][c1] * (m[r1][c0] * m[r2][c2] - m[r2][c0] * m[r1][c2]) +
            m[r0][c2] * (m[r1][c0] * m[r2][c1] - m[r2][c0] * m[r1][c1]);
    }


    Matrix4 Matrix4::adjoint() const
    {
        return Matrix4( MINOR(*this, 1, 2, 3, 1, 2, 3),
            -MINOR(*this, 0, 2, 3, 1, 2, 3),
            MINOR(*this, 0, 1, 3, 1, 2, 3),
            -MINOR(*this, 0, 1, 2, 1, 2, 3),

            -MINOR(*this, 1, 2, 3, 0, 2, 3),
            MINOR(*this, 0, 2, 3, 0, 2, 3),
            -MINOR(*this, 0, 1, 3, 0, 2, 3),
            MINOR(*this, 0, 1, 2, 0, 2, 3),

            MINOR(*this, 1, 2, 3, 0, 1, 3),
            -MINOR(*this, 0, 2, 3, 0, 1, 3),
            MINOR(*this, 0, 1, 3, 0, 1, 3),
            -MINOR(*this, 0, 1, 2, 0, 1, 3),

            -MINOR(*this, 1, 2, 3, 0, 1, 2),
            MINOR(*this, 0, 2, 3, 0, 1, 2),
            -MINOR(*this, 0, 1, 3, 0, 1, 2),
            MINOR(*this, 0, 1, 2, 0, 1, 2));
    }


    Real Matrix4::determinant() const
    {
        return m[0][0] * MINOR(*this, 1, 2, 3, 1, 2, 3) -
            m[0][1] * MINOR(*this, 1, 2, 3, 0, 2, 3) +
            m[0][2] * MINOR(*this, 1, 2, 3, 0, 1, 3) -
            m[0][3] * MINOR(*this, 1, 2, 3, 0, 1, 2);
    }

    Matrix4 Matrix4::inverse() const
    {
        return adjoint() * (1.0f / determinant());
    }

}
