Method inverse

core/math/Mat4.cpp:650–697

}

bool Mat4::inverse()
{
    float a0 = m[0] * m[5] - m[1] * m[4];
    float a1 = m[0] * m[6] - m[2] * m[4];
    float a2 = m[0] * m[7] - m[3] * m[4];
    float a3 = m[1] * m[6] - m[2] * m[5];
    float a4 = m[1] * m[7] - m[3] * m[5];
    float a5 = m[2] * m[7] - m[3] * m[6];
    float b0 = m[8] * m[13] - m[9] * m[12];
    float b1 = m[8] * m[14] - m[10] * m[12];
    float b2 = m[8] * m[15] - m[11] * m[12];
    float b3 = m[9] * m[14] - m[10] * m[13];
    float b4 = m[9] * m[15] - m[11] * m[13];
    float b5 = m[10] * m[15] - m[11] * m[14];

    // Calculate the determinant.
    float det = a0 * b5 - a1 * b4 + a2 * b3 + a3 * b2 - a4 * b1 + a5 * b0;

    // Close to zero, can't invert.
    if (std::abs(det) <= MATH_TOLERANCE)
        return false;

    // Support the case where m == dst.
    Mat4 inverse;
    inverse.m[0] = m[5] * b5 - m[6] * b4 + m[7] * b3;
    inverse.m[1] = -m[1] * b5 + m[2] * b4 - m[3] * b3;
    inverse.m[2] = m[13] * a5 - m[14] * a4 + m[15] * a3;
    inverse.m[3] = -m[9] * a5 + m[10] * a4 - m[11] * a3;

    inverse.m[4] = -m[4] * b5 + m[6] * b2 - m[7] * b1;
    inverse.m[5] = m[0] * b5 - m[2] * b2 + m[3] * b1;
    inverse.m[6] = -m[12] * a5 + m[14] * a2 - m[15] * a1;
    inverse.m[7] = m[8] * a5 - m[10] * a2 + m[11] * a1;

    inverse.m[8]  = m[4] * b4 - m[5] * b2 + m[7] * b0;
    inverse.m[9]  = -m[0] * b4 + m[1] * b2 - m[3] * b0;
    inverse.m[10] = m[12] * a4 - m[13] * a2 + m[15] * a0;
    inverse.m[11] = -m[8] * a4 + m[9] * a2 - m[11] * a0;

    inverse.m[12] = -m[4] * b3 + m[5] * b1 - m[6] * b0;
    inverse.m[13] = m[0] * b3 - m[1] * b1 + m[2] * b0;
    inverse.m[14] = -m[12] * a3 + m[13] * a1 - m[14] * a0;
    inverse.m[15] = m[8] * a3 - m[9] * a1 + m[10] * a0;

    multiply(inverse, 1.0f / det, this);

    return true;
}

bool Mat4::isIdentity() const
{