(svn r5483) -Fix: [YAPF] desync - for MP games invalidate YAPF cache on every tick to keep it exactly the same on server and clients (it doesn't fix the real source of the problem, but should solve it). Thanks TrueLight for hunting this bug.

vehicle.c

@@ -29,6 +29,8 @@
 #include "industry_map.h"
 #include "station_map.h"
 #include "water_map.h"
+#include "network.h"
+#include "yapf/yapf.h"
 
 #define INVALID_COORD (-0x8000)
 #define GEN_HASH(x,y) (((x & 0x1F80)>>7) + ((y & 0xFC0)))
@@ -611,6 +613,14 @@ void CallVehicleTicks(void)
 {
 	Vehicle *v;
 
+#ifdef ENABLE_NETWORK
+	// hotfix for desync problem:
+	//  for MP games invalidate the YAPF cache every tick to keep it exactly the same on the server and all clients
+	if (_networking) {
+		YapfNotifyTrackLayoutChange(0, 0);
+	}
+#endif //ENABLE_NETWORK
+
 	_first_veh_in_depot_list = NULL;	// now we are sure it's initialized at the start of each tick
 
 	FOR_ALL_VEHICLES(v) {