gistfile1.txt

static unsigned get_neighbor_bits(wire_pos w) {
    unsigned bits = 0u;
    auto bl = ship->get_block(w.pos);
    for (auto i = 0u; i < 6u; i++) {
        if (i == w.face || i == (w.face ^ 1)) continue;
        if (bl->surfs[i]) {
            // inside corner
            if (bl->has_wire[i]) {
                bits |= 1 << i;
            }
        }
        else {
            auto np = w.pos + surface_index_to_normal(i);
            auto n = ship->get_block(np);
            if (n && n->surfs[w.face]) {
                // straight along surface
                if (n->has_wire[w.face]) {
                    bits |= 1 << i;
                }
            }
            else {
                auto rp = np + surface_index_to_normal(w.face);
                auto r = ship->get_block(rp);
                if (r && r->surfs[i ^ 1]) {
                    // outside corner
                    if (r->has_wire[w.face]) {
                        bits |= 1 << i;
                    }
                }
            }
        }
    }
    return bits;
}

\o/ this is actually buggy. last has_wire[w.face] should be has_wire[i ^ 1]