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csgeom/matrix2.h

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/*
    Copyright (C) 2000 by Jorrit Tyberghein
    Largely rewritten by Ivan Avramovic <[email protected]>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifndef __CS_MATRIX2_H__
#define __CS_MATRIX2_H__

#include "csextern.h"

#include "csgeom/vector2.h"

class CS_CRYSTALSPACE_EXPORT csMatrix2
{
public:
  float m11, m12;
  float m21, m22;

public:
  csMatrix2 ();

  csMatrix2 (float m11, float m12,
             float m21, float m22);

  inline csVector2 Row1() const { return csVector2 (m11,m12); }

  inline csVector2 Row2() const { return csVector2 (m21,m22); }

  inline csVector2 Col1() const { return csVector2 (m11,m21); }

  inline csVector2 Col2() const { return csVector2 (m12,m22); }

  inline void Set (float m11, float m12,
                   float m21, float m22)
  {
    csMatrix2::m11 = m11; csMatrix2::m12 = m12;
    csMatrix2::m21 = m21; csMatrix2::m22 = m22;
  }

  csMatrix2& operator+= (const csMatrix2& m);

  csMatrix2& operator-= (const csMatrix2& m);

  csMatrix2& operator*= (const csMatrix2& m);

  csMatrix2& operator*= (float s);

  csMatrix2& operator/= (float s);

  inline csMatrix2 operator+ () const { return *this; }
  inline csMatrix2 operator- () const
  {
    return csMatrix2(-m11,-m12, -m21,-m22);
  }

  void Transpose ();

  csMatrix2 GetTranspose () const;

  inline csMatrix2 GetInverse () const
  {
    float inv_det = 1 / (m11 * m22 - m12 * m21);
    return csMatrix2 (m22 * inv_det, -m12 * inv_det,
                      -m21 * inv_det, m11 * inv_det);
  }

  void Invert () { *this = GetInverse (); }

  float Determinant () const;

  void Identity ();

  friend csMatrix2 operator+ (const csMatrix2& m1, const csMatrix2& m2);
  friend csMatrix2 operator- (const csMatrix2& m1, const csMatrix2& m2);
  friend csMatrix2 operator* (const csMatrix2& m1, const csMatrix2& m2);

  inline friend csVector2 operator* (const csMatrix2& m, const csVector2& v)
  {
    return csVector2 (m.m11*v.x + m.m12*v.y, m.m21*v.x + m.m22*v.y);
  }

  friend csMatrix2 operator* (const csMatrix2& m, float f);
  friend csMatrix2 operator* (float f, const csMatrix2& m);
  friend csMatrix2 operator/ (const csMatrix2& m, float f);
};

#endif // __CS_MATRIX2_H__

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