(svn r15378) -Fix: The subcargo returned by vehicle variable 0x42 should be the most-common-subcargo of the most-common-cargo. If nothing is transported 0x..FFFF00 should be returned.

1 files changed, 14 insertions, 5 deletions

diff --git a/src/newgrf_engine.cpp b/src/newgrf_engine.cpp
index bde2fd56e..13bc537aa 100644
--- a/src/newgrf_engine.cpp
+++ b/src/newgrf_engine.cpp
@@ -485,9 +485,9 @@ static uint32 VehicleGetVariable(const ResolverObject *object, byte variable, by
 		case 0x42: { // Consist cargo information
 			const Vehicle *u;
 			byte cargo_classes = 0;
-			uint8 common_cargo_best = 0;
+			CargoID common_cargo_best = CT_INVALID;
 			uint8 common_cargos[NUM_CARGO];
-			uint8 common_subtype_best = 0;
+			uint8 common_subtype_best = 0xFF; // Return 0xFF if nothing is carried
 			uint8 common_subtypes[256];
 			byte user_def_data = 0;
 			CargoID common_cargo_type = CT_PASSENGERS;
@@ -505,17 +505,25 @@ static uint32 VehicleGetVariable(const ResolverObject *object, byte variable, by
 
 				cargo_classes |= GetCargo(u->cargo_type)->classes;
 				common_cargos[u->cargo_type]++;
-				common_subtypes[u->cargo_subtype]++;
 			}
 
 			/* Pick the most common cargo type */
 			for (CargoID cargo = 0; cargo < NUM_CARGO; cargo++) {
 				if (common_cargos[cargo] > common_cargo_best) {
 					common_cargo_best = common_cargos[cargo];
-					common_cargo_type = GetCargo(cargo)->bitnum;
+					common_cargo_type = cargo;
 				}
 			}
 
+			/* Count subcargo types of common_cargo_type */
+			for (u = v; u != NULL; u = u->Next()) {
+				/* Skip empty engines and engines not carrying common_cargo_type */
+				if (u->cargo_cap == 0 || u->cargo_type != common_cargo_type) continue;
+
+				common_subtypes[u->cargo_subtype]++;
+			}
+
+			/* Pick the most common subcargo type*/
 			for (uint i = 0; i < lengthof(common_subtypes); i++) {
 				if (common_subtypes[i] > common_subtype_best) {
 					common_subtype_best = common_subtypes[i];
@@ -523,7 +531,8 @@ static uint32 VehicleGetVariable(const ResolverObject *object, byte variable, by
 				}
 			}
 
-			return cargo_classes | (common_cargo_type << 8) | (common_subtype << 16) | (user_def_data << 24);
+			uint8 common_bitnum = (common_cargo_type == CT_INVALID ? 0xFF : GetCargo(common_cargo_type)->bitnum);
+			return cargo_classes | (common_bitnum << 8) | (common_subtype << 16) | (user_def_data << 24);
 		}
 
 		case 0x43: // Company information