std::vector<int> karatsuba(const std::vector<int> &a, const std::vector<int> &b)
{
// a = a2 * k^n + a1
// b = b2 * k^n + b1
// a * b = (a2 * b2) * k^2n + (a2 * b1 + a1 * b2) * k^n + (a1 * b1)
// = (a2 * b2) * k^2n + ((a1 + a2) * (b1 + b2) - (a2 * b2) - (a1 * b1)) * k^n + (a1 * b1)
// = z0 * k^2n + z2 * k^n + z1
// z0 = a2 * b2
// z1 = a1 * b1
if (a.size() < b.size())
return karatsuba(b, a);
if (b.size() == 0)
return std::vector<int>();
//if (a.size() <= 50)
// return multiply(a, b);
if (a.size() < 3)
return multiply(a, b);
size_t half = a.size() / 2;
size_t b_half = std::min(half, size_t(b.end() - b.begin()));
std::vector<int> a1(a.begin(), a.begin() + half);
std::vector<int> a2(a.begin() + half, a.end());
std::vector<int> b1(b.begin(), b.begin() + b_half);
std::vector<int> b2(b.begin() + b_half, b.end());
std::vector<int> z0 = karatsuba(a2, b2);
std::vector<int> z1 = karatsuba(a1, b1);
std::vector<int> a3 = a1;
addTo(a3, a2, 0);
std::vector<int> b3 = b1;
addTo(b3, b2, 0);
std::vector<int> z2 = karatsuba(a3, b3);
subFrom(z2, z0, 0);
subFrom(z2, z1, 0);
std::vector<int> ret;
ret.reserve(a.size() + b.size());
addTo(ret, z1, 0);
addTo(ret, z2, half);
addTo(ret, z0, half * 2);
normalize(ret);
return ret;
}
void Barrel::calcPhys(Model *m)
{
Vec3 lob(m->lowerBound());
Vec3 upb(m->upperBound());
center_ = lob;
addTo(center_, upb);
scale(center_, 0.5f);
subFrom(upb, lob);
radius_ = std::max(upb.x, upb.y) * 0.5f;
height_ = upb.z;
}
virtual void prepare(CameraInfo const &cam)
{
Vec3 wPos(worldPos());
Vec3 back(wPos);
subFrom(back, cam_->lookAt);
normalize(back);
cam_->back = back;
Vec3 up(0, 0, 1);
Vec3 right;
cross(right, up, back);
normalize(right);
cross(up, back, right);
cam_->mmat_.setRow(0, right);
cam_->mmat_.setRow(1, up);
cam_->mmat_.setRow(2, back);
Vec3 zPos;
cam_->mmat_.setTranslation(zPos);
cam_->mmat_.setRow(3, zPos);
subFrom(zPos, wPos);
multiply(cam_->mmat_, zPos);
cam_->mmat_.setTranslation(zPos);
}
