(svn r266) -Fix: hopefully fixed the desync problem nicely (and reverted the

workaround for it)

economy.c

@@ -1208,10 +1208,12 @@ int LoadUnloadVehicle(Vehicle *v)
 	GoodsEntry *ge;
 	int t;
 	uint count, cap;
+	byte old_player;
 
 	assert((v->next_order&0x1F) == OT_LOADING);
 
 	v->cur_speed = 0;
+	old_player = _current_player;
 	_current_player = v->owner;
 
 	st = DEREF_STATION(last_visited = v->last_station_visited);
@@ -1318,6 +1320,7 @@ next_vehicle:;
 		}
 	}
 
+	_current_player = old_player;
 	return result;
 }
 

misc.c

@@ -15,15 +15,20 @@ static INLINE uint32 ROR(uint32 x, int n)
 	return (x >> n) + (x << ((sizeof(x)*8)-n));
 }
 
-/* Fuck bitch code, most probably one of the loops (tileloop, vehicleloop, etc.) 
- * doesn't set up/reset _current_player so the normal random below fails #$%@$#!
- * The old code below is prune to desyncs because randoms interfere.
- * SO FIND THE OFFENDING LOOP AND FIX IT ONCE AND FOR ALL */
-#undef NORMAL_RANDOM // unuseable game, desyncs way too fast
+// For multiplayer, we introduced this new way of random-seeds
+//  It is player-based, so 2 clients can do 2 commands at the same time
+//  without the game desyncing.
+// It is not used for non-multiplayer games
+#ifdef ENABLE_NETWORK
+	#define PLAYER_SEED_RANDOM
+#else
+	#undef PLAYER_SEED_RANDOM
+#endif
+
 uint32 Random()
 {
-#ifdef NORMAL_RANDOM
-	if (_current_player>=MAX_PLAYERS) {
+#ifdef PLAYER_SEED_RANDOM
+	if (_current_player>=MAX_PLAYERS || !_networking) {
 		uint32 s = _random_seeds[0][0];
 		uint32 t = _random_seeds[0][1];
 		_random_seeds[0][0] = s + ROR(t ^ 0x1234567F, 7);

network.c

@@ -365,6 +365,7 @@ void NetworkProcessCommands()
 {
 	CommandQueue *nq;
 	QueuedCommand *qp;
+	byte old_player;
 
 	// queue mode ?
 	if (_networking_queuing)
@@ -380,11 +381,13 @@ void NetworkProcessCommands()
 		}
 
 		// run the command
+		old_player = _current_player;
 		_current_player = qp->cp.player;
 		memcpy(_decode_parameters, qp->cp.dp, (qp->cp.packet_length - COMMAND_PACKET_BASE_SIZE));
 
 		DoCommandP(qp->cp.tile, qp->cp.p1, qp->cp.p2, qp->callback, qp->cmd | CMD_DONT_NETWORK);
 		free(qp);
+		_current_player = old_player;
 	}
 
 	if (!_networking_server) {

town_cmd.c

@@ -694,6 +694,7 @@ bool GrowTown(Town *t)
 	const TileIndexDiff *ptr;
 	int offs;
 	TileInfo ti;
+	byte old_player;
 
 	static const TileIndexDiff _town_coord_mod[] = {
 		TILE_XY(-1,0),
@@ -712,6 +713,7 @@ bool GrowTown(Town *t)
 	};
 
 	// Current player is a town
+	old_player = _current_player;
 	_current_player = OWNER_TOWN;
 
 	// Find a road that we can base the construction on.
@@ -719,7 +721,9 @@ bool GrowTown(Town *t)
 	ptr = _town_coord_mod;
 	do {
 		if (GetRoadBitsByTile(tile) != 0) {
-			return GrowTownAtRoad(t, tile);
+			int r = GrowTownAtRoad(t, tile);
+			_current_player = old_player;
+			return r;
 		}
 		offs = *ptr++;
 
@@ -737,6 +741,7 @@ bool GrowTown(Town *t)
 		if (ti.tileh == 0 && !(ti.type==MP_HOUSE && ti.map5==0)) {
 			if (DoCommandByTile(tile, 0, 0, DC_AUTO, CMD_LANDSCAPE_CLEAR) != CMD_ERROR) {
 				DoCommandByTile(tile, GenRandomRoadBits(), 0, DC_EXEC | DC_AUTO, CMD_BUILD_ROAD);
+				_current_player = old_player;
 				return true;
 			}
 		}
@@ -744,6 +749,7 @@ bool GrowTown(Town *t)
 		tile = TILE_ADD(tile, offs);
 	} while (offs != 0);
 
+	_current_player = old_player;
 	return false;
 }
 

vehicle.c

@@ -1378,6 +1378,8 @@ void MaybeRenewVehicle(Vehicle *v, int32 build_cost)
 	v->value = build_cost;
 
 	InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
+
+	_current_player = OWNER_NONE;
 }