vsMatrix4x4
vsMatrix4x4::Inverse() const
{
/* NB. OpenGL Matrices are COLUMN major. */
/* Here's some shorthand converting standard (row,column) to index. */
if( m41 != 0.0f || m42 != 0.0f || m43 != 0.0f || m44 != 1.0f )
{
return InverseGeneral();
}
/* Inverse = adjoint / det. (See linear algebra texts.)*/
/* Allow out == in, but don't do an extra copy */
vsMatrix4x4 temp;
temp.x.x= m22 * m33 - m23 * m32;
temp.x.y= m23 * m31 - m21 * m33;
temp.x.z= m21 * m32 - m22 * m31;
/* Compute determinant as early as possible using these cofactors. */
register float det;
det= m11 * temp.x.x + m12 * temp.x.y + m13 * temp.x.z;
/* Run singularity test. */
if (det == 0.0)
{
vsLog("invert_matrix: Warning: Singular matrix.");
return vsMatrix4x4::Identity;
}
float d12, d13, d23, d24, d34, d41;
register float im11, im12, im13, im14;
det= 1.0f / det;
/* Compute rest of inverse. */
temp.x.x *= det;
temp.x.y *= det;
temp.x.z *= det;
temp.x.w = 0.0f;
im11= m11 * det;
im12= m12 * det;
im13= m13 * det;
im14= m14 * det;
temp.y.x = im13 * m32 - im12 * m33;
temp.y.y = im11 * m33 - im13 * m31;
temp.y.z = im12 * m31 - im11 * m32;
temp.y.w = 0.0f;
/* Pre-compute 2x2 dets for first two rows when computing */
/* cofactors of last two rows. */
d12 = im11*m22 - m21*im12;
d13 = im11*m23 - m21*im13;
d23 = im12*m23 - m22*im13;
d24 = im12*m24 - m22*im14;
d34 = im13*m24 - m23*im14;
d41 = im14*m21 - m24*im11;
temp.z.x = d23;
temp.z.y = -d13;
temp.z.z = d12;
temp.z.w = 0.0f;
temp.w.x = -(m32 * d34 - m33 * d24 + m34 * d23);
temp.w.y = (m31 * d34 + m33 * d41 + m34 * d13);
temp.w.z = -(m31 * d24 + m32 * d41 + m34 * d12);
temp.w.w = 1.0f;
#undef m11
#undef m12
#undef m13
#undef m14
#undef m21
#undef m22
#undef m23
#undef m24
#undef m31
#undef m32
#undef m33
#undef m34
#undef m41
#undef m42
#undef m43
#undef m44
return temp;
}
inline VMatrix VMatrix::operator~() const {
VMatrix mRet;
InverseGeneral( mRet );
return mRet;
}
