matrix2.h Source File

00001 /*
00002     Copyright (C) 2000 by Jorrit Tyberghein
00003     Largely rewritten by Ivan Avramovic <ivan@avramovic.com>
00004 
00005     This library is free software; you can redistribute it and/or
00006     modify it under the terms of the GNU Library General Public
00007     License as published by the Free Software Foundation; either
00008     version 2 of the License, or (at your option) any later version.
00009 
00010     This library is distributed in the hope that it will be useful,
00011     but WITHOUT ANY WARRANTY; without even the implied warranty of
00012     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013     Library General Public License for more details.
00014 
00015     You should have received a copy of the GNU Library General Public
00016     License along with this library; if not, write to the Free
00017     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00018 */
00019 
00020 #ifndef __CS_MATRIX2_H__
00021 #define __CS_MATRIX2_H__
00022 
00023 #include "csgeom/vector2.h"
00024 
00028 class csMatrix2
00029 {
00030 public:
00031   float m11, m12;
00032   float m21, m22;
00033 
00034 public:
00036   csMatrix2 ();
00037 
00039   csMatrix2 (float m11, float m12,
00040              float m21, float m22);
00041 
00043   inline csVector2 Row1() const { return csVector2 (m11,m12); }
00044 
00046   inline csVector2 Row2() const { return csVector2 (m21,m22); }
00047 
00049   inline csVector2 Col1() const { return csVector2 (m11,m21); }
00050 
00052   inline csVector2 Col2() const { return csVector2 (m12,m22); }
00053 
00055   inline void Set (float m11, float m12,
00056                    float m21, float m22)
00057   {
00058     csMatrix2::m11 = m11; csMatrix2::m12 = m12;
00059     csMatrix2::m21 = m21; csMatrix2::m22 = m22;
00060   }
00061 
00063   csMatrix2& operator+= (const csMatrix2& m);
00064 
00066   csMatrix2& operator-= (const csMatrix2& m);
00067 
00069   csMatrix2& operator*= (const csMatrix2& m);
00070 
00072   csMatrix2& operator*= (float s);
00073 
00075   csMatrix2& operator/= (float s);
00076 
00078   inline csMatrix2 operator+ () const { return *this; }
00080   inline csMatrix2 operator- () const
00081   {
00082     return csMatrix2(-m11,-m12, -m21,-m22);
00083   }
00084 
00086   void Transpose ();
00087 
00089   csMatrix2 GetTranspose () const;
00090 
00092   inline csMatrix2 GetInverse () const
00093   {
00094     float inv_det = 1 / (m11 * m22 - m12 * m21);
00095     return csMatrix2 (m22 * inv_det, -m12 * inv_det, -m21 * inv_det, m11 * inv_det);
00096   }
00097 
00099   void Invert () { *this = GetInverse (); }
00100 
00102   float Determinant () const;
00103 
00105   void Identity ();
00106 
00108   friend csMatrix2 operator+ (const csMatrix2& m1, const csMatrix2& m2);
00110   friend csMatrix2 operator- (const csMatrix2& m1, const csMatrix2& m2);
00112   friend csMatrix2 operator* (const csMatrix2& m1, const csMatrix2& m2);
00113 
00115   inline friend csVector2 operator* (const csMatrix2& m, const csVector2& v)
00116   {
00117     return csVector2 (m.m11*v.x + m.m12*v.y, m.m21*v.x + m.m22*v.y);
00118   }
00119 
00121   friend csMatrix2 operator* (const csMatrix2& m, float f);
00123   friend csMatrix2 operator* (float f, const csMatrix2& m);
00125   friend csMatrix2 operator/ (const csMatrix2& m, float f);
00126 };
00127 
00128 #endif // __CS_MATRIX2_H__
00129