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matrix3x3.cc

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/*
  svas_server -- virtual World Server of Svas
  Copyright (c) 2001, 2002 David Moreno Montero
 
 
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU 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
  General Public License for more details.
 
  You should have received a copy of the GNU 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.  

*/

/// Adapted from 
///
/// Physics for Game Developers
/// David M. Bourg
/// O'Reilly
/// ISBN 0-596-00006-5


#include "matrix3x3.h"
#include "log.h"
#include <stdio.h>

inline Matrix3x3::Matrix3x3(void){
  e11=1; e12=0; e13=0;
  e21=0; e22=1; e23=0;
  e31=0; e32=0; e33=1;
}

inline Matrix3x3::Matrix3x3(double aa, double ab, double ac,
             double ba, double bb, double bc,
             double ca, double cb, double cc){
  e11=aa;  e12=ab;  e13=ac;
  e21=ba;  e22=bb;  e23=bc;
  e31=ca;  e32=cb;  e33=cc;
}

inline string Matrix3x3::toString(){
  char str[256];
  sprintf(str, "((%g,%g,%g)(%g,%g,%g)(%g,%g,%g))",
      e11,e12,e13,
      e21,e22,e23,
      e31,e32,e33);
  return string(str);
}

inline double Matrix3x3::Determinant(){
  return 
    e11*e22*e33 -
    e11*e32*e23 +
    e21*e32*e13 -
    e21*e12*e33 +
    e31*e12*e23 -
    e31*e22*e13;
}

inline Matrix3x3 Matrix3x3::Transpose(){
  return Matrix3x3(e11,e21,e31,e12,e22,e32,e13,e23,e33);
}

inline Matrix3x3 Matrix3x3::Inverse(){
  double d=Determinant();
  
  d=(d==0) ? 1 : d;
  
  return Matrix3x3( (e22*e33-e23*e32)/d,
           -(e12*e33-e13*e32)/d,
           -(e12*e33-e13*e22)/d,
           -(e21*e33-e23*e31)/d,
            (e11*e33-e13*e31)/d,
           -(e11*e23-e13*e21)/d,
            (e21*e32-e22*e31)/d,
           -(e11*e32-e12*e31)/d,
            (e11*e22-e12*e21)/d);
}

inline Matrix3x3 &Matrix3x3::operator+=(const Matrix3x3 &m){
  e11+=m.e11;  e12+=m.e12;  e13+=m.e13;
  e21+=m.e21;  e22+=m.e22;  e23+=m.e23;
  e31+=m.e31;  e32+=m.e32;  e33+=m.e33;
  return *this;
}

inline Matrix3x3 &Matrix3x3::operator-=(const Matrix3x3 &m){
  e11-=m.e11;  e12-=m.e12;  e13-=m.e13;
  e21-=m.e21;  e22-=m.e22;  e23-=m.e23;
  e31-=m.e31;  e32-=m.e32;  e33-=m.e33;
  return *this;
}

inline Matrix3x3 operator*(const Matrix3x3 &A, const Matrix3x3 &B){
  log <<"This method need check!"<<endl; //FIXME
  return Matrix3x3(A.e11*B.e11 + A.e12*B.e21 + A.e13*B.e31,
           A.e21*B.e11 + A.e22*B.e21 + A.e23*B.e31,
           A.e31*B.e11 + A.e32*B.e21 + A.e33*B.e31,

           A.e11*B.e12 + A.e12*B.e22 + A.e13*B.e32,
           A.e21*B.e12 + A.e22*B.e22 + A.e23*B.e32,
           A.e31*B.e12 + A.e32*B.e22 + A.e33*B.e32,

           A.e11*B.e13 + A.e12*B.e23 + A.e13*B.e33,
           A.e21*B.e13 + A.e22*B.e23 + A.e23*B.e33,
           A.e31*B.e13 + A.e32*B.e23 + A.e33*B.e33);

  /*
  int i,j,k;
  double t;
  Matrix3x3 ret;
  for (i=0;i<3;i++)
    for (j=0;j<3;j++){
      t=0;
      for (k=0;k<3;k++)
    t+=A.mat[(i*3)+k]*B.mat[(k*3)+j];
      ret.mat[(i*3)+j]=t;
    }
  return ret;
  */
}

inline Vector3d operator*(const Matrix3x3 &M, const Vector3d &v){
  return Vector3d ( M.e11*v.x + M.e12*v.y + M.e13*v.z,
            M.e21*v.x + M.e22*v.y + M.e23*v.z,
            M.e31*v.x + M.e32*v.y + M.e33*v.z);
}

inline Vector3d operator*(const Vector3d &v, const Matrix3x3 &M){
  return Vector3d ( M.e11*v.x + M.e21*v.y + M.e31*v.z,
            M.e12*v.x + M.e22*v.y + M.e32*v.z,
            M.e13*v.x + M.e23*v.y + M.e33*v.z);
}

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