void dgMatrix::PolarDecomposition (dgMatrix& transformMatrix, dgVector& scale, dgMatrix& stretchAxis, const dgMatrix* const initialStretchAxis) const { // a polar decomposition decompose matrix A = O * S // where S = sqrt (transpose (L) * L) /* // calculate transpose (L) * L dgMatrix LL ((*this) * Transpose()); // check is this is a pure uniformScale * rotation * translation dgFloat32 det2 = (LL[0][0] + LL[1][1] + LL[2][2]) * dgFloat32 (1.0f / 3.0f); dgFloat32 invdet2 = 1.0f / det2; dgMatrix pureRotation (LL); pureRotation[0] = pureRotation[0].Scale3 (invdet2); pureRotation[1] = pureRotation[1].Scale3 (invdet2); pureRotation[2] = pureRotation[2].Scale3 (invdet2); dgFloat32 sign = ((((*this)[0] * (*this)[1]) % (*this)[2]) > 0.0f) ? 1.0f : -1.0f; dgFloat32 det = (pureRotation[0] * pureRotation[1]) % pureRotation[2]; if (dgAbsf (det - dgFloat32 (1.0f)) < dgFloat32 (1.0e-5f)) { // this is a pure scale * rotation * translation det = sign * dgSqrt (det2); scale[0] = det; scale[1] = det; scale[2] = det; det = dgFloat32 (1.0f)/ det; transformMatrix.m_front = m_front.Scale3 (det); transformMatrix.m_up = m_up.Scale3 (det); transformMatrix.m_right = m_right.Scale3 (det); transformMatrix[0][3] = dgFloat32 (0.0f); transformMatrix[1][3] = dgFloat32 (0.0f); transformMatrix[2][3] = dgFloat32 (0.0f); transformMatrix.m_posit = m_posit; stretchAxis = dgGetIdentityMatrix(); } else { stretchAxis = LL; stretchAxis.EigenVectors (scale); // I need to deal with by seeing of some of the Scale are duplicated // do this later (maybe by a given rotation around the non uniform axis but I do not know if it will work) // for now just us the matrix scale[0] = sign * dgSqrt (scale[0]); scale[1] = sign * dgSqrt (scale[1]); scale[2] = sign * dgSqrt (scale[2]); scale[3] = dgFloat32 (0.0f); dgMatrix scaledAxis; scaledAxis[0] = stretchAxis[0].Scale3 (dgFloat32 (1.0f) / scale[0]); scaledAxis[1] = stretchAxis[1].Scale3 (dgFloat32 (1.0f) / scale[1]); scaledAxis[2] = stretchAxis[2].Scale3 (dgFloat32 (1.0f) / scale[2]); scaledAxis[3] = stretchAxis[3]; dgMatrix symetricInv (stretchAxis.Transpose() * scaledAxis); transformMatrix = symetricInv * (*this); transformMatrix.m_posit = m_posit; } */ // test the f*****g factorization dgMatrix xxxxx(dgRollMatrix(30.0f * 3.1416f / 180.0f)); xxxxx = dgYawMatrix(30.0f * 3.1416f / 180.0f) * xxxxx; dgMatrix xxxxx1(dgGetIdentityMatrix()); xxxxx1[0][0] = 2.0f; dgMatrix xxxxx2(xxxxx.Inverse() * xxxxx1 * xxxxx); dgMatrix xxxxx3 (xxxxx2); xxxxx2.EigenVectors(scale); dgMatrix xxxxx4(xxxxx2.Inverse() * xxxxx1 * xxxxx2); //dgFloat32 sign = ((((*this)[0] * (*this)[1]) % (*this)[2]) > 0.0f) ? 1.0f : -1.0f; dgFloat32 sign = dgSign(((*this)[0] * (*this)[1]) % (*this)[2]); stretchAxis = (*this) * Transpose(); stretchAxis.EigenVectors (scale); // I need to deal with by seeing of some of the Scale are duplicated // do this later (maybe by a given rotation around the non uniform axis but I do not know if it will work) // for now just us the matrix scale[0] = sign * dgSqrt (scale[0]); scale[1] = sign * dgSqrt (scale[1]); scale[2] = sign * dgSqrt (scale[2]); scale[3] = dgFloat32 (0.0f); dgMatrix scaledAxis; scaledAxis[0] = stretchAxis[0].Scale3 (dgFloat32 (1.0f) / scale[0]); scaledAxis[1] = stretchAxis[1].Scale3 (dgFloat32 (1.0f) / scale[1]); scaledAxis[2] = stretchAxis[2].Scale3 (dgFloat32 (1.0f) / scale[2]); scaledAxis[3] = stretchAxis[3]; dgMatrix symetricInv (stretchAxis.Transpose() * scaledAxis); transformMatrix = symetricInv * (*this); transformMatrix.m_posit = m_posit; }