Codefix: VehiclesNearTileXY yielded all vehicles with matching hashes, even if they are far away.

src/vehicle.cpp

@@ -432,15 +432,20 @@ static std::array<Vehicle *, TOTAL_TILE_HASH_SIZE> _vehicle_tile_hash{};
 VehiclesNearTileXY::Iterator::Iterator(int32_t x, int32_t y)
 {
 	const int COLL_DIST = 6;
+	pos_rect.left = x - COLL_DIST;
+	pos_rect.right = x + COLL_DIST;
+	pos_rect.top = y - COLL_DIST;
+	pos_rect.bottom = y + COLL_DIST;
 
 	/* Hash area to scan */
-	this->hxmin = this->hx = GetTileHash1D((x - COLL_DIST) / TILE_SIZE);
+	this->hxmin = this->hx = GetTileHash1D(pos_rect.left / TILE_SIZE);
-	this->hxmax = GetTileHash1D((x + COLL_DIST) / TILE_SIZE);
+	this->hxmax = GetTileHash1D(pos_rect.right / TILE_SIZE);
-	this->hymin = this->hy = GetTileHash1D((y - COLL_DIST) / TILE_SIZE);
+	this->hymin = this->hy = GetTileHash1D(pos_rect.top / TILE_SIZE);
-	this->hymax = GetTileHash1D((y + COLL_DIST) / TILE_SIZE);
+	this->hymax = GetTileHash1D(pos_rect.bottom / TILE_SIZE);
 
 	this->current_veh = _vehicle_tile_hash[ComposeTileHash(this->hx, this->hy)];
 	this->SkipEmptyBuckets();
+	this->SkipFalseMatches();
 }
 
 /**
@@ -471,6 +476,14 @@ void VehiclesNearTileXY::Iterator::SkipEmptyBuckets()
 	}
 }
 
+/**
+ * Advance the internal state until it reaches a vehicle within the search area.
+ */
+void VehiclesNearTileXY::Iterator::SkipFalseMatches()
+{
+	while (this->current_veh != nullptr && !this->pos_rect.Contains({this->current_veh->x_pos, this->current_veh->y_pos})) this->Increment();
+}
+
 /**
  * Iterator constructor.
  * Find first vehicle on tile.

src/vehicle_func.h

@@ -139,6 +139,7 @@ public:
 		Iterator &operator++()
 		{
 			this->Increment();
+			this->SkipFalseMatches();
 			return *this;
 		}
 
@@ -149,12 +150,14 @@ public:
 			return result;
 		}
 	private:
+		Rect pos_rect;
 		uint hxmin, hxmax, hymin, hymax;
 		uint hx, hy;
 		Vehicle *current_veh;
 
 		void Increment();
 		void SkipEmptyBuckets();
+		void SkipFalseMatches();
 	};
 
 	explicit VehiclesNearTileXY(int32_t x, int32_t y) : start(x, y) {}