Function xQuickCullForBox

src/SB/Core/x/xCollide.cpp:2670–2672

    F32 f31 = d1.length2();
    F32 b = 2.0f * d1.dot(d2);
    F32 q = SQR(b) - 4.0f * f31 * (d2.length2() - SQR(r));

    if (q < 0.0f)
        return false;

    F32 d = xsqrt(q);