Reduce viewport invalidation area of track reservation changes

src/pbs.cpp

@@ -106,7 +106,7 @@ bool TryReserveRailTrack(TileIndex tile, Track t, bool trigger_stations)
 		if (IsBridgeTile(tile)) {
 			MarkBridgeDirty(tile, ZOOM_LVL_DRAW_MAP);
 		} else {
-			MarkTileDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
+			MarkTileGroundDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
 		}
 	}
 
@@ -155,7 +155,7 @@ bool TryReserveRailTrack(TileIndex tile, Track t, bool trigger_stations)
 			if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL) {
 				if (IsTunnel(tile) && !HasTunnelReservation(tile)) {
 					SetTunnelReservation(tile, true);
-					MarkTileDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
+					MarkTileGroundDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
 					return true;
 				}
 				if (IsBridge(tile)) {
@@ -200,7 +200,7 @@ void UnreserveRailTrack(TileIndex tile, Track t)
 		if (IsBridgeTile(tile)) {
 			MarkBridgeDirty(tile, ZOOM_LVL_DRAW_MAP);
 		} else {
-			MarkTileDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
+			MarkTileGroundDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
 		}
 	}
 

src/viewport.cpp

@@ -3358,6 +3358,15 @@ void MarkTileDirtyByTile(TileIndex tile, const ZoomLevel mark_dirty_if_zoomlevel
 	);
 }
 
+void MarkTileGroundDirtyByTile(TileIndex tile, const ZoomLevel mark_dirty_if_zoomlevel_is_below)
+{
+	int x = TileX(tile) * TILE_SIZE;
+	int y = TileY(tile) * TILE_SIZE;
+	Point top = RemapCoords(x, y, GetTileMaxPixelZ(tile));
+	Point bot = RemapCoords(x + TILE_SIZE, y + TILE_SIZE, GetTilePixelZ(tile));
+	MarkAllViewportsDirty(top.x - TILE_PIXELS * ZOOM_LVL_BASE, top.y - TILE_HEIGHT * ZOOM_LVL_BASE, top.x + TILE_PIXELS * ZOOM_LVL_BASE, bot.y);
+}
+
 void MarkTileLineDirty(const TileIndex from_tile, const TileIndex to_tile)
 {
 	assert(from_tile != INVALID_TILE);

src/viewport_func.h

@@ -104,6 +104,8 @@ static inline void MarkTileDirtyByTile(TileIndex tile, const ZoomLevel mark_dirt
 	MarkTileDirtyByTile(tile, mark_dirty_if_zoomlevel_is_below, bridge_level_offset, TileHeight(tile));
 }
 
+void MarkTileGroundDirtyByTile(TileIndex tile, const ZoomLevel mark_dirty_if_zoomlevel_is_below);
+
 ViewportMapType ChangeRenderMode(const ViewPort *vp, bool down);
 
 Point GetViewportStationMiddle(const ViewPort *vp, const Station *st);