Fix: [NewGRF] The result of Action123 evaluation affected rerandomisation in a weird corner case. (#14139)

Rerandomisation does not care about the Resolve result.
But we skipped it, in case of 'invalid SpriteGroup reference'.

src/newgrf_engine.cpp

@@ -1255,8 +1255,7 @@ static void DoTriggerVehicleRandomisation(Vehicle *v, VehicleRandomTrigger trigg
 	v->waiting_random_triggers.Set(trigger); // store now for var 5F
 	object.SetWaitingRandomTriggers(v->waiting_random_triggers);
 
-	const SpriteGroup *group = object.Resolve();
+	object.ResolveRerandomisation();
-	if (group == nullptr) return;
 
 	/* Store remaining triggers. */
 	v->waiting_random_triggers.Reset(object.GetUsedRandomTriggers());

src/newgrf_house.cpp

@@ -675,8 +675,7 @@ static void DoTriggerHouseRandomisation(TileIndex tile, HouseRandomTrigger trigg
 	SetHouseRandomTriggers(tile, waiting_random_triggers); // store now for var 5F
 	object.SetWaitingRandomTriggers(waiting_random_triggers);
 
-	const SpriteGroup *group = object.Resolve();
+	object.ResolveRerandomisation();
-	if (group == nullptr) return;
 
 	/* Store remaining triggers. */
 	waiting_random_triggers.Reset(object.GetUsedRandomTriggers());

src/newgrf_industrytiles.cpp

@@ -336,8 +336,7 @@ static void DoTriggerIndustryTileRandomisation(TileIndex tile, IndustryRandomTri
 	SetIndustryRandomTriggers(tile, waiting_random_triggers); // store now for var 5F
 	object.SetWaitingRandomTriggers(waiting_random_triggers);
 
-	const SpriteGroup *group = object.Resolve();
+	object.ResolveRerandomisation();
-	if (group == nullptr) return;
 
 	/* Store remaining triggers. */
 	waiting_random_triggers.Reset(object.GetUsedRandomTriggers());

src/newgrf_roadstop.cpp

@@ -451,8 +451,7 @@ void TriggerRoadStopRandomisation(BaseStation *st, TileIndex tile, StationRandom
 			RoadStopResolverObject object(ss, st, cur_tile, INVALID_ROADTYPE, GetStationType(cur_tile), GetStationGfx(cur_tile));
 			object.SetWaitingRandomTriggers(st->waiting_random_triggers);
 
-			const SpriteGroup *group = object.Resolve();
+			object.ResolveRerandomisation();
-			if (group == nullptr) return;
 
 			used_random_triggers.Set(object.GetUsedRandomTriggers());
 

src/newgrf_spritegroup.h

@@ -336,13 +336,27 @@ public:
 		return SpriteGroup::Resolve(this->root_spritegroup, *this);
 	}
 
+	/**
+	 * Resolve bits to be rerandomised.
+	 * Access results via:
+	 * - reseed: Bits to rerandomise per scope, for features with proper PARENT rerandomisation. (only industry tiles)
+	 * - GetReseedSum: Bits to rerandomise for SELF scope, for features with broken-by-design PARENT randomisation. (all but industry tiles)
+	 * - GetUsedRandomTriggers: Consumed random triggers to be reset.
+	 */
+	void ResolveRerandomisation()
+	{
+		/* The Resolve result has no meaning.
+		 * It can be a SpriteSet, a callback result, or even an invalid SpriteGroup reference (nullptr). */
+		this->Resolve();
+	}
+
 	/**
 	 * Resolve callback.
 	 * @return Callback result.
 	 */
 	uint16_t ResolveCallback()
 	{
-		const SpriteGroup *result = Resolve();
+		const SpriteGroup *result = this->Resolve();
 		return result != nullptr ? result->GetCallbackResult() : CALLBACK_FAILED;
 	}
 

src/newgrf_station.cpp

@@ -996,8 +996,7 @@ void TriggerStationRandomisation(BaseStation *st, TileIndex trigger_tile, Statio
 				StationResolverObject object(ss, st, tile, CBID_RANDOM_TRIGGER, 0);
 				object.SetWaitingRandomTriggers(st->waiting_random_triggers);
 
-				const SpriteGroup *group = object.Resolve();
+				object.ResolveRerandomisation();
-				if (group == nullptr) continue;
 
 				used_random_triggers.Set(object.GetUsedRandomTriggers());