Method Inverse

renderdoc/maths/matrix.cpp:99–158

}

Matrix4f Matrix4f::Inverse() const
{
  float a0 = (*this)[0] * (*this)[5] - (*this)[1] * (*this)[4];
  float a1 = (*this)[0] * (*this)[6] - (*this)[2] * (*this)[4];
  float a2 = (*this)[0] * (*this)[7] - (*this)[3] * (*this)[4];
  float a3 = (*this)[1] * (*this)[6] - (*this)[2] * (*this)[5];
  float a4 = (*this)[1] * (*this)[7] - (*this)[3] * (*this)[5];
  float a5 = (*this)[2] * (*this)[7] - (*this)[3] * (*this)[6];
  float b0 = (*this)[8] * (*this)[13] - (*this)[9] * (*this)[12];
  float b1 = (*this)[8] * (*this)[14] - (*this)[10] * (*this)[12];
  float b2 = (*this)[8] * (*this)[15] - (*this)[11] * (*this)[12];
  float b3 = (*this)[9] * (*this)[14] - (*this)[10] * (*this)[13];
  float b4 = (*this)[9] * (*this)[15] - (*this)[11] * (*this)[13];
  float b5 = (*this)[10] * (*this)[15] - (*this)[11] * (*this)[14];

  float det = a0 * b5 - a1 * b4 + a2 * b3 + a3 * b2 - a4 * b1 + a5 * b0;
  if(fabsf(det) > FLT_EPSILON)
  {
    Matrix4f inverse;
    inverse[0] = +(*this)[5] * b5 - (*this)[6] * b4 + (*this)[7] * b3;
    inverse[4] = -(*this)[4] * b5 + (*this)[6] * b2 - (*this)[7] * b1;
    inverse[8] = +(*this)[4] * b4 - (*this)[5] * b2 + (*this)[7] * b0;
    inverse[12] = -(*this)[4] * b3 + (*this)[5] * b1 - (*this)[6] * b0;
    inverse[1] = -(*this)[1] * b5 + (*this)[2] * b4 - (*this)[3] * b3;
    inverse[5] = +(*this)[0] * b5 - (*this)[2] * b2 + (*this)[3] * b1;
    inverse[9] = -(*this)[0] * b4 + (*this)[1] * b2 - (*this)[3] * b0;
    inverse[13] = +(*this)[0] * b3 - (*this)[1] * b1 + (*this)[2] * b0;
    inverse[2] = +(*this)[13] * a5 - (*this)[14] * a4 + (*this)[15] * a3;
    inverse[6] = -(*this)[12] * a5 + (*this)[14] * a2 - (*this)[15] * a1;
    inverse[10] = +(*this)[12] * a4 - (*this)[13] * a2 + (*this)[15] * a0;
    inverse[14] = -(*this)[12] * a3 + (*this)[13] * a1 - (*this)[14] * a0;
    inverse[3] = -(*this)[9] * a5 + (*this)[10] * a4 - (*this)[11] * a3;
    inverse[7] = +(*this)[8] * a5 - (*this)[10] * a2 + (*this)[11] * a1;
    inverse[11] = -(*this)[8] * a4 + (*this)[9] * a2 - (*this)[11] * a0;
    inverse[15] = +(*this)[8] * a3 - (*this)[9] * a1 + (*this)[10] * a0;

    float invDet = 1.0f / det;
    inverse[0] *= invDet;
    inverse[1] *= invDet;
    inverse[2] *= invDet;
    inverse[3] *= invDet;
    inverse[4] *= invDet;
    inverse[5] *= invDet;
    inverse[6] *= invDet;
    inverse[7] *= invDet;
    inverse[8] *= invDet;
    inverse[9] *= invDet;
    inverse[10] *= invDet;
    inverse[11] *= invDet;
    inverse[12] *= invDet;
    inverse[13] *= invDet;
    inverse[14] *= invDet;
    inverse[15] *= invDet;

    return inverse;
  }

  // no inverse