// MATRIX.cpp: implementation of the MATRIX class.////////////////////////////////////////////////////////////////////////#include "VECTOR.H"#include "MATRIX.h"// This class MATRIX comes from an article about rigid body// animation published on www.gamasutra.com so it may// follow its own license. Please check gamasutra at// http://www.gamasutra.com/features/19990702/data_structures_01.htm// or just write your own to replace it.//////////////////////////////////////////////////////////////////////// Construction/Destruction//////////////////////////////////////////////////////////////////////MATRIX::MATRIX(){	//identity matrix	C[0].x = 1;	C[1].y = 1;	C[2].z = 1;}MATRIX::MATRIX( const VECTOR& c0, const VECTOR& c1, const VECTOR& c2 ){	C[0] = c0;	C[1] = c1;	C[2] = c2;}VECTOR& MATRIX::operator [] ( long i ){	return C[i];}//compareconst bool MATRIX::operator == ( const MATRIX& m ) const{	return C[0]==m.C[0] && C[1]==m.C[1] && C[2]==m.C[2];}const bool MATRIX::operator != ( const MATRIX& m ) const{	return !(m == *this);}//assignconst MATRIX& MATRIX::operator = ( const MATRIX& m ){	C[0] = m.C[0];	C[1] = m.C[1];	C[2] = m.C[2];	return *this;}//incrementconst MATRIX& MATRIX::operator +=( const MATRIX& m ){	C[0] += m.C[0];	C[1] += m.C[1];	C[2] += m.C[2];	return *this;}//decrementconst MATRIX& MATRIX::operator -=( const MATRIX& m ) {	C[0] -= m.C[0];	C[1] -= m.C[1];	C[2] -= m.C[2];	return *this;}//self-multiply by a scalarconst MATRIX& MATRIX::operator *= ( const SCALAR& s ){	C[0] *= s;	C[1] *= s;	C[2] *= s;	return *this;}//self-multiply by a matrixconst MATRIX& MATRIX::operator *= ( const MATRIX& m ){	//NOTE: don't change the columns	//in the middle of the operation	MATRIX temp = (*this);	C[0] = temp * m.C[0];	C[1] = temp * m.C[1];	C[2] = temp * m.C[2];	return *this;}//addconst MATRIX MATRIX::operator + ( const MATRIX& m ) const{	return MATRIX( C[0] + m.C[0], C[1] + m.C[1], C[2] + m.C[2] );}//subtractconst MATRIX MATRIX::operator - ( const MATRIX& m ) const{	return MATRIX( C[0] - m.C[0], C[1] - m.C[1], C[2] - m.C[2] );}//post-multiply by a scalarconst MATRIX MATRIX::operator * ( const SCALAR& s ) const{	return MATRIX( C[0]*s, C[1]*s, C[2]*s );}//post-multiply by a vectorconst VECTOR MATRIX::operator * ( const VECTOR& v ) const{	return( C[0]*v.x + C[1]*v.y + C[2]*v.z );}	//post-multiply by a matrixconst MATRIX MATRIX::operator * ( const MATRIX& m ) const{	return MATRIX( (*this) * m.C[0], (*this) * m.C[1], (*this) * m.C[2] );}//transposeMATRIX MATRIX::transpose() const{	//turn columns on their side	return MATRIX( VECTOR( C[0].x, C[1].x, C[2].x ), //column 0		VECTOR( C[0].y, C[1].y, C[2].y ), //column 1		VECTOR( C[0].z, C[1].z, C[2].z ) //column 2		);}//scalar determinantconst SCALAR MATRIX::determinant() const{	//Lang, "Linear Algebra", p. 143	return C[0].dot( C[1].cross(C[2]) );}