/**
* Converts all trains to the new subtype format introduced in savegame 16.2
* It also links multiheaded engines or make them forget they are multiheaded if no suitable partner is found
*/
void ConvertOldMultiheadToNew()
{
Train *t;
FOR_ALL_TRAINS(t) SetBit(t->subtype, 7); // indicates that it's the old format and needs to be converted in the next loop
FOR_ALL_TRAINS(t) {
if (HasBit(t->subtype, 7) && ((t->subtype & ~0x80) == 0 || (t->subtype & ~0x80) == 4)) {
for (Train *u = t; u != NULL; u = u->Next()) {
const RailVehicleInfo *rvi = RailVehInfo(u->engine_type);
ClrBit(u->subtype, 7);
switch (u->subtype) {
case 0: // TS_Front_Engine
if (rvi->railveh_type == RAILVEH_MULTIHEAD) u->SetMultiheaded();
u->SetFrontEngine();
u->SetEngine();
break;
case 1: // TS_Artic_Part
u->subtype = 0;
u->SetArticulatedPart();
break;
case 2: // TS_Not_First
u->subtype = 0;
if (rvi->railveh_type == RAILVEH_WAGON) {
/* normal wagon */
u->SetWagon();
break;
}
if (rvi->railveh_type == RAILVEH_MULTIHEAD && rvi->image_index == u->spritenum - 1) {
/* rear end of a multiheaded engine */
u->SetMultiheaded();
break;
}
if (rvi->railveh_type == RAILVEH_MULTIHEAD) u->SetMultiheaded();
u->SetEngine();
break;
case 4: // TS_Free_Car
u->subtype = 0;
u->SetWagon();
u->SetFreeWagon();
break;
default: NOT_REACHED();
}
}
}
}
}
/*
* Link front and rear multiheaded engines to each other
* This is done when loading a savegame
*/
void ConnectMultiheadedTrains()
{
Train *v;
FOR_ALL_TRAINS(v) {
v->other_multiheaded_part = NULL;
}
FOR_ALL_TRAINS(v) {
if (v->IsFrontEngine() || v->IsFreeWagon()) {
/* Two ways to associate multiheaded parts to each other:
* sequential-matching: Trains shall be arranged to look like <..>..<..>..<..>..
* bracket-matching: Free vehicle chains shall be arranged to look like ..<..<..>..<..>..>..
*
* Note: Old savegames might contain chains which do not comply with these rules, e.g.
* - the front and read parts have invalid orders
* - different engine types might be combined
* - there might be different amounts of front and rear parts.
*
* Note: The multiheaded parts need to be matched exactly like they are matched on the server, else desyncs will occur.
* This is why two matching strategies are needed.
*/
bool sequential_matching = v->IsFrontEngine();
for (Train *u = v; u != NULL; u = u->GetNextVehicle()) {
if (u->other_multiheaded_part != NULL) continue; // we already linked this one
if (u->IsMultiheaded()) {
if (!u->IsEngine()) {
/* we got a rear car without a front car. We will convert it to a front one */
u->SetEngine();
u->spritenum--;
}
/* Find a matching back part */
EngineID eid = u->engine_type;
Train *w;
if (sequential_matching) {
for (w = u->GetNextVehicle(); w != NULL; w = w->GetNextVehicle()) {
if (w->engine_type != eid || w->other_multiheaded_part != NULL || !w->IsMultiheaded()) continue;
/* we found a car to partner with this engine. Now we will make sure it face the right way */
if (w->IsEngine()) {
w->ClearEngine();
w->spritenum++;
}
break;
}
} else {
uint stack_pos = 0;
for (w = u->GetNextVehicle(); w != NULL; w = w->GetNextVehicle()) {
if (w->engine_type != eid || w->other_multiheaded_part != NULL || !w->IsMultiheaded()) continue;
if (w->IsEngine()) {
stack_pos++;
} else {
if (stack_pos == 0) break;
stack_pos--;
}
}
}
if (w != NULL) {
w->other_multiheaded_part = u;
u->other_multiheaded_part = w;
} else {
/* we got a front car and no rear cars. We will fake this one for forget that it should have been multiheaded */
u->ClearMultiheaded();
}
}
}
}
}
}