bool Frustum::checkSphere(const PrimitiveSphere& sphere, const WorldPoint& were) const noexcept {

    const auto pos = were.position + sphere.center;
    for (const auto& plane : planes) {

        const float radius = sphere.radius * were.scale.unitMagnitude(); //unit magnitude is just x + y + z / 3
        const float dist =
            plane.x * pos.x +
            plane.y * pos.y +
            plane.z * pos.z + plane.w;
        if (dist < -radius)
            return false;
    }
    return true;
}

void Frustum::fromViewProj(const float* const vp) noexcept {

    const float xw = vp[3];
    const float yw = vp[7];
    const float zw = vp[11];
    const float ww = vp[15];

    const float xz = vp[2];
    const float yz = vp[6];
    const float zz = vp[10];
    const float wz = vp[14];

    PrimitivePlane& near = planes[0];
    PrimitivePlane& far = planes[1];
    PrimitivePlane& left = planes[2];
    PrimitivePlane& right = planes[3];
    PrimitivePlane& top = planes[4];
    PrimitivePlane& bottom = planes[5];

    near.x = xw - xz;
    near.y = yw - yz;
    near.z = zw - zz;
    near.w = ww - wz;

    far.x = xw + xz;
    far.y = yw + yz;
    far.z = zw + zz;
    far.w = ww + wz;

    const float xx = vp[0];
    const float yx = vp[4];
    const float zx = vp[8];
    const float wx = vp[12];

    left.x = xw - xx;
    left.y = yw - yx;
    left.z = zw - zx;
    left.w = ww - wx;

    right.x = xw + xx;
    right.y = yw + yx;
    right.z = zw + zx;
    right.w = ww + wx;

    const float xy = vp[1];
    const float yy = vp[5];
    const float zy = vp[9];
    const float wy = vp[13];

    top.x = xw + xy;
    top.y = yw + yy;
    top.z = zw + zy;
    top.w = ww + wy;

    bottom.x = xw - xy;
    bottom.y = yw - yy;
    bottom.z = zw - zy;
    bottom.w = ww - wy;

    for (auto& plane : planes)
        plane.normalize();
}