/usr/include/crystalspace-2.0/csgeom/matrix2.h is in libcrystalspace-dev 2.0+dfsg-1build1.
This file is owned by root:root, with mode 0o644.
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Copyright (C) 2000 by Jorrit Tyberghein
Largely rewritten by Ivan Avramovic <ivan@avramovic.com>
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 "csgeom/vector2.h"
/**\file
* 2x2 matrix.
*/
/**
* \addtogroup geom_utils
* @{ */
/**
* A 2x2 matrix.
*/
class csMatrix2
{
public:
float m11, m12;
float m21, m22;
public:
/// Construct a matrix, initialized to be the identity.
csMatrix2 ()
: m11 (1), m12 (0), m21 (0), m22 (1)
{}
/// Construct a matrix and initialize it.
csMatrix2 (float m11, float m12,
float m21, float m22)
: m11 (m11), m12 (m12), m21 (m21), m22 (m22)
{}
/// Get the first row of this matrix as a vector.
inline csVector2 Row1() const
{ return csVector2 (m11,m12); }
/// Get the second row of this matrix as a vector.
inline csVector2 Row2() const
{ return csVector2 (m21,m22); }
/// Get the first column of this matrix as a vector.
inline csVector2 Col1() const
{ return csVector2 (m11,m21); }
/// Get the second column of this matrix as a vector.
inline csVector2 Col2() const
{ return csVector2 (m12,m22); }
/// Set matrix values.
inline void Set (float m11, float m12,
float m21, float m22)
{
csMatrix2::m11 = m11; csMatrix2::m12 = m12;
csMatrix2::m21 = m21; csMatrix2::m22 = m22;
}
/// Add another matrix to this matrix.
inline csMatrix2& operator+= (const csMatrix2& m)
{
m11 += m.m11; m12 += m.m12;
m21 += m.m21; m22 += m.m22;
return *this;
}
/// Subtract another matrix from this matrix.
inline csMatrix2& operator-= (const csMatrix2& m)
{
m11 -= m.m11; m12 -= m.m12;
m21 -= m.m21; m22 -= m.m22;
return *this;
}
/// Multiply another matrix with this matrix.
inline csMatrix2& operator*= (const csMatrix2& m)
{
csMatrix2 r (*this);
m11 = r.m11 * m.m11 + r.m12 * m.m21;
m12 = r.m11 * m.m12 + r.m12 * m.m22;
m21 = r.m21 * m.m11 + r.m22 * m.m21;
m22 = r.m21 * m.m12 + r.m22 * m.m22;
return *this;
}
/// Multiply this matrix with a scalar.
inline csMatrix2& operator*= (float s)
{
m11 *= s; m12 *= s;
m21 *= s; m22 *= s;
return *this;
}
/// Divide this matrix by a scalar.
inline csMatrix2& operator/= (float s)
{
s=1.0f/s;
m11 *= s; m12 *= s;
m21 *= s; m22 *= s;
return *this;
}
/// Unary + operator.
inline csMatrix2 operator+ () const
{ return *this; }
/// Unary - operator.
inline csMatrix2 operator- () const
{
return csMatrix2 (-m11,-m12, -m21,-m22);
}
/// Transpose this matrix.
inline void Transpose ()
{
float swap = m12;
m12 = m21;
m21 = swap;
}
/// Return the transpose of this matrix.
inline csMatrix2 GetTranspose () const
{
return csMatrix2 (m11, m21, m12, m22);
}
/// Return the inverse of this matrix.
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);
}
/// Invert this matrix.
inline void Invert ()
{ *this = GetInverse (); }
/// Compute the determinant of this matrix.
inline float Determinant () const
{ return m11 * m22 - m12 * m21; }
/// Set this matrix to the identity matrix.
inline void Identity ()
{
m11 = m22 = 1;
m12 = m21 = 0;
}
/// Add two matricies.
inline friend csMatrix2 operator+ (const csMatrix2& m1, const csMatrix2& m2)
{
return csMatrix2 (
m1.m11 + m2.m11, m1.m12 + m2.m12,
m1.m21 + m2.m21, m1.m22 + m2.m22);
}
/// Subtract two matricies.
inline friend csMatrix2 operator- (const csMatrix2& m1, const csMatrix2& m2)
{
return csMatrix2 (
m1.m11 - m2.m11, m1.m12 - m2.m12,
m1.m21 - m2.m21, m1.m22 - m2.m22);
}
/// Multiply two matricies.
inline friend csMatrix2 operator* (const csMatrix2& m1, const csMatrix2& m2)
{
return csMatrix2 (
m1.m11 * m2.m11 + m1.m12 * m2.m21,
m1.m11 * m2.m12 + m1.m12 * m2.m22,
m1.m21 * m2.m11 + m1.m22 * m2.m21,
m1.m21 * m2.m12 + m1.m22 * m2.m22);
}
/// Multiply a vector by a matrix (transform it).
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); }
/// Multiply a matrix and a scalar.
inline friend csMatrix2 operator* (const csMatrix2& m, float f)
{ return csMatrix2 (m.m11 * f, m.m12 * f, m.m21 * f, m.m22 * f); }
/// Multiply a matrix and a scalar.
inline friend csMatrix2 operator* (float f, const csMatrix2& m)
{ return csMatrix2 (m.m11 * f, m.m12 * f, m.m21 * f, m.m22 * f); }
/// Divide a matrix by a scalar.
inline friend csMatrix2 operator/ (const csMatrix2& m, float f)
{
float inv_f = 1 / f;
return csMatrix2 (
m.m11 * inv_f, m.m12 * inv_f,
m.m21 * inv_f, m.m22 * inv_f);
}
};
/** @} */
#endif // __CS_MATRIX2_H__
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