int fetch_()
{
std::streamsize num = std::min(
static_cast< std::streamsize >( gptr() - eback() ), pb_size);
std::memmove(
buffer_ + ( pb_size - num),
gptr() - num, num);
s_.async_read_some(
boost::asio::buffer( buffer_ + pb_size, bf_size - pb_size),
boost::bind( & coro_t::operator(), & coro_, _1, _2) );
ca_();
boost::system::error_code ec;
std::size_t n = 0;
boost::tie( ec, n) = ca_.get();
if ( ec)
{
setg( 0, 0, 0);
return -1;
}
setg( buffer_ + pb_size - num, buffer_ + pb_size, buffer_ + pb_size + n);
return n;
}
void get()
{
// Must not hold shared_ptr to coro while suspended.
handler_.coro_.reset();
if (--ready_ != 0)
ca_();
if (!out_ec_ && ec_) throw boost::system::system_error(ec_);
}
return_type get()
{
// Must not hold shared_ptr to coro while suspended.
handler_.coro_.reset();
if (--ready_ != 0)
ca_();
if (!out_ec_ && ec_) throw boost::system::system_error(ec_);
return BOOST_ASIO_MOVE_CAST(return_type)(value_);
}
std::list<Vec3f> Mesher::get_contour()
{
// Find all of the singular edges in this fan
// (edges that aren't shared between multiple triangles).
std::set<std::array<float, 6>> valid_edges;
for (auto itr=voxel_start; itr != voxel_end; ++itr)
{
if (valid_edges.count(itr->ba_()))
valid_edges.erase(itr->ba_());
else
valid_edges.insert(itr->ab_());
if (valid_edges.count(itr->cb_()))
valid_edges.erase(itr->cb_());
else
valid_edges.insert(itr->bc_());
if (valid_edges.count(itr->ac_()))
valid_edges.erase(itr->ac_());
else
valid_edges.insert(itr->ca_());
}
std::set<std::array<float, 3>> in_fan;
std::list<Vec3f> contour = {voxel_start->a};
in_fan.insert(voxel_start->a_());
in_fan.insert(voxel_start->b_());
in_fan.insert(voxel_start->c_());
fan_start = voxel_start;
voxel_start++;
while (contour.size() == 1 || contour.front() != contour.back())
{
std::list<Triangle>::iterator itr;
for (itr=fan_start; itr != voxel_end; ++itr)
{
const auto& t = *itr;
if (contour.back() == t.a && valid_edges.count(t.ab_()))
{
contour.push_back(t.b);
break;
}
if (contour.back() == t.b && valid_edges.count(t.bc_()))
{
contour.push_back(t.c);
break;
}
if (contour.back() == t.c && valid_edges.count(t.ca_()))
{
contour.push_back(t.a);
break;
}
}
// If we broke out of the loop (meaning itr is pointing to a relevant
// triangle which should be moved forward to before voxel_start), then
// push the list around and update iterators appropriately.
if (itr != voxel_end)
{
in_fan.insert(itr->a_());
in_fan.insert(itr->b_());
in_fan.insert(itr->c_());
if (itr == voxel_start)
{
voxel_start++;
}
else if (itr != fan_start)
{
const Triangle t = *itr;
triangles.insert(voxel_start, t);
itr = triangles.erase(itr);
itr--;
}
}
}
// Special case to catch triangles that are part of a particular fan but
// don't have any edges in the contour (which can happen!).
for (auto itr=voxel_start; itr != voxel_end; ++itr)
{
if (in_fan.count(itr->a_()) &&
in_fan.count(itr->b_()) &&
in_fan.count(itr->c_()))
{
if (itr == voxel_start)
{
voxel_start++;
}
else if (itr != fan_start)
{
const Triangle t = *itr;
triangles.insert(voxel_start, t);
itr = triangles.erase(itr);
itr--;
}
}
}
// Remove the last point of the contour, since it's a closed loop.
contour.pop_back();
return contour;
}
