float Matrix4::Determinant() const
{
return
m[0][0] * MinorDeterminant(1, 2, 3, 1, 2, 3) -
m[0][1] * MinorDeterminant(1, 2, 3, 0, 2, 3) +
m[0][2] * MinorDeterminant(1, 2, 3, 0, 1, 3) -
m[0][3] * MinorDeterminant(1, 2, 3, 0, 1, 2);
}
static Matrix4x4 MatAdjoint(const Matrix4x4* pkMat)
{
// COMMENT : http://www.codeproject.com/csharp/Matrix.asp
Matrix4x4 kMatRet;
for(UINT32 r = 0; r < 4; ++r)
{
for(UINT32 c = 0; c < 4; ++c)
{
kMatRet.m[c][r] = powf(-1.0f, (FLOAT32)(r + c)) * MinorDeterminant(*pkMat, r, c);
}
}
return kMatRet;
}
Matrix4 Matrix4::Inverse() const
{
float minorDeterminant123123 = MinorDeterminant(1, 2, 3, 1, 2, 3);
float minorDeterminant123023 = MinorDeterminant(1, 2, 3, 0, 2, 3);
float minorDeterminant123013 = MinorDeterminant(1, 2, 3, 0, 1, 3);
float minorDeterminant123012 = MinorDeterminant(1, 2, 3, 0, 1, 2);
float determinant =
m[0][0] * minorDeterminant123123 -
m[0][1] * minorDeterminant123023 +
m[0][2] * minorDeterminant123013 -
m[0][3] * minorDeterminant123012;
Matrix4 adjoint(
minorDeterminant123123,
-MinorDeterminant(0, 2, 3, 1, 2, 3),
MinorDeterminant(0, 1, 3, 1, 2, 3),
-MinorDeterminant(0, 1, 2, 1, 2, 3),
-minorDeterminant123023,
MinorDeterminant(0, 2, 3, 0, 2, 3),
-MinorDeterminant(0, 1, 3, 0, 2, 3),
MinorDeterminant(0, 1, 2, 0, 2, 3),
minorDeterminant123013,
-MinorDeterminant(0, 2, 3, 0, 1, 3),
MinorDeterminant(0, 1, 3, 0, 1, 3),
-MinorDeterminant(0, 1, 2, 0, 1, 3),
-minorDeterminant123012,
MinorDeterminant(0, 2, 3, 0, 1, 2),
-MinorDeterminant(0, 1, 3, 0, 1, 2),
MinorDeterminant(0, 1, 2, 0, 1, 2));
return adjoint * (1.0f / determinant);
}
Matrix4 Matrix4::Adjoint() const
{
return Matrix4(
MinorDeterminant(1, 2, 3, 1, 2, 3),
-MinorDeterminant(0, 2, 3, 1, 2, 3),
MinorDeterminant(0, 1, 3, 1, 2, 3),
-MinorDeterminant(0, 1, 2, 1, 2, 3),
-MinorDeterminant(1, 2, 3, 0, 2, 3),
MinorDeterminant(0, 2, 3, 0, 2, 3),
-MinorDeterminant(0, 1, 3, 0, 2, 3),
MinorDeterminant(0, 1, 2, 0, 2, 3),
MinorDeterminant(1, 2, 3, 0, 1, 3),
-MinorDeterminant(0, 2, 3, 0, 1, 3),
MinorDeterminant(0, 1, 3, 0, 1, 3),
-MinorDeterminant(0, 1, 2, 0, 1, 3),
-MinorDeterminant(1, 2, 3, 0, 1, 2),
MinorDeterminant(0, 2, 3, 0, 1, 2),
-MinorDeterminant(0, 1, 3, 0, 1, 2),
MinorDeterminant(0, 1, 2, 0, 1, 2));
}