(svn r10222) -Fix [FS#892]: Only 2 trains could crash at one time as collision checking stopped on the first hit. This could cause desyncs in network games as the collision hash order is not guaranteed. (patch by B. N. Smatz)

1 files changed, 47 insertions, 41 deletions

diff --git a/src/train_cmd.cpp b/src/train_cmd.cpp
index f04121db6..0aca1b08d 100644
--- a/src/train_cmd.cpp
+++ b/src/train_cmd.cpp
@@ -2659,28 +2659,6 @@ static void TrainMovedChangeSignals(TileIndex tile, DiagDirection dir)
 }
 
 
-struct TrainCollideChecker {
-	const Vehicle *v;
-	const Vehicle *v_skip;
-};
-
-static void *FindTrainCollideEnum(Vehicle *v, void *data)
-{
-	const TrainCollideChecker* tcc = (TrainCollideChecker*)data;
-
-	if (v != tcc->v &&
-			v != tcc->v_skip &&
-			v->type == VEH_TRAIN &&
-			v->u.rail.track != TRACK_BIT_DEPOT &&
-			myabs(v->z_pos - tcc->v->z_pos) < 6 &&
-			myabs(v->x_pos - tcc->v->x_pos) < 6 &&
-			myabs(v->y_pos - tcc->v->y_pos) < 6) {
-		return v;
-	} else {
-		return NULL;
-	}
-}
-
 static void SetVehicleCrashed(Vehicle *v)
 {
 	if (v->u.rail.crash_anim_pos != 0) return;
@@ -2704,6 +2682,47 @@ static uint CountPassengersInTrain(const Vehicle* v)
 	return num;
 }
 
+struct TrainCollideChecker {
+	Vehicle *v;
+	const Vehicle *v_skip;
+	uint num;
+};
+
+static void *FindTrainCollideEnum(Vehicle *v, void *data)
+{
+	TrainCollideChecker* tcc = (TrainCollideChecker*)data;
+
+	if (v != tcc->v &&
+			v != tcc->v_skip &&
+			v->type == VEH_TRAIN &&
+			v->u.rail.track != TRACK_BIT_DEPOT &&
+			myabs(v->z_pos - tcc->v->z_pos) < 6 &&
+			myabs(v->x_pos - tcc->v->x_pos) < 6 &&
+			myabs(v->y_pos - tcc->v->y_pos) < 6 ) {
+
+		Vehicle *coll = GetFirstVehicleInChain(v);
+
+		/* it can't collide with its own wagons */
+		if (tcc->v == coll ||
+			(tcc->v->u.rail.track == TRACK_BIT_WORMHOLE && (tcc->v->direction & 2) != (v->direction & 2)))
+			return NULL;
+
+		/* two drivers + passengers killed in train tcc->v (if it was not crashed already) */
+		if (!(tcc->v->vehstatus & VS_CRASHED)) {
+			tcc->num += 2 + CountPassengersInTrain(tcc->v);
+			SetVehicleCrashed(tcc->v);
+		}
+
+		if (!(coll->vehstatus & VS_CRASHED)) {
+			/* two drivers + passengers killed in train coll (if it was not crashed already) */
+			tcc->num += 2 + CountPassengersInTrain(coll);
+			SetVehicleCrashed(coll);
+		}
+	}
+
+	return NULL;
+}
+
 /**
  * Checks whether the specified train has a collision with another vehicle. If
  * so, destroys this vehicle, and the other vehicle if its subtype has TS_Front.
@@ -2720,28 +2739,15 @@ static void CheckTrainCollision(Vehicle *v)
 	TrainCollideChecker tcc;
 	tcc.v = v;
 	tcc.v_skip = v->next;
+	tcc.num = 0;
 
-	/* find colliding vehicle */
-	Vehicle *realcoll = (Vehicle*)VehicleFromPosXY(v->x_pos, v->y_pos, &tcc, FindTrainCollideEnum);
-	if (realcoll == NULL) return;
-
-	Vehicle *coll = GetFirstVehicleInChain(realcoll);
-
-	/* it can't collide with its own wagons */
-	if (v == coll ||
-			(v->u.rail.track == TRACK_BIT_WORMHOLE && (v->direction & 2) != (realcoll->direction & 2)))
-		return;
-
-	/* two drivers + passengers killed in train v */
-	uint num = 2 + CountPassengersInTrain(v);
-	if (!(coll->vehstatus & VS_CRASHED))
-		/* two drivers + passengers killed in train coll (if it was not crashed already) */
-		num += 2 + CountPassengersInTrain(coll);
+	/* find colliding vehicles */
+	VehicleFromPosXY(v->x_pos, v->y_pos, &tcc, FindTrainCollideEnum);
 
-	SetVehicleCrashed(v);
-	if (IsFrontEngine(coll)) SetVehicleCrashed(coll);
+	/* any dead -> no crash */
+	if (tcc.num == 0) return;
 
-	SetDParam(0, num);
+	SetDParam(0, tcc.num);
 	AddNewsItem(STR_8868_TRAIN_CRASH_DIE_IN_FIREBALL,
 		NEWS_FLAGS(NM_THIN, NF_VIEWPORT | NF_VEHICLE, NT_ACCIDENT, 0),
 		v->index,