[patch] Fix ships restarting at 0 speed upon loading game

[TurfIt]

Upon loading a game, any ships that are moving on the open sea start over at 0 speed. Actually, they 'jump' as though you had opened/closed the schedule for each ship. Ships in canals behave.

Code Select Expand


vehicle/simvehikel.cc:944
vehikel_t::hop_check()
if((dir&new_dir)==0) {
// new one way sign here?
cnv->suche_neue_route();
return false;
}

is triggering a new route search because

Code Select Expand


vehicle/simvehikel.cc:612
vehikel_t::set_convoi(
grund_t const* const gr = welt->lookup(pos_next);
if (!gr || !gr->get_weg(get_waytype())) {
pos_next = r.position_bei(route_index + 1U);
}

is corrupting pos_next. After this call, pos_next is set equal to the current position which confuses the first code block, causing the unnecessary route search. This would be fine if the convoi was saved with broken coordinates as set_convoi expects at this point. However, it still triggers with valid coordinates.

The problem is open sea tiles don't require a weg for ships to transverse them. Patch to fix attached.